Clickthrough-Composite Materials

Clickthrough -Composite Materials


Imagine you're surfing the Web. You arrive at a site. Scattered across the page are boxes. Such boxes beckon you with enticements of fantastic products, services or deals. In short, they're advertising something to you. Interested? Click on the box and you'll be transported to another page somewhere else on the Web. That page tries more aggressively to sell you something. Your mouseclick on that box is called a "click- through" in Internet parlance. How many clickthroughs an advertiser gets from a particular box is a very important measure of how successful that box of advertising is, whether he should continue buying the ad, how much he should pay for it, etc. For example, box that generates a lot of clickthroughs is a far deal for the advertiser. But how good the "deal" is depends on the cost of the ad and the quality of the clickthroughs, i.e. how many of the clickthroughs actually resulted in a product or service being bought and thus how much money you made. How well you keep track of the profitability of your Internet advertising (often called banner ads) may well determine how company well survives (or doesn't). See also Eyeballs. See Clickthrough Rate.

Clickthrough Rate

Imagine you've bought an advertisement on someone else's web site. You want visitors to that site to see your ad and be intrigued enough to click on your ad and be transported to your web site. When someone mouseclicks on your ad, it's called a "clickthrough." Now let's say that 10% of the people who visit that site click on your ad, that means you have a "clickthrough rate" of 10%. That is one (very minor) measure of the effectiveness of your ad. A better measure would be to figure how many people who clicked through actually bought your product and services and how much money you made on that sales. See Clickthrough.


Calling Line IDentification. Also called Caller ID. See Caller ID for a full explanation. See also ANI and CLASS.


  1. Clients are devices and software that request information. Clients are objects that use the resources of another object. A client is a fancy name for a PC on a local area network. It used to be called a workstation. Now it is the "client" of the server. See also Client Server, Client Server Model, Fat Client, Mainframe Server, Media Server and Thin Client.

  2. Customer.

Client Access Protocol

CAP. See iCalendar.

Client Application

Any computer program making use of the processing resources of another program.

Client Operating System

Operating System running on the client platform. See Client.

Client Pull

See Meta Tag.

Client Server

A computer on a local area network that you can request information or applications from. The idea is that you ” the user ” are the client and it ” the slave ” is the server. That was the original meaning of the term . Over time, client server began to refer to a computing system that splits the workload between desktop PCs (called "workstations") and one or more larger computers (called "servers") joined on a local area network (LAN). The splitting of tasks allows the use of desktop graphic user interfaces, like Microsoft's Windows or Apple Macintosh's operating system, which are easier to use (for most people) than the host/terminal world of mainframe computing, which placed a "dumb terminal" on a user's desk. That dumb terminal could only send and receive simple text-based material. And the less it sent, the faster it worked (lines were slow), so some of the "human interfaces" were very cryptic. You often were forced to spend weeks at school learning simple mainframe programs.

A good analogy of client-server computing, according to Peter Lewis of the New York Times is to think of client server as a restaurant where the waiter takes your order for a hamburger, goes to the kitchen and comes back with some raw meat and a bun. You get to cook the burger at your table and add your favorite condiments. In computerese, this is client/server, distributed computing, where some processing work is done by the customer at his or her table, instead of entirely in the kitchen (centralized computing in the old mainframe days). It sounds like more work, but it has many advantages. The service is faster. The food is cooked exactly to your liking, and the giant, expensive stove in the kitchen can be replaced by lots of cheap little grills. See Client Server Model, Downsizing, Reengineering and Server.

Client Server Computer Telephony

Client server computer telephony delivers ten benefits:

  1. Synchronized data screen and phone call pop. Your phone rings. The call comes with the calling number attached (via Caller ID or ANI). Your PBX or ACD passes that number (via Telephony Services) to your server, which does a quick database look up to see if it can find a name and database entry. Bingo, it finds an entry. It passes the call and the database entry simultaneously to whoever is going to answer the phone: The attendant. The boss. The sales agent. The customer service desk. The help desk. All this saves asking a lot of questions. Makes customers happier .

  2. Integrated messaging. Also called Unified Messaging. Voice, fax, electronic mail, image and video. All on the one screen. Here's the scenario. You arrive in the morning. Turn on your PC. Your PC logs onto your LAN and its various servers. In seconds, it gives you a screen listing all your messages ” voice mail, electronic mail, fax mail, reports , compound documents .... Anything and everything that came in for you. Each is one line.

    Each line tells you whom it's from. What it is. How big it is. How urgent. Skip down. Click. Your PC loads up the application. Your LAN hunts down the message. Bingo, it's on screen. If it contains voice ” maybe it's a voice mail or compound document with voice in it ” it rings your phone (or your headset) and plays the voice to you. Or, if you have a sound card in your PC, it can play the voice through your own PC. If it's an image, it will hunt down (also called launch) imaging software which can open the image you have received, letting you see it. Ditto, if it's a video message.

    Messages are deluging us. To stop them is to stop progress. But to run your eye down the list, one line per entry. Pick the key ones. Junk the junk ones. Postpone the others. That's what integrated messaging is all about. Putting some order back into your life.

  3. Database transactions. Customer look ups. There are bank account balances , ticket buys, airline reservations , catalog requests , movie times, etc. Doing business over the phone is exploding. Today, the caller inputs his request by touchtone or by recognized speech. The system responds with speech and/or fax. Today's systems are limited in size and flexibility. The voice processing application and the database typically share the same processor, often a PC. Split them. Spread the processing and database access burden . Join them on a LAN (for the data) and on new, broader voice processing "LANs," like SCSA or MVIP. You've suddenly got a computer telephony system that knows no growth constraints. You could also get the system to front-end an operator or an agent. Once the caller has punched in all his information, then the call and the screen can be simultaneously passed to the agent.

  4. Telephony work groups. Sales groups. Collections groups. Help desks. R&D. We work in groups. But traditional telephony doesn't. Telephony today is BIG. Telephony today is one giant phone system for the building, for the campus. Everyone shares the same automated attendant, the same voice mail, the same ubiquitous, universal, generic telephone features. But they shouldn't. The sellers need phones that grab the caller's phone number, do a look-up on what the customer bought last and quickly route the call to the appropriate (or available) salesperson. The one who sold the customer last time. The company's help desk needs a front end voice response system that asks for the customer's serial number, some indication of the problem and tries to solve the problem by instantly sending a fax or encouraging the caller to punch his way to one of many canned solutions. "The 10 biggest problems our customers have." When all else fails, the caller can be transferred to a live human, expert at diagnosing and solving his pressing problem. A development group might need e- mails and faxes of meeting agendas sent, meeting reminder notices phoned and scheduled video conferences set up. All automatically. The accounts receivable department needs a predictive dialer to dial all our deadbeats. The telemarketing department also needs a predictive dialer, but different programming.

  5. Desktop telephony. There are two important aspects. Call control and media processing services. Call control (also called call processing) is a fancy name for using your PC to get to all your phone system's features ” especially those you have difficulty getting to with the forgettable commands phone makers foist on us. *39 to transfer? Or it is *79. With attractive PC screens, you point and click to easy conferencing, transferring, listening to voice mail messages, forwarding, etc. There are enormous personal productivity benefits to running your office phone from your PC: You can dial by name, not by a number you can't remember. You can set up conference calls by clicking on names and have your PC call the participants and call you only when they're all on the phone. You can transfer easily. You can work your voice mail more easily on screen, instead of having to remember "Dial 3 for rewind," "Dial 2 to save," and other obscure commands. Here's a wonderful quote from Marshall R. Goldberg, Developer Relations Group at Microsoft. He says "Voice mail systems that could benefit through integration with the personal computer largely remain isolated, difficult to use, and inflexible . Browsing, storing messages in hierarchical folders, and integration of address books ” functions just about everyone could use ” are either unavailable or unusable."

    The second benefit is media control. Media control is a fancy name for affecting the content of the call. You may wish to record the phone call you're on. You may wish to have all or part of your phone call clipped and sent to someone else ” as you often do today with voice mail messages. You may wish to simply file your conversations away in appropriate folders. You may wish to be able to call your PC and get it to read you back any e-mails or faxes you received in the last day or so.

  6. Applying intelligence. A PC is programmable. The typical office phone isn't. A PC can be programmed to act as your personal secretary, handling different calls differently. It can be programmed to include commands, such as "If Joe calls, break into my conversation and tell me." "If Robert calls, send him to voice mail." etc.

  7. The Compound Document. The typed document lacks life. But add voice, image and video clips to it and it gets life. The LAN makes the compound document easier to achieve. The Compound Document gets attention.

  8. Management of phone networks. Today, phone networks are very difficult to manage. Often the PBX is managed separately from the voice mail, which is managed separately from the call accounting, etc. It's a rare day in any corporate life when the whole system is up to date, with extensions, bills and voice mail mailboxes reflecting the reality of what's actually happening. The latest generations of LAN software ” NetWare 4.1 and Windows NT ” have solid enterprise-wide directories and far easier management tools. Integrate these LAN management tools with telecommunications management, and potentially all you need is to make one entry (for a new employee, a change, etc.) and the whole system ” telecom and computing ” could update itself automatically and even issue change orders to the MIS and telecom departments and vendors .

  9. No dedicated hardware in the PC. With only one link ” from the switch to the LAN ” there's no need to open the desktop PC and place specialized telephony hardware in each PC that wants to take advantage of the new LAN-based telephony features.

  10. Switch elimination . The ultimate potential advantage of LAN-based telephony is to eliminate the connection to the switch (PBX or ACD) by simply populating the LAN server (now called a telephony server) with specialized computer telephony cards and running the company's or department's phones off the telephony server directly.

Client Server Model

In most cases, the "client" is a desktop computing device or program "served" by another networked computing device. Computers are integrated over the network by an application, which provides a single system image. The server can be a minicomputer, workstation, or microcomputer with attached storage devices. A client can be served by multiple servers. See Client Server.

Client Software

An Internet access term. Multiprotocol PPP client software allowing dial-in access to the public Internet or corporate LANs via a dialup switch or a remote access server. The client software dialer is responsible for establishing/terminating the dial- in connection. The client software PPP driver manages the traffic sent/received across the network link.

Client Tennis

Harris Lydon is a great tennis player, but he's also my stockbroker. When he plays me in tennis, he lets me win occcasional points. That's called playing client tennis. If he weren't playing client tennis, I'd never win a point. He's that good. I'm not that bad.


Clifton Powell is the best educator at Bellcore, now Telcordia Technologies. I know because he told me so. He also said he would recommend my dictionary even more strongly to his people than he does. Powell to the people. Right on!


What personnel wear to climb wooden poles. Officially called linesman's climbers, but are often known as spurs, hooks, and gaffs. They consist of a steel shanks that strap to a person's leg. The inside has a spike used to stab the pole.

Climbing Belt

A belt that communications/power/construction personnel use to attach themselves to poles or tower structures. Also called safety belt and body belt.


  1. Calling Line Identification Presentation. Also known as CNIP (Calling Number Identification Presentation). A supplementary service provided by certain wireless "cellular" services, such as GSM (Global System for Mobile Communications) and PCS (Personal Communications Services). Assuming that your subscriber profile includes this service, the number of the calling party displays on your wireless telephone. If the calling party uses CNIR (Calling Number Identification Restriction) however, your display says "PRIVATE." You can choose to have PRIVATE CALLS automatically transferred to your voice mailbox, while retaining the option to override that instruction with a simple keypad command. This feature is known variously as Caller ID and Calling Line ID (CLID) in the wired world. Whether in the wireless or the wired world, this feature is made available courtesy of SS7. See also GSM, PCS, and SS7.

  2. As in Video Clip. A small piece of video. Originally a video clip was a piece of celluloid physically cut out of a larger movie. Now it could be digital. And it just means it's a small video.

Clip On Toll Fraud

Clip on toll fraud occurs when someone connects a phone between someone else's phone (typically a coin phone) and the central office and makes unlawful toll calls. The term "clip on" comes because the telephone service thief "clips on" to the line. Clip on toll fraud is often done on COCOT (Customer Owned Coin Operated Telephone) phone lines because these lines do not enjoy the same protection from toll fraud which is afforded to coin phone lines which local telcos provide to their own coin phones.


A generic term for a place in software which holds text, pictures or images that you are copying or moving between applications. The clipboard is a temporary holding place only. When you cut or copy a new item it will replace the current clipboard contents. In other words, there's usually only one clipboard. Windows uses a clipboard and so does the Apple Macintosh.


A Windows NT term. Windows NT is soon to be known as Windows 2000. Permanent storage of information you want to save and share with others. This differs from the Clipboard which temporarily stores information. You can save the current contents of the clipboard, which temporarily stores information. You can then share that information, allowing others to connect to the Clipboard. See Clipbook Page.

Clipbook Page

A Windows NT term. Windows NT is soon to be known as Windows 2000. A unit of information pasted into a local ClipBook. The ClipBook page is permanently saved. Information on a ClipBook page can be copied back onto the Clipboard and then pasted into documents. You can share ClipBook pages on the notework.

Clipbook Service

A Windows NT term. Supports the Clipbook Viewer application, allowing pages to be seen by remote ClipBooks.

Clipped Frame

Transmit packet lost at the interface because no buffer space was available to the host transmit driver for outgoing data.


A circuit or device that limits the instantaneous output signal amplitude to a predetermined maximum value, regardless of the amplitude of the input signal. See Clipper Chip.

Clipper Chip

A microprocessor chip, officially known as the MYK-78, which the Federal Government wants to add to phones and data communications equipment. The chip would ensure that conversations in Clipper-equipped communicating equipment would be private ” from everybody except the Government. With a court -approved wiretap, an agency like the FBI, could listen in, since the Government would have the key to Clipper. On February 4, 1994, the Clinton White House announced its approval of the Clipper chip and the "Crypto War" broke out ” with many companies and individuals urging a stop to Clipper. In late Spring, 1994 an AT&T Bell Labs researcher revealed that he had found a serious flaw in the Clipper technology. As of writing it wasn't clear what would happen to the Clipper Chip. See NSA.


Clipping has two basic meanings. The first refers to the effect caused by a simplex (one way at a time) speakerphone. Here the conversation goes one way. When the other person wants to talk, the voice path has to reverse (to "flip"). While the flipping takes place, a few sounds are "clipped" from that person's conversation. This phenomenon happens on some long distance and many overseas channels. These channels are so expensive, they are simultaneously shared by many conversations. Gaps in your conversation are filled by other people's conversation. But when you start talking, the equipment has to recognize you're now talking, find some capacity for your conversation, and send it. In the process of doing this, your first word or part of your first word might be "clipped" and the conversation will sound "broken."

The second way your voice is clipped is what happens every day on the telephone. You're squeezing your own voice which typically spans 10,000 Hertz into a voice channel which is only 3,000 Hertz. This clips the extremes of your conversation ” the higher sounds. As a result, your voice sounds flatter over the phone. As you become more economical and try to squeeze your voice into smaller capacity channels, so it becomes increasingly clipped.


Calling Line Identification Restriction, A wireless telecommunications term. A supplementary service provided under GSM (Global System for Mobile Communications). See GSM.


Code Common Language Location Identifier. Pronounced silly code. An alphanumeric code of 11 characters , CLLI was developed by Bellcore (now Telcordia Technologies) as a method of identifying physical locations and equipment such as buildings , central offices, poles, and antennas. Here is information from Telcordia: How Are CLLI Codes Developed? Each CLLI code conforms to one of three basic formats (Network Entity, Network Support Site and Customer Site). Each format, in turn, determines how these six coding elements are used:

  • Geographical Codes (Example: DNVR = Denver) Typically assigned to cities, towns, suburbs, villages, hamlets, military installations and international airports, geographical codes can also be mapped to mountains , bodies of water and satellites in fixed-earth orbit .

  • Geopolitical Codes (Example: CO = Colorado) Typically assigned to countries , states and provinces , geopolitical and geographical codes can be combined to form a location identifier that is unique worldwide.

  • Network-Site Codes (Example: 56 = A central office on Main Street) This element is used with geographical and geopolitical codes to represent buildings, structures, enclosures or other locations at which there is a need to identify and describe one or more functional entities. This category includes central office buildings, business and commercial offices, certain microwave-radio relay buildings and earth stations , universities, hospitals , military bases and other government complexes, garages, sheds and small buildings, phone centers and controlled environmental vaults.

  • Network-Entity Codes (Example: DS0 = A digital switch) This element can be used with geographical, geopolitical and network-site codes to identify and describe functional categories of equipment, administrative groups or maintenance centers involved in the operations taking place at a given location.

  • Network Support-Site Codes (Example: P1234 = A telephone pole) This element can be used with geographical and geopolitical codes to identify and describe the location of international boundaries or crossing points, end points, fiber nodes, cable and facility junctions, manholes, poles, radio-equipment sites, repeaters and toll stations.

  • Customer Site Codes (Example: 1A101 = A customer) This element can be used with geographical and geopolitical codes to identify and describe customer locations associated with switched-service networks, centrex installations; trunk forecasting, cable, carrier or fiber terminations, NCTE, CPE and PBX equipment, military installations, shopping malls, universities and hospitals. Consider the real-life example of NYCMNY18DSO. The first four characters identify the place name (NYCM is New York City Manhattan). The following two characters identify the state, region or territory (NY is New York). The remaining five characters identify the specific item at that place (18DSO is the AT&T 5E Digital Serving Office on West 18th Street, between Seventh and Eight Avenues). Phone companies use CLLI Codes for a variety of purposes, including identifying and ordering private lines and trapping and tracing of annoying or threatening calls. See Annoyance Call Bureau, CFA, CLLI Code ” Facility Identification, Trap and Trace, and Wire Tap.

CLLI Code - Facility Identification

CLFI codes provide unique identification of facilities (cables and carrier systems) between any two interconnected CLLI coded locations. The CLFI code is a variable length, mnemonic code with a maximum of 38 characters. Example: 101T1LSANCA03NWRKNJAA. This example says that there is T-1 carrier connected between the Los Angeles, California Central Office to the Newark, New Jersey Central Office. See CLLI Code.


Career Limiting Move. An ill-advised activity. Trashing your boss while he or she is within earshot is a serious CLM. Sending emails through the company's server which can be read by management long after you think you've deleted them is another CLM.


Connectionless Network Protocol. An OSI network layer protocol that does not require a circuit to be established before data is transmitted. The OSI protocol for providing the OSI Connectionless Network Service (data gram service). CLNP is the OSI equivalent to Internet IP, and is sometimes called ISO IP.


Connectionsless Network Service. A Network Layer methodology which does not require a receiver's immediate acknowledgment of communications. See Connectionless Network Service.


Central Limit Order Book. According to the New York Times, if stock market regulators in the United States have their way, stock prices will eventually be listed in one place, though they might still be traded on multiple exchanges.


  1. A clock is an oscillator-generated signal that provides a timing reference for a transmission link. A clock provides signals used in a transmission system to control the timing of certain functions such as the duration of signal elements or the sampling rate. It also generates periodic, accurately spaced signals used for such purposes as timing, regulation of the operations of a processor, or generation of interrupts. In short, a clock has two functions:

    1. To generate periodic signals for synchronization on a transmission facility.

    2. To provide a time base for the sampling of signal elements. Used in computers, a clock synchronizes certain procedures, such as communication with other devices. It simply keeps track of time, which allows computers to do the same things at the same time so they don't "bump" into each other.

  2. A clock is an internal timing device in the form of a computer chip that uses a quartz crystal to generate a uniform electrical frequency from which digital pulses are created. A clock keeps track of hours, minutes, and seconds and makes this data available to computer programs.

  3. A clock is a timer set to interrupt a CPU (Centralized Processing Unit) at regular intervals in order to provide equal time to all the users of the computer. A clock also maintains the uniform transmission of data between the sending and receiving terminals and computers. In short a clock has many functions. See Network Slip, Timing, and Stratum Level.

Clock Bias

The difference between the GPS clock's indicated time and true universal time. GPS is Global Positioning System. See GPS.

Clock Cycle

The time that elapses from one read or write operation to another in the main memory of a computer's central processing unit (CPU). The more tasks that can be accomplished per cycle, the more efficient the chip. Some chips like the i860 chip can execute two instructions and three operations per clock cycle.

Clock Difference

A measure of the separation between the respective time marks of two clocks. Clock differences must be reported as algebraic quantities measured on the same time scale. The date of the measurement should be given.

Clock Doubling

Refers a computer whose internal CPU clock runs twice as fast as the clock for the rest of computer. This has the effect of increasing the computer's speed without the expense of high-speed hardware.

Clock Slack

See PPM.

Clock Speed

The speed at which the microprocessor in your PC synchronizes and regulates its workflow, measure in megahertz . The higher the clock speed, the faster the processor can process data. Other factors such as RAM, hard disk speed, hardware and bus widths have an effect on its performance. It is also known as clock rate. Each CPU (Centralized Processing Unit) of a computer contains a special clock circuitry which is connected to a quartz crystal that is much like the one in your watch. The quartz crystal's vibrations, which are very fast, coordinate the CPU's operation, keeping everything in step, and regulating the rate at which instructions are executed. CPU clock speeds are measured in megahertz, or MHz (million cycles per second), with each cycle known as a "clock tick." While the clock speeds of contemporary PC CPUs range from a slow of 4.77 MHz (the original IBM PC) to 3 GHz and more coming, the main system clock ticks at a rate of 66 MHz for all PCs. Some PCs are "superscalar," executing multiple instructions per clock cycle. So, clock speed is a misleading term. It is only one way of measuring the speed of a computer. One other critical way is how fast you can read and write information to the hard disk. How important that is depends on whether you're running a program with lots of access to your hard drive (e.g., a database program) or running a program which uses a lot of calculations in RAM (e.g., a spreadsheet).

Clock Tolerance

The maximum permissible departure of a clock indication from a designated time reference such as Coordinated Universal Time.


In synchronous communication, a periodic signal used to synchronize transmission and reception of data and control characters.

Clockwise Polarized Wave

An elliptically or circularly polarized electromagnetic wave in which the direction of rotation of the electric vector is clockwise as seen by an observer looking in the direction of propagation of the wave.


A clone, as a noun, is a person or thing that duplicates, imitates, or closely resembles another in appearance, function, performance or style. A clone, as a verb, means to produce an exact copy of. There are many different " clones " in the telecommunications and PC business. A cloned PC is the same as another one. You might need to make clone PCs if you want to give "standard issue" PCs to your people. To clone a PC, you create all the software you want and the configuration you want on one PC. You connect that PC to a network. Then you use a program ” a popular one is called "Ghost" ” which copies the PC's entire hard disk to a server on your network. You then make a normal boot floppy disk, add "Ghost" to the floppy disk and go to another new machine, which you've attached to the network. You insert the boot disk into the floppy drive and turn on the machine. It reads the boot disk, loads MS-DOS and Ghost, goes to the server and retrieves (i.e. copies over) all the software it needs to make itself an identical clone of the original PC.

A clone can be a mobile device, say a cellular telephone, that claims to possess the same address identifier as another mobile device. See Clone Fraud.

Clone Fraud

A way of using cellular phones to steal phone calls. In clone fraud, a legitimate serial number is programmed into an imposter's cellular telephone. This allows unauthorized calling to go on until a huge bill appears on the mailbox of the bewildered subscriber to whom the serial number actually belongs. Crooks get the numbers because the numbers are broadcast with every cellular call and can be picked up by ordinary radio scanners, which you can often buy at your local electronics store. According to the Wall Street Journal, cellular thieves take advantage of the fact that when a cellular phone call is placed, the phone's unique electronic code is transmitted over the airwaves to update the cellular network on the user's location. Service thieves wait near the busy areas - highways, financial districts - and use scanners to lift the codes from legitimate users. Thousands of such hijacked numbers can be later downloaded through a computer into "clone" phones. Thus, a clone phone lets a user place potentially hundreds of call that are billed to the legitimate owner of the original number. See Cloned Phone and Tumbling.

Cloned Phone

A cellular phone has two basic ways it identifies itself to the cellular phone company it wants to use ” its own telephone number (which can be changed) and a special secret number that's embedded into silicon inside the phone. That number is called an Electronic Serial Number, or ESN. When the phone wants to make a call, it sends those numbers and the cellular carrier uses them to check if the call is authorized. But because the information is traveling through the air, anyone with a scanner can pick up the information and retransmit it later, thus creating a "cloned phone" and pretending that he's authorized to make the call. Of course, the owner of the cloned phone ultimately gets the bill and a nasty shock .


Central Location On-Line Entry System. CLONES is the repository for CLLI codes.

Cloning Fraud

Cloning Fraud Occurs when criminals use scanners to obtain legitimate MIN/ESN/PIN combinations and then program them into illegitimate phones. Such number combinations with PINs are even more valuable to cloners. These cloners can rack up millions of dollars in losses for carriers by creating phone banks, where either illegitimate minutes are resold or cloned phones are sold.

Close Coupling

The condition in which two coils are placed in close magnetic relation to each other, thus establishing a high degree of mutual induction.

Close Talk

A voice recognition term. An arrangement where a microphone is fewer than four inches from the speaker's mouth.

Closed Architecture

Proprietary design that is compatible only with hardware and software from a single vendor of a single product family. Contrast with Open Architecture.

Closed Captioning

A service, designed for people with hearing disabilities , that provides a simultaneous visual presentation of the sound associated with a television program. Closed captioning is not visible except on a TV receiver designed to display it or by use of a specially installed decoder.

Closed End

The end of a Foreign Exchange ” FX ” line which ends on a PBX, a key system or a telephone. The closed end is the end of the circuit beyond which a call cannot progress further. The other end of the FX circuit is called the "open end," because calls can progress further.

Closed Loop System

  1. A closed electrical circuit into which a standard signal is fed and received instantly. A measure of the difference between the input signal and the output signal is a measure of the error, and potentially what's causing it.

  2. RFID tracking systems set up within a company. Since the tracked item never leaves the company's control, it does not need to worry about using technology based on open standards.

Closed User Group

A group of specified users of a data network that is assigned a facility that permits them to communicate with each other but precludes communications with other users of the service or services.


Telecommunications closet. An enclosed space for housing telecommunications equipment, cable terminations, and cross-connect cabling that is the recognized location of the cross-connect between the backbone and horizontal facilities.


A cabinet, pedestal, or case used to enclose cable sheath openings necessary for splicing or terminating fibers.


  1. Beginning with AT&T's BDN (Bell Data Network) and ACS (Advanced Communication System) offerings, the data network was depicted as a "cloud." The user data was presented at one side of the carrier cloud, and was delivered at the other side. What went on inside the cloud was obscured from view. The thinking behind this heavily conceptual sell was that the user needn't be concerned with what went on inside the carrier network; rather, that was the concern and responsibility of the carrier. While BDN, later known as ACS and later still as Net 1000 was unsuccessful , the concept of the cloud was a huge success.

    The cloud is particularly appropriate for illustration of the Internet, as it is a network of networks of uncertain definition. In fact, the use of packet switching and the TCP/IP protocol suite are about the only things about the Internet that are certain. The nature of the physical circuits; the placement of switches and routers; the use of various tunneling protocols, if any; the use of various protocols for grade of service support, if any; and many other specifics vary widely from network to network in this network of networks. The specifics are sensitive to the physical locations of the originating and terminating devices, the applications supported, the ISPs and backbone carriers involved, the path taken by the data, and other variables .

    Some of the newer high-speed data, phone company- offered services resemble a local area network. You connect to them directly. To make a call, you don't actually dial a number as you do on a circuit-switched service, you just transmit, putting an address at the front of your transmission. The service reads the address and sends it where you want. Like a LAN, everything is connected and on line. The concept is to get stuff sent from one place to another much faster than would be possible if you had to wait to dial, for the circuit to be set up, for the machine at the other end to answer, etc. In these high-speed services, the circuit is "always set up." The provider (the phone company) refers to its network as a "cloud." And when you see diagrams of these newer high-speed services, like ATM and frame relay, you see the carrier portion drawn as a cloud (like the one you see in the sky).

  2. The cloud could also be the Internet. Microsoft's .net initiative revolves around creating software programs that do not reside on any one computer but instead exist in the "cloud" of computers that make up the Internet. The move from the desktop-based computing paradigm that Microsoft has controlled to an open-network approach would be a crucial one for all computer users and software programmers. Beginning in the summer of 2000, Bill Gates of Microsoft has been working to transform his company through systems like the recently announced Hailstorm project, which aims to move most of a computer user's personal information ” from daily calendar to banking information ” from the desktop or laptop PC and into the network cloud, where a user could have access to it from a variety of devices and locations. To hasten this grand migration, according to the New York Times, Microsoft has been courting software developers, hoping to persuade them to write for its new operating-system-in-the-sky.

  3. The cloud is also marketing speak. A true story: A vendor of 802.11b wireless networking told the management of the Ritz Carlton in Jamaica that it would install a "wireless cloud" over the entire hotel such that no matter where you were in the hotel, you could be on the wireless network and access the Internet and your email, etc. The hotel believed this. When I visited, wireless service was fine in the lobby and the convention center and pretty well zero everywhere else (including your room).

    See Cloud Nine.

Cloud Nine

When someone is feeling great they're "on cloud nine." The reason for this is that clouds are numbered according to the altitudes they attain, with nine being the highest cloud. If someone is said to be on cloud nine, that person is floating well above their worldly cares.


Cell Loss Priority: This bit in the ATM cell header indicates two levels of priority for ATM cells. CLP=0 cells are higher priority than CLP=1 cells. CLP=1 cells may be discarded during periods of congestion to preserve the CLR of CLP=0 cells . See also Cell -loss Priority Field.


  1. Cell Loss Ratio: CLR is a negotiated QoS (Quality of Service) parameter and acceptable values are network specific. The objective is to minimize CLR provided the end-system adapts the traffic to the changing ATM layer transfer characteristics. The Cell Loss Ratio is defined for a connection as: Lost Cells/Total Transmitted Cells. The CLR parameter is the value of CLR that the network agrees to offer as an objective over the lifetime of the connection. It is expressed as an order of magnitude, having a range of 10-1 to 10-15 and unspecified.

  2. Circuit Layout Record. Is an identifier of what type of service each telecommunications circuit has.


Control Line Setting.


Competitive Local Service Provider. Interchangeable term with ALT and CLEC.


Additional Listing.


Connectionless Transport Protocol. Provides for end-to-end Transport data addressing (via Transport selector) and error control (via checksum), but cannot guarantee delivery or provide flow control. The OSI equivalent of UDP.


ConnectionLess Transport Service.


I don't care to belong to a club that accepts people like me as members ” Groucho Marx.


  1. Collection of terminals or other devices in a single location. A cluster control unit and a cluster controller in IBM 3270 systems are devices that control the input/output operations of a group (cluster) of display stations. See also Clustering.

  2. Unit of storage allocation used by MS-DOS usually consisting of four or more 512- byte sectors.

  3. Physical grouping of workstations that share one or more panel runs.

  4. A mini-network of PCs that work in a fault-resilient manner.

  5. A cluster is a group of computers and storage devices that function as a single system.

Cluster Analysis

A statistical technique for looking at "complex" relationships between data. It takes into account relationships that are non-linear. This is the main technique used for developing a segmentation model to group individuals together who have similar characteristics. i.e. people of a similar type "cluster" together ("birds of a feather flock together"). The technique analyses the spatial distances between the data to determine the characteristics of the clusters. For example, one cluster may be made up of predominately young males over 45 years old who have several saving and investment plan insurance and tend to live in inner cities. Another cluster may be made up of similar demographic data but these people have several credit cards, loans and credit agreements.

Cluster Controller

A device that can control input/output operations of more than one device connected to it (e.g. a terminal). An interface between several bisynchronous devices and a PAD, NC or communication facility. The cluster controller handles remote communications processing for its attached devices. Most common types are IBM 327X.

Cluster Size

An operating function or term describing the number of sectors that the operating system allocates each time disk space is needed.


A client/server term describing the collection of servers or data in a central location for reasons of increased effectiveness and efficiency of security, administration and performance. Clustering is to help servers become fault resilient. Clustering helps to overcome problems associated with the client/server paradigm in general. In the old days of "heavy iron" (mainframes), user access to applications and files was carefully controlled. The target applications and files were resident on a highly redundant, carefully administered and tightly secured mainframe computer. As client/server has taken hold, the processors tend to be distributed in order that they are located in closer proximity to users, thereby relieving the strain on network resources, improving response times, and so on. The downside is that the resources are more difficult to manage, secure and control. Clustering the servers in a centralized location places them back in the hands of centralized MIS management, relieving these problems. There are two forms of clustering. The first form involves segmenting and spreading the database across multiple servers, with each segment of the database residing on multiple servers in order to achieve some level of redundancy. The second form positions the servers in a communications role, with each providing access for a group of users to data housed in a central repository, generally in the form of a minicomputer or mainframe.


An imaging term. Color Look-Up Table. The palette used in an indexed color system. Usually consists of 256 colors.


Wave reflections from obstructions such as terrain and buildings, which may show up as echoes or unidentifiable blips on a radar screen, thus interfering with scanning.


  1. Computing Module.

  2. Configuration Management. A wireless telecommunications term. The tracking, coordination, and administration of software and hardware related to telecommunication or information systems. Versions are controlled and tracked.

  3. Cable Modem.

  4. Commercial Grade. A grade of cable specified in the National Electrical Code (NEC), CM cable can be run through a wall without being housed in a conduit. See also CMP and CMR.


Communications Managers Association. An independent, not-for-profit users group formed in 1948 and serving the New York/New Jersey area. CMA provides a forum for peer-to-peer discussion of common issues, evaluation of technologies and their business applications, and the fostering of constructive relationships between suppliers and users. In addition to end users, CMA welcomes non-voting "Partners" in the form of vendors, consultants and associations.


  1. Common Messaging Calls. A messaging standard defined by the X.400 API Association. CMC 1.0 defines a basic set of calls to inject and extract messages and files and access address information. CMC is intended to define a useful common denominator across a wide variety of messaging systems. The idea is that an electronic mail system, no matter how crude, should be able to support a CMC front end. CMC's major "competition" is MAPI ” Messaging Application Programming Interface ” from Microsoft, though simple MAPI is almost identical to CMC.

  2. Cellular Mobile Carrier.


Charge Modulated Device, an active pixel sensor for imaging derived from CCD pixel technology and CMOS transistor technology. CMD are analog sensors, the digitizing happens when the electrons are passed through the analog to digital converter. The A to D converter converts the analog signal to a digital file or signal. Like the CCD, the CMD is used as an image capture device, CMDs are noisier imaging devices.


Centralized Message Distribution System. An RBOC-owned clearinghouse for CATS billing data. The RBOCs use it to exchange billing data with each other and to determine the financial settlements between them. They also clear ITC data through CMDS and charge the ITCs for doing this.


Cellular Message Encryption Algorithm. See ECMEA.


Cable Modem to CPE Interface. An element of DOCSIS (Data Over Cable Service Interface Specification), a project intended to develop a set of specifications for high-speed data transfer over cable television systems. CMCI is the interface between the cable modem and the CPE (Customer Premise Equipment), which typically would be in the form of a PC. See also DOCSIS.


Control Mode Idle: C Idle Byte CO.


Common Management Information Protocol. CMIP is the network management standard for OSI networks. It has some features that are lacking in SNMP and SNMP-2, and is more complex. CMIP has a far smaller mind share and market share than SNMP in North America, though support for this standard is sometimes mandated , especially in Europe. CMIP is an ITU-TSS standard for the message formats and procedures used to exchange management information in order to operate , administer, maintain and provision a network. In short, CMIP is the protocol used for exchanging network management information. Typically, this information is exchanged between two management stations. CMIP can, however, be used to exchange information between an application and a management station. CMIP has been designed for OSI networks, but it is transport independent. Theoretically, it could run across a variety of transports, including, for example, IBM's Systems Network Architecture. See CMIP/CMIS, MIB and SNMP.


Common Management Information Protocol/Common Management Information Services. An OSI network management protocol/service interface created and standardized by ISO for managing heterogeneous networks.


Common Management Information Service Element. A wireless telecommunications term. The functionality provided by CMIP in transporting network management information.


Connection-Mode Network Service. Extends local X.25 switching to a variety of media (Ethernet, FDDI, Token Ring).


Short for "CMIP Over Logical Link Control". An implementation of the CMIP protocol over the second layer of the OSI protocol stack, to be proposed as a standard by 3 Com Corp. and IBM. The goal of CMOL is to create agents that require significantly less memory than CMIP implemented over OSI, or SNMP implemented over UDP.


Complementary Metal Oxide Semiconductor, a technology used in transistors that are manufactured into most of today's computer microchips. In CMOS technology, negative charge (N-type transistors) and positive charge carriers (P-type transistors) are used in a complementary way to form a current gate that creates an effective means of electrical control. CMOS transistors draw almost no power when not in use. See CMOS RAM and CMOS Setup.


Complementary Metal Oxide Semiconductor Random Access Memory. Memory which contains a personal computer's configuration information. CMOS RAM must have continuous power to preserve its memory. This power is typically supplied by a lithium battery.

CMOS Setup

A program which prepares the system to work. CMOS setup records your PC's hardware configuration information into CMOS RAM. It must be modified when you add, change or remove hardware.


CMIP Over TCP/IP. More correctly, Common Management Information Protocol over TCP/IP. The original CMOT was described by RFC 1095, which is now obsolete. The new RFC 1189 "defines the means for implementing the IS version of CMIS/CMIP on top of both IP-based and OSI-based Internet transport protocols...", an expanded charter. The portion that is CMIS/CMIP over TCP/IP is still referred to as "CMOT". Someone referred to the new RFC as "CMIP over RFC 1066". In short, CMOT is an Internet standard defining the use of CMIP for managing the TCP/IP-based Internet and other attached networks. While the OSI-based CMIP is viewed as the most elegant long-term network management solution for such networks, it has not received the widespread acceptance of SNMP (Simple Network Management Protocol), which is much simpler (hence the name) and much more easily implemented. See also CMIP, OSI Reference Model and SNMP.


Communications Plenum Cable. A grade of cable specified in the National Electrical Code, CMP cable is the plenum version of CM (Commercial Grade). Not only can CMP cable be run through walls without being placed in a conduit, but it also can be run in fire-critical areas such as drop ceilings or raised floors, where air circulates, often as the air return for air conditioning. CMP is insulated and sheathed in a low-smoke, fire-retardant material. It also costs a lot more than normal telephone or data wiring. See also CM, CMP-50 and CMR.


See NFPNA 90A.


  1. An ATM term. Cell Misinsertion Rate: The ratio of cells received at an endpoint that were not originally transmitted by the source end in relation to the total number of cells properly transmitted.

  2. CoMercial Riser grade. A grade of cable specified in the National Electrical Code (NEC), CMR cable can be run vertically between floors of a building without being housed in a conduit. See also CM and CMP.


Cable Modem to Radio Frequency Interface. An element of DOCSIS (Data Over Cable Service Interface Specification), a project intended to develop a set of specifications for high-speed data transfer over cable television systems. At the CPE (Customer Premise Equipment) end of the network, the CMRFI provides the interface between the cable modem and the cable system coax drop. The CMRFI specification will include all physical, link and network level aspects of the communications interface, including RF levels, modulation techniques, coding schemes, and multiplexing. See also DOCSIS.


Commercial Mobile Radio Service. One type of wireless carrier, as defined by the Federal Communications Commission. Public use licenses are issued to carriers intending to serve multiple parties as their own subscribers or customers. Licenses are exclusive and are specific to geographic areas and a specified period of time. CMRS providers can include Personal Communications Services (PCS) providers; Air-to-Ground Carriers; Radio Common Carriers, including Paging and Radio Mobile Service providers; Cellular Carriers; Enhanced Specialized Mobile Radio Carriers (ESMRs); and Personal Mobile Radio Carriers (PMR).


  1. Call Management Services. Canadian term for local calling features based on CLID (Calling Line Identification).

  2. Content Management System. A fancy name for web authoring software. See Content Management System.

CMS 8800

Cellular Mobile Telephone Service (North American version).


Cable Modem Telco Return Interface. An element of DOCSIS (Data Over Cable Service Interface Specification), a project intended to develop a set of specifications for high-speed data transfer over cable television systems. At the head-end of the network, the CMTRI provides the interface between the cable modem system and PSTN. See also DOCSIS.


  1. CMTS stands for the Cellular Mobile Telephone System. The original and still, most common CMTS is a low- powered , duplex, radio/telephone which operates between 800 and 900 MHz, using multiple transceiver sites linked to a central computer for coordination. The sites, or "cells," named for their honeycomb shape, cover a range of one to six, or more, miles in each direction. The cells overlap one another and operate at different transmitting and receiving frequencies in order to eliminate crosstalk when transmitting from cell to cell. Each cell can accommodate up to 45 different voice channel transceivers. When a cellular phone is activated, it searches available channels for the strongest signal and locks onto it. While in motion, if the signal strength begins to fade, the telephone will automatically switch signal frequencies or cells as necessary without operator assistance. If it fails to find an acceptable signal, it will display an "out of service" or "no service" message, indicating that it has reached the limit of its range and is unable to communicate. Each cellular telephone has a unique identification number which allows the Mobile Telephone Switching Office (MTSO) to track and coordinate all mobile phones in its service area. This ID number is known as the Electronic Security Number (ESN). The ESN and cellular phone's telephone number are NOT the same. The ESN is a permanent number engraved into a memory chip called a PROM or EPROM, located in the telephone chassis. This number cannot be changed through programming as the telephone number can, although it can be replaced. Each time the telephone is used, it transmits its ESN to the MTSO by means of DTMF tones during the dialing sequence. The MTSO may be able to determine which ESNs are good or bad, thus individual numbers can be banned from use within the system. See also Cell and Cellular.

  2. Cable Modem Termination System. An element of DOCSIS (Data Over Cable Service Interface Specification), a project intended to develop a set of specifications for high-speed data transfer over cable television systems. CMTS comprises CMTS-DRFI (CMTS- Downstream RF Interface), CMTS-NSI (CMTS-Network Side Interface), and CMTS-URFI (CMTS-Upstream RF Interface) in order to provide two-way communications. See also CMTS-DRFI, CMTS-NSI, CMTS-URFI and DOCSIS.


Cable Modem Termination System-Downstream RF Interface. An element of DOCSIS (Data Over Cable Service Interface Specification), a project intended to develop a set of specifications for high-speed data transfer over cable television systems. At the head-end of the network, the CMTS-DRFI provides the interface between the cable modem system and the downstream RF (Radio Frequency) path, which terminates in the cable modem at the customer premise. It works in conjunction with the CMTS-URFI (CMTS- Upstream RF Interface) in order to provide two-day communications. See also CMTS-URFI and DOCSIS.


Cable Modem Termination System-Network Side Interface. An element of DOCSIS (Data Over Cable Service Interface Specification), a project intended to develop a set of specifications for high-speed data transfer over cable television systems. CMTS-NSI is the interface of the cable modem system at the head-end of the network; i.e., at the CATV provider's premise. CMTS-NSI provides the interface between the backbone cable system and the CATV provider's server complex. See also DOCSIS.


Cable Modem Termination System-Upstream RF Interface. An element of DOCSIS (Data Over Cable Service Interface Specification), a project intended to develop a set of specifications for high-speed data transfer over cable television systems. At the head- end end of the network, the CMTS-URFI provides the interface between the cable modem system and the upstream RF (Radio Frequency) path, which terminates in the cable modem at the customer premise. It works in conjunction with the CMTS-DRFI (CMTS- Downstream RF Interface) in order to provide two-day communications. See also CMTSDRFI and DOCSIS.


Cable Modem Telco Return Interface. An element of DOCSIS (Data Over Cable Service Interface Specification), a project intended to develop a set of specifications for high-speed data transfer over cable television systems. At the head-end of the network, the CMTRI provides the interface between the cable modem system and PSTN. See also DOCSIS.


A computer imaging term. A color model used by the printing industry that is based on mixing cyan, magenta , and yellow. It's also referred to as CMYK, with the K denoting black. The K was added after printers discovered they could obtain a darker black using special black colorants rather than by combining cyan, magenta, and yellow alone. See also CMYK.


A computer imaging term. A color model used by the printing industry that is based on mixing cyan, magenta, yellow and black (called "K.") It used to be called CMY. The K was added after printers discovered they could obtain a darker black using special black colorants (i.e. black ink) rather than by combining cyan, magenta, and yellow. CMYK is the basis of what's known now as "four-color" printing. But there is also five, six, seven and eight color printing, etc. Each of these "extra" colors are basically "colors" which are better printed as their own color rather than as a combination the basic three. Silver, copper, gold, aluminum, etc. are all printed traditionally as extra colors. They cannot be created by combining CMYK. Sometimes people are picky about the way their colors come out ” i.e. Coca Cola red ” so they may be printed with that color ink rather than combining CMYK. Typically a full color printing job requires passes under four printing presses ” each laying down C,M,Y and K. These extra colors ” silver, gold, copper , special colors ” will need additional printings by additional printing presses. Thus a color print job could easily become five, six or seven color print job. The most common full color print job we hear about is four color. But you see an awful lot of jobs that contain silver and copper and may be six color print jobs.


Complementary network.


  1. Cooperative Network Architecture.

  2. Centralized Network Administration is an AMP-defined architecture that consolidates all network electronics into a single closet instead of distributing them throughout the building. According to AMP, CNA saves money over the long haul because of reduced administration costs. Centralized Network Administration can be executed with optical fiber for runs up to 300 meters, with Category 5 unshielded twisted pair (UTP) if no user is more than 90 meters from the central cross-connected and equipment room. Compare with Distributed Network Administration.

  3. Customer Name and Address Bureau.


Caller ID with NAMe. See LNP (as in Local Number Portability). See SSN.


Canonical Name. The Canonical Name resource record, CNAME, specifies an alias or nickname for the official, or canonical, host name. Alias records assign an alternate hostname to a specific hostname. Both hostnames point at whatever IP address the primary hostname is assigned to. See also CNAME Records.

CNAME Records

Canonical Name Records. Records stored in a DNS (Domain Name Server) to create an alias to redirect traffic from one Internet domain name (i.e., URL, or Uniform Resource Locator) to another. See also A Records, MX Records, and URL.


Complementary Network Service. See Open Network Architecture.


  1. Calling Number Delivery. See Caller ID Message Format and Call Block.

  2. Calling Number Display. See also CLID.


Certified (local area) Network Engineer. When you graduate from Novell's third level class, you become a certified network engineer. CNEs are an elite group in the LAN industry. See also CCIE and MCSE.


Centre National d'Etudes de Telecommunication. The French organization that approves telecommunications products for sale in France.


Also called Auto Fax Tone, or Calling Tone. This tone is the sound produced by virtually all fax machines when they dial another fax machine. CNG is a medium pitch tone (1100 Hz) that lasts 1/2 second and repeats every 3 1/2 seconds. A fax machine will produce CNG for about 45 seconds after it dials. The CNG tone is useful for owners of fax/phone/modem switches. Such switches answer an incoming call. If they hear a CNG tone, they will transfer the call to a fax machine. If they don't, they'll transfer the call to a phone, answering machine or perhaps a modem. Depends on how they're set up. Some fax machines do not transmit a CNG tone with manually-dialed transmissions ” i.e. where the caller picked up the handset on the fax machine, dialed and waited for a high-pitched squeal before pushing his fax machine's "start" button. A manual dialed fax transmission will "fool" fax/voice switches. See CED and Facsimile .


Calling Number Identification Presentation. See CLIP.


Calling Number Identification Restriction. A wireless "cellular" term (GSM and PCS) for Call Block, also known as Calling Number Delivery (CND), in the wired world. See Call Block.


Calling Number Identification Services.


An ATM and SMDS (Switched Megabit Data Service) term. Customer Network Management. All activities that customers perform to manage their communications networks. SMDS CNM service enables customers to directly manage many aspects of the SMDS service provided by telecommunications carriers. See Customer Network Management.


Corporate Networking Officer, a term invented by William Y. O'Connor, CEO of Ascom Timeplex.


  1. Telephone company term for re-scheduling a telephone installation appointment because the "Customer is Not Ready."

  2. An ATM term. Complex Node Representation: A collection of nodal state parameters that provide detailed state information associated with a logical node.


The Corporation for National Research Initiatives, a Reston, VA-based not-for-profit organization that works with industry, academia, and government on national-level initiatives in information technology. It will host the initial operations of IOPS.ORG. "IOPS.ORG will play a key role in the healthy technical and operational evolution of the Internet as an increasingly important component of the economy," said CNRI President Robert Kahn.


Complementary Network Service. CNSs are basic services associated with end users' lines that make it easier for Enhanced Service Providers (ESPs) to offer them enhanced services. Some examples of CNSs include Call Forwarding Busy/Don't Answer, Three Way Calling, and Virtual Dial Tone. See Open Network Architecture.


Central Office. Pronounced "See-Oh". In North America, a CO is that location which houses a switch to serve local telephone subscribers. Sometimes the words "central office" are confused with the switch itself. In Europe and abroad, the words "central office" are not known. The more common words are "public exchange." But those words tend to refer more to the switch itself, rather than the site, as in North America. See also Central Office or Public Exchange.

CO Lines

These are the lines connecting your office to your local telephone company's Central Office which in turn connects you to the nationwide telephone system.

CO Location

See Colocation.

CO Simulator

A desktop device which pretends to act like a mini-central office. The smallest version will consist of two lines and two REJ-11 jacks. Plug a phone into both jacks . Pick up one phone. You hear dial tone. Dial or touchtone two or three digits. Bingo, the second phone rings. You pick up the second phone. You can have a conversation with yourself or with a machine ” like a voice processing system. Most central office simulators can simulate normal on-hook, off-hook, dialing, answering, speaking, etc. Some now can simulate caller ID features ” including the number of person calling.

Co-carrier Status

A relationship between a CLEC and an ILEC that affords each company the same access to and right on the other's network and provides access and services on an equal basis.

Co-channel Interference

Interference between signals transmitted in a given Radio Frequency (RF) channel in a particular cell and signals transmitted on the same RF channel in a different cell. A receiver that is in a position to receive from both cannot filter out the undesired signal and consequently the noise level at the receiver increases .


See Co-trenching.


Angelo Velez found this reference to co-directional in a technical student manual on a course on baseband equipment concerning source of signals, specifically on Transmit timing (DTE source), or terminal timing, etc. "The signal out of a DTE and into a DCE on pins 24/23 travels in the same direction as a transmit data bit. Therefore, this signal is known as the 'co-directional' transmit clock. The co-directional clock is generated by the DTE and is of the same accuracy as the DTE's reference; if the DTE is accepting the counter-directional clock (pins 15/16 in) as a reference, then the co-directional clock (24/23 out) will be synchronized with it."


  1. The ability of a someone who is not the local phone company to put their equipment in the phone company's offices and join their equipment to the phone company's equipment. See Colocation for a bigger explanation.

  2. Imagine you're running an ecommerce application that's important to your company, i.e. it's bringing in oodles of money. It's running on one or several servers which are physically in the same place. Now let's say you're manic about reliability. You may decide to outsource the physical hosting of one, some or all of these servers to a dedicated facility to make sure your servers are always up and running. These co-location facilities offer the customer a secure place to physically house their hardware and equipment as opposed to locating it in their offices or warehouse where the potential for fire, theft or vandalism is much greater. Most co-location facilities offer high-security , including cameras , fire detection and extinguishing devices, multiple connection feeds, filtered power, backup power generators and other items to ensure high-availability which is mandatory for all Web- based, virtual businesses. Also spelled Colocation.


You sell something I make. You make money on what you sell. In addition, I give you extra money ” what we call "co-marketing" funds. Co-marketing is misnamed. In the retail trade, it's called a "spiff" ” the extra money that a manufacturer pays the salesman for selling his product. See also Bounty.


Also known as co-digging. A form of colocation that involves multiple fiber- optic carriers to coordinate their cable implementation activities so that they share a single trench, and the cost and disruption associated with digging it. Local governments increasingly are requiring this level of coordination to minimize the disruption associated with multiple carriers digging up streets and roads . See also Colocation.


Customer Owned And Maintained telephone equipment. Similar to CPE, which stands for customer premise equipment, except that COAM equipment is a broader term, referring also to customer equipment outside of their immediate premises. It could refer to a customer-own microwave system, for example.

Coarse Wave Division Multiplexing



Unsolicited floppy disks or CD-ROMs, such as the ubiquitous American Online software, that arrive in one's mailbox too often.

Coasting Mode

In timing-dependent systems, a free-running operational timing mode in which continuous or periodic measurement of timing error is not available. In some systems, operation in this mode can be enhanced for a period of time by using clock or timing error (or correction) information obtained during a prior tracking mode to estimate clock or timing corrections to be made in the free-running mode.

Coated Filament

A vacuum tube filament coated with a metallic oxide to provide greater electron emission and longer life.


A protective material (usually plastic) applied to the optical fiber immediately after drawing to preserve its mechanical strength and cushion it from external forces that can induce microbending losses.

Coaxial Cable

A cable composed of an insulated central conducting wire wrapped in another cylindrical conducting wire. The whole thing is usually wrapped in another insulating layer and an outer protective layer. A coaxial cable has capacity to carry great quantities of information. It is typically used to carry high-speed data (as in connections of 327X terminals to computer hosts ) and in CATV installations.

Coaxial Lightning Suppressor

A device which grounds a coaxial cable shield and shorts surge voltages on the inner wire and the outer tubular wire.

Coaxial Switch

A switch used for disconnecting or re-routing signals on coaxial cables. See Transfer Switches.


Close Of Business.


Consortium of Brick and Mortars. This is not a real Consortium. It's an analysts' way of saying (and I quote) ""CoBAMs in any and all industries/sectors are here to stay provided they offer to be the de facto platform on which to conduct vertical industry B2B trade. Such CoBAMs will make life easier for the suppliers (?) by agreeing to do business on a common platform, business processes and interface. (A B2C example of this is to be found in Pegasus for Hotel reservation systems used by RedRoof Inns and Marriot etc.)" He also raised the antitrust flag to the extent that blood-from-turnip-squeezing takes place."


Common Business Oriented Language. A very popular computer programming language for business applications.


A misspelling of CORBA, Common Object Request Broker Architecture. See CORBA, Object Request Broker.

Cobweb Site

A Web Site that is so old and hasn't been updated so long that it has figuratively grown cobwebs.


Central Office Connection. Separately tariffed part of a T-1 circuit.


Condition of Continued Employment, which means follow the process or get approval to deviate; otherwise , find another job. In other words, "take my way or the highway ."

Cochannel interference

C/I. Cochannel interference refers to the interference caused between two cells transmitting on the same frequency within a network. Since cochannel interference is caused by another cell transmitting the same frequency, you can't simply filter out the interference. You can only minimize the cochannel interference through proper cellular network design. A cellular network must be designed to maximize the C/I ratio. The C/I ratio is the carrier-to-cochannel interference ratio. One of the ways to maximize the C/I ratio is to increase the frequency re-use distance, i.e. increase the distance between cells using the same set of transmission frequencies. The C/I ratio in part determines the frequency re-use distance of a cellular network.

Cockpit Effect

An acoustics phenomenon describing the difficulty we have in modulating our speech if there is background noise significant to impair our ability to hear ourselves . Under such circumstances, the lack of feedback causes us to speak loudly, and to alter our speech patterns. Also known as Lombard Speech, the cockpit effect particularly is a problem when using a cellular phone in an automobile to communicate with a voice processor employing speech recognition technology.

Cockpit Problem

Also known as "pilot error." A problem caused by the user's inability to operate a device or system correctly. A poorly-designed user interface often contributes to cockpit problems. Often, it's just a matter of the user's not taking the time to read the user manual, which would be largely unnecessary if the user interface were as "intuitive" as the manufacturer usually claims. Cockpit problems are the most common reason for calls to the "help desk." See also Help Desk, Idiot-Proof, Intuitive, and RTFM.


Entomologists have observed that cockroaches can change course as many as 25 times in one second, making them the most nimble animals known. Some people argue that politicians and lawyers can do the same thing.


Customer Owned Coin Operated Telephone. See also Clip on Toll Fraud.


Central Office Code Utilization Survey. The COCUS is an annual survey that seeks information on the number of central office (CO or NXX) codes currently assigned to telephone companies in America, as well as a forecast of the number of additional CO codes the companies will need over the next several years. The COCUS has been used by the industry for a number of years and is intended to provide an overall view of both present and projected CO code utilization, information that is critical for area code relief planning purposes. Although in prior years the regional CO Code Administrators performed this function, this year (1999) the COCUS is being conducted by the neutral North American Numbering Plan Administrator (NANPA), Lockheed Martin CIS.


An ATM term. Connection Oriented Data: Data requiring sequential delivery of its component PDUs to assure correct functioning of its supported application, (e.g., voice or video).


  1. As a verb, it means to write instructions in computer language. As a noun, it means software.

  2. In telecommunications, code is the system of dots and dashes used to represent the letters of the alphabet, numerals, punctuation and other symbols.

Code Bit

The smallest signaling element used by the Physical Layer for transmission on the fiber cable.

Code Bloat

Computer program code that has become swollen, i.e., bigger and more resource- intensive than it needs to be. Bloated code takes up more memory (both hard drive and RAM) than necessary, which also means that it takes an excessive amount of time to install, load, execute, transmit and work with. My classic example of code bloat is using Macromedia's Dreamweaver program to write web pages. For some reason I can't figure, it closes your choice of typeface at the end of each paragraph. Then opens each paragraph with code to indicate which typeface and which size. This is an example of the code it puts in at the beginning of every paragraph. What a waste. <font face="Verdana, Arial, Helvetica, sans-serif" size="-1">. These words are not necessary at the beginning of each paragraph. In true HTML, you only need this code at the beginning of the file ” until your typeface or size changes. See also Easter Egg.

Code Blocking

A switch's ability to block calls to a specified area code, central office code or phone number.

Code Blue

A PBX feature for hospital application. If a patient is in distress, he can simply knock the telephone handset off of the cradle. After a brief period, the PBX recognizes the lack of dialing activity and sends a "code blue" alarm to the nurses station. Nurses and doctors come running. People turn blue when they can't breathe ” hence the term.

Code Breaker

See Key and Key Holder.

Code Call Access

A very useful PBX feature. It allows attendants and extension users to activate, by dialing an access code followed by a two or three digit called code, customer-provided signaling devices throughout the premises. The signaling devices then issue a series of tones or visual coded signals corresponding to the called code. The called or paged party responds by dialing a meet-me answering code from any phone and is then connected to the paging party.

Code Coverage

Modern computer telephony systems are composed largely of software, or "code." Invariably this code has many different logic paths and options. During normal system usage, many code paths are used only infrequently, if at all, meaning that normal usage will really only test a small portion of the total system. Code coverage refers to the amount of the system code that has been accessed during the testing of the system. The greater the code coverage, the more code that has been tested. 100% code coverage means that all the code has been tested . The amount of code coverage that has been achieved is usually determined through the use of a code coverage tool. Code coverage tools are available for most computer operating systems. Code coverage is especially important for computer telephony applications because many features are only infrequently used or are turned on or off based on the user's class of service. Also, many features interact with other features and the use of one feature often turns off another. Functional anomalies frequently exist in little-used paths and feature interactions. Tests should be designed to make sure that all code paths have been accessed and are adequately exercised. This definition courtesy of Steve Gladstone, author of the book Testing Computer Telephony Systems, available from 212-691-8215.

Code Conversion

A process which converts the codes coming in from one network into codes that can be recognized on another network, such as converting from the Baudot code in a telex network to the ASCII code on the TWX network. Usually, the hardware will convert differences in transmission speed.

Code Division Multiple Access

CDMA, also called Spread Spectrum, is a name for a new form of digital cellular phone service. The idea is that each phone call is combined with a code which only one cellular phone plucks from the air. Business Week said CDMA works "by spreading all signals across the same broad frequency spectrum and assigning a unique code ” the company says one of 42 billion ” to each. The dispersed signals are pulled out of the background noise by a receiver which knows the code. This method, developed by a San Diego company called Qualcomm Inc. is very new. Much of the equipment to support it ” like the cellular switches ” has not yet been developed." CDMA is also being used by wireless PBXs. See CDMA for a longer and better explanation.

Code Excited Linear Prediction

CELP. An analog-to-digital voice coding scheme.

Code Independent Data Communication

Data communication mode using a link procedure associated with the character and not dependent on the set of characters or the code used by the data source.

Code Level

Number of bits used to represent a character.

Code Of Federal Regulations

CFR. CFR is a codification of the general and permanent rules published in the Federal Register. It is divided into 50 titles that represent broad areas subject to federal regulation. Title 47 of the CFR pertains to telecommunications and contains the rules covering Part 22 Common Carriers and Part 90 Private Carriers.

Code Violation

Violation of a coding rule; for example, the AMI coding rule is corrupted by a bipolar violation.

Code Word

When used in the context of the Reed-Solomon encoding, it refers to the 63, 6-bit symbols (378 bits) resulting from the encoding of 47 6-bit (282 bits) information symbols. This is done by appending 16 6-bit parity symbols.


Originally CODEC stood for CODer -DECoder, i.e. microprocessor chip. Now the PC industry thinks it stands for COmpression/DEcompression, i.e. an overall term for the technology used in digital video and stereo audio. The original CODEC (still in big use in today's telephony industry) converts voice signals from their analog form to digital signals acceptable to modern digital PBXs and digital transmission systems. It then converts those digital signals back to analog so that you may hear and understand what the other person is saying. In some phone systems, the CODEC is in the PBX and shared by many analog phone extensions. In other phone systems, the CODEC is actually in the phone. Thus the phone itself sends out a digital signal and can, as a result, be more easily designed to accept a digital RS-232-C signal.

CODEC Conversion

The back-to-back transfer of an analog signal from one CODEC into another CODEC in order to convert from one proprietary coding scheme (for instance, that used by CLI) to one used by another CODEC manufacturer (PictureTel, VTEL, GPT, BT, NEC, etc). The analog signal, instead of being displayed to a monitor, is delivered to the dissimilar CODEC where it is redigitized, compressed and passed to the receiving end. This is obviously a bi-directional process. Conversion service is offered by carriers such as AT&T, MCI and Sprint.

Coded Character Set

A set of unambiguous rules that establish a character set and the one-to-one relationships between the characters of the set and their coded representations.

Coded Image

A representation of an image in a form suitable for storage and processing.

Coded Orthogonal Frequency Division Multiplexing

COFDM. See 802.11a.

Coded Trunks

You buy several trunks. They hunt on. The main number is 555- 3000. If the main number is busy, the call goes to the next line. There are two types of "next lines." One type can have an actual number, like 555-3001, which you can call directly. The other can be a coded trunk with no actual number and which you can't call directly. It's better to have no coded trunks because it's hard to test coded trunks. You can't dial them directly. Actual dialable numbers are better.


An analog-to-digital converter that changes analog voice signals to their digital equivalents. See CODEC.


Also known as programmers or coders. Codernauts are on the ultimate quest for the perfect software.


Programs. It's an inside term used by hackers and heavy-duty grinders. Use it instead of "programs" like the Masons do with that secret handshake and those in the know will nod knowingly with respect. The majority will just nod sleepily.

Codial Office

CDO. A small central office designed for unattended operation in a distant community. Usually a community dial office is fairly small, rarely more than 10,000 lines.

Coding Theory

The mathematical theory describing how to encode data into streams of digital symbols at the transmitter and decode it at the receiver to maximize accuracy of data presented to user.


  1. Central Office Equipment; as in Central Office Equipment engineer.

  2. Central Office Engineer.

Coefficient Of Variation

A telephone company definition. Relates the standard deviation of a distribution to the mean of the distribution, usually as a percent. Example: If all of the busy hour , busy season loads for an office have a mean of 10,000 CCS and a standard deviation of 1000 CCS, the coefficient of variation is 10%.


Central Office Equipment Reports. A telephone company definition. A large scale computer software package which accepts Central office Engineering Data properly formatted by a Data Collection System (DCS), subjects these data to a series of validation tests, and produces final summarized reports designed to meet both administrative and engineering requirements.


Change Of Frame Alignment.


Coded Orthogonal Frequency Division Multiplexing (COFDM). See 802.11a.


  1. A person who is coughed upon.

  2. According to Dr. Bruce Ames, University of California at Berkeley, there are more than 1,000 chemicals in a cup of coffee. Of these, only 26 have been tested, and half caused cancer in rats.

  3. Frederick the Great of Prussia wanted to make coffee off limits to his subjects because of the huge sums of money that was going to foreign exporters. "My people must drink beer," Frederick demanded in a manifesto. Rumors flew furiously, including one that claimed coffee made people sterile. Acclaimed musician Johann Sebastian Bach disagreed vehemently with Frederick and his anti-coffee crowd . In retaliation, the composer wrote his "Coffee Cantata," published in 1732. Bach's composition told the story of a father who threatens to break off his daughter 's marriage plans unless she gives up her vile coffee- drinking habit. The girl agrees, but changes her mind when her mother and grandmother reveal that they have always been passionate , although secretive, coffee drinkers (and obviously not infertile). Bach himself was the father of 20 children.


Mexico's "COmision FEderal de Telecomunicaciones", analogous to the U.S. FCC, the regulatory governmental body that oversees deployment of networks and services, etc. Web site is

Cognitive Science

Cognitive science is the interdisciplinary study of the acquisition and use of knowledge. During the 1960s and 70s, cognitive science emerged from the fields of linguistics , psychology, computer science, philosophy, neuroscience and anthropology, as a multidisciplinary effort centered around a number of common problems using the computer as a research tool. In cognitive science, the computer has been used to simulate cognitive processes. It's been used widely in the marketing and advertising of products, particularly in the promotion of goods to children, who are highly susceptible to fast- paced suggestive advertising messages.


To come together firmly, to be cohesive, to coalesce, to hold together, join, unite, merge, especially small, discrete parts or granules.

Coherence Area

In optical communications, the area in a plane perpendicular to the direction of propagation over which light may be considered highly coherent .

Coherent Communications

In fiber optics, a communication system where the output of a local laser oscillator is mixed optically with a received signal, and the difference frequency is detected and amplified.

Coherent Interference

Any form of interference which is intelligible as a television picture. Typically either an offset ghost of a strong television picture or a ghost of a completely different picture mixed with a strong picture. See Non-Coherent Interference.

Coherence Length

The propagation distance over which a light beam may be considered coherent. See Coherent Light.

Coherent Light

Light signals emitted from lasers and some LEDs (Light Emitting Diodes) is coherent. Coherent light is made up of light waves that all travel in the same direction (spatial coherence), and are of the same frequency and phase (temporal coherence). Since the signals are locked in phase, their peaks and troughs are all in alignment, and the waves reinforce , or amplify, each other. This results in the intense , pure light beam that is characteristic of lasers. See also Incoherent Light, Laser Diode and LED.


  1. In electronics, a number of turns of wire, so wound as to afford inductance.

  2. In telecommunications a coil refers to a load coil. It's a voice- amplifying device for twisted-pair wire. A load coil is usually placed every 3000 feet past the CO. They are usually placed in vaults with twisted-pair splices. They should be removed for high speed data communications.

Coil Antenna

One consisting of one or more complete turns of wire. See Loop Antenna.

Coin Acceptor/Rejector

A mechanical or electromechanical device that checks and validates the coins deposited in a coin pay phone. They measure the coin's size and weight and steel content. These coin acceptor/rejector units transmit the value of the coin deposits to the processing part of a smart payphone or they signal the information to the telephone company central office via coded tones.

Coin Supervisory Trunk Group

A trunk group that lets a switchboard operator collect overtime monies due on coin phones and check for stuck coins.

Coin Telephone

A pay telephone that takes coins. The coin telephone was invented by William Gray, an American whose previous inventions included the inflatable chest protector for baseball players. Mr. Gray's first phone lacked a dial. Its instructions read:

"Call Central in the usual manner. When told by the operator, drop coin in proper channel and push plunger down."

In today's nomenclature , Mr. Gray's original phone is known as a post-pay coin phone. See also Payphone and several entries following it.


Computer Output to Laser Disk. A computer storage management term referring to hardware and software solutions which store, index and retrieve formatted computer output on various media, including optical disks. Large scale COLD systems can be used to manage and archive storage-intensive image files such as those associated with credit card bills, telephone bills, brokerage statements, or tax returns. COLD systems also are used to store compressed graphics and image data on high-powered Web servers for Internet access.

Cold Calls

See "How Are You Today?".

Cold Docking

Docking is to insert a portable computer into a base unit. Cold docking means the computer must begin from a power-off state and restart before docking. Hot docking means the computer can be docked while running at full power. See Cold Start.

Cold Fusion

Like alchemy or the perpetual motion machine, cold fusion is one of those scientific pipe dreams we wish would come true. Alas, the methods behind the claim that we could produce an almost infinite, magically efficient energy source by doing nuclear fusion at room temperature turned out to be inconsistent or fraudulent, depending on your level of skepticism. Still an underground network of cold fusion experimentation continues. Arthur C. Clarke is among the believers and funds Infinite Energy magazine. If the truth is out there, cold fusion is way out there.

Cold Standby

See Data Center.

Cold Start

Everything starts from scratch. The power to the computer or telephone system is turned off. Everything in the system's volatile memory is erased. A cold start may be needed on a microcomputer when something has happened to "lock up" the keyboard and the Reset button (if there is one) doesn't clear the problem completely. A Cold Start is also needed when you want to load a new operating system. When your phone system gives troubles you find hard to diagnose, turn it off, count to ten and turn it on. This cold boot to your phone system will often fix the problem, as it will typically do on a computer system.

Cold Transfer

An incoming phone call transferred without notice or explanation from the transferring party. "Someone in customer service cold transferred the call to me. By that point the guy was ready to crawl through the wires and kill somebody." I got this definition from Wired Magazine. In the telephone industry, they call the same thing "blind transfer."


A Rapid Application Development (RAD) system created by the Allaire Corporation of Cambridge, Mass, ColdFusion integrates browser, server and database technologies into Web applications. Cold Fusion Web pages include tags written in ColdFusion Markup Language (CFML) that simplify integration with databases and avoid the use of more complex languages like C++ to create translating programs. ColdFusion is the indus- try's leading cross-platform Web application server. With ColdFusion, Web developers can quickly develop and deliver a new generation of large-volume, transaction-intensive Web applications for everything from e-commerce to business automation and more.


A multimedia term. Collaboration involves two or more people working together in real-time, or in a "store-and-forward" mode. Applications will enable a group of people to collaborate in real-time over the network using shared screens, shared white- boards , and video conferencing. Collaboration can range from two people reviewing a slide set on line to a conference of doctors at different locations sharing patient files and discussing treatment options.

Collaboration Software

Software that lets two or more people do a task together. See Collaboration.


Two or more people working together on a project to share information and ideas, view suggestions, and make modifications. Computers can enable users to collaborate in real-time over a network or phone line using tools such as shared documents, shared whiteboards , and video conferencing, or time-efficient workflow such as document forwarding.

Collaborative Filtering

A new, fancy name for database mining. See database mining.

Collapsed Backbone

The backbone network connecting all network segments is collapsed ( shortened considerably), and contained within a hub, or chassis. In the case of 10Base-T (the most common local area network), the collapsed backbone is in the form of a collapsed bus (multipoint circuit) architecture. 10Base-T is a considerable improvement on traditional Ethernet, which involves a big, thick coaxial cable. 10Base-T effectively collapses a coax segment and places it in a chassis. Devices attach to the shared bus via UTP (Unshielded Twisted Pair), which is a much less expensive and much less troublesome medium than coax. Additionally, as the bus housed in a chassis, it is protected from both physical damage and sources of ambient EMI (ElectroMagnetic Interference). Think of it this way. Your original Ethernet consisted of as many as 1,024 devices (workstations, printers and servers, etc.). They connected to a big, fat, heavy, expensive coaxial cable that looked like an orange hose, and that could run as far as 2,500 meters through your reinforced ceilings and between the floors of your building. The orange hose was a big electrical bus, or multipoint circuit. Every frame of Ethernet data traveled in both directions along the hose, and passed every attached device. Only one device could transmit across the hose at a time, or data collisions occurred. The devices connected to the hose through vampire taps that looked like big, ugly alligator clips (those of you who were hippies in the 1960's will remember those). The vampire taps had a big sharp tooth that pierced the hose to establish a mechanical and electrical connection with the center coax conductor. If you disconnected a device and removed the vampire tap, the cable picked up noise through the hole you left in the cable. You replaced the orange hose and the vampire taps with a bunch of tiny hubs about half the size of a VCR (but with a clock that doesn't blink 12:00). Each hub contains a collapsed backbone, which is a tiny electrical bus that works like a small segment of the orange hose. Each hub and each collapsed backbone support a workgroup of perhaps 8-24 individuals with a common set of interests like accounting (which isn't very interesting) or engineering (which is very interesting) or sales (which is scary). Every user's workstation connects to the collapsed bus through twisted pair and a connector that looks much like your telephone wire and plug, only a little bigger. (It's called an RJ-45). The workgroup hubs are connected together by the same kind of wires and plugs, at least if they are close together. All together, the hubs, the tiny busses , and the little wires and plugs cost a lot less to buy and connect than the orange hose and vampire taps. They also are a lot easier on the eye. Also, they pass data by only a small number of attached devices within the workgroup, unless you need to communicate with a device attached to another hub. That means that the opportunity for congestion is much less. Think about the electrical wiring in your house. Your breaker box contains a collapsed bus to which the circuit breakers connect. Thin insulated wires from the circuit breakers connect to electrical outlets. It's much less expensive and much prettier to do it that way, rather than to run a thick, expensive and dangerous ( high-voltage ) electrical bus all around the house so that you can tap your lamps and appliances into it. See also 10Base-T, Ethernet, and Hub.

Collapsed Bus

See Collapsed Backbone.

Collapsed Ring

A SONET term. SONET optical fiber systems are deployed in a ring architecture, with two or four fibers for redundancy and, therefore, network resiliency. A collapsed ring topology is one in which the ring fibers are laid in the same fiber bundle. If the fiber bundle is cut, and all fibers in the ring are cut, the ring collapses. A collapsed ring is a very bad thing. See also SONET.


A financial term that occurs in conjunction with takeover bids. When AT&T offered to buy Comcast in the Spring of 1999, it offered Comcast shareholders a "collar." The collar was a guarantee that if the value of AT&T's stock dropped, AT&T would cover up to a 10% decline with additional cash.

Collateral Duties

A call center term. Non-phone tasks (e.g., data entry) that are flexible, and can be scheduled for periods when call load is slow.

Collect Call

A telephone call in which the called person pays for the call. The person calling calls a number and asks that the call be made "collect." Sometimes collect calls are handled by live operators, sometimes by machines. In a collect call, the phone company has to get some authorization from the person receiving the call that he will pay for it. This may be done by saying "Yes" or hitting a button a touchtone phone.

Collected Digits

The keys a caller presses in response to menu choices or other requests for information, such as account number, made by a Voice Response Unit.

Collector Ring

Metallic ring generally on the armature of a generator in contact with brushes for completing the circuit to a rotating member.


To make light rays parallel. The process of collimation is accomplished by a collimator. See Collimation.


The process by which a divergent or convergent beam of electromagnetic radiation is converted into a beam with the minimum divergence or convergence possible for that system ( ideally , a parallel bundle of rays). In the context of telecommunications, collimation generally is used in fiber optics. In fiber optic transmission systems, a diode laser couples to an optical fiber in order to present light signals to the clear center of the core of the fiber through a focusing lens. The focused light signals naturally criss-cross and dance around the edges of the optical fiber, which causes the individual light pulses to lose their shape. This is due to a phenomenon known as "modal dispersion," as different portions of the light signal take different paths, or "modes," as the transverse the fiber. Modal dispersion results in what is known as "pulse dispersion," which describes the overlapping of the individual light pulses at the distant, or receiving, end of the fiber. The bottom line is that the light detector may not be able to distinguish between the individual pulses, and the integrity of the datastream is compromised. Collimation mitigates this effect by lining up the highly-divergent elements of the light beam so that it travels in parallel, rather than criss-crossing. The resulting light beam is relatively uniform, which improves the integrity of the datastream over a distance. Collimation is accomplished by coupling lenses known as "collimators," which fit inside the steel barrels of optical fiber connectors. Collimators can be positioned at the light source, the coupling point between the light source (i.e., transmitter) and the optical fiber, and the coupling point between the optical fiber and the light detector (i.e., receiver). See also Fiber, Modal Dispersion, Pulse Dispersion.


A collimator is an assembly that is used to straighten and make parallel diverging light as it exits a fiber. See Collimation.

Collinear Antenna

A cellular car antenna which looks like a pigtail , because it has a little curlicue in the middle. The curlicue is not a spring, but a clever bit of electromechanical magic known as a phasing network, which allows the antenna to boost the effective power of the transmitter's signal. Typically a collinear cellular car antenna is 13 inches high.


The result of two workstations (or PCs) trying to use a shared transmission medium (cable) simultaneously ” a local area network, for example. The electrical signals, which carry the information they are sending bump into each other. This ruins both signals and both will have to re-transmit their information. In most systems, a built in delay will make sure the collision does not occur again. The whole process takes fractions of a second. Collisions in LANs make no sound. Collisions do, however, slow a LAN down. See Aloha, Collision Detection, Collision Domain, Contention and CSMA/CD.

Collision Detection

The process of detecting that simultaneous (and therefore damaging ) transmission has taken place. Typically, each transmitting workstation that detects the collision will wait some period of time and try again. Collision detection is an essential part of the CSMA/CD access method. Workstations can tell that a collision has taken place if they do not receive an acknowledgement from the receiving station within a certain amount of time (fractions of a second). See Aloha, Collision Domain, Contention and Ethernet.

Collision Domain

Today's most popular local area networking topology is Ethernet. To communicate, Ethernet uses the Carrier Sense Multiple Access/Collision Detect (CSMA/CD) protocol. What this means is that each computer listens to what's going on on the network when it wants to transmit. If no other computer is talking, it will start to send its message. If two computers start to send their messages at the same time, a collision of the messages they're trying to send happens and both stop for a random amount of time and then try to transmit their messages again after that period elapses. This way of controlling traffic on a local area network works well in a lightly-trafficked network. But as traffic builds up (as it always does), it's a problem. Think of a telephone party line. The more people are on, the harder for everyone to get to speak. To control this problem we can break our one-wire Ethernet network into pseudo-separate networks ” what are known as collision domains. We insert some intelligent electronics at the entrance to every pseudo-network. That electronics acts as an intelligent traffic cop, keeping traffic that is meant for Joe's PC which resides on subnetwork A away from all the other subnetworks. In this way, we have fewer machines trying to use one wire (i.e. the whole Ethernet LAN), and thus there'll be fewer collisions. Clearly the equipment to do is more costly than an Ethernet hub (which is, in essence, a giant teleconference bridge), since this equipment has to be intelligent, recognizing which messages are to go where. The first equipment that was tried was Bridges. Bridges did not change the packets at all but learned what machines were on which sides and let traffic flow when it needed to. Later on, Bridges were replaced with routers. Routers are able to look at where packets are coming from and where they are going and determine which way to send them on. (Remember that traffic on any particular segment goes to the entire segment.) These routers would act as gatekeepers to allow only the traffic destined outside the segment to pass through. Multiple network cards in the network server allow the server to function as a router and perform these functions without much cost or overhead. Routers have more intelligence then bridges and can broadcast information to other routers to find the best possible route for a particular data conversation. Routers do modify your packet in terms of the addresses so it can change the path of the packet. That also adds more latency (delay) as now each packet has more processing done to it as it goes through the network.

A few years ago switches came on the market. Switches replaced some or all of the hubs and broke the network into segments. Switches are really a marketing term for bridges. They store and forward the packets without modification and divide your network into multiple segments. The big buzz right now is level 3 switches. Level 3 switching refers to the layer of the OSI model also known as the networking layer. This adds intelligence to the switch to see where the packet is coming from and going to. This happens to be the same way that routers work. In a lightly loaded network switches will slow things down because of latency in getting the packet processed . They make it more difficult to monitor your network using a protocol analyzer. They can cause timeout or expiration issues if you add too many hops into your network. See Ethernet.

Collision Window

The time it takes for a data pulse to travel the length of the network. During this interval, the network is vulnerable to collision.


See Colocation, which is my preferred way of spelling this term.


Colation occurs when a competing local phone company (often called a CLEC, Competitive Local Exchange Carrier or an Other Common Carrier) locates (i.e. puts) its switches within an incumbent local exchange carrier's (ILEC) central office. An ILEC is the is the dominant phone carrier within a geographic area as determined by the FCC. Section 252 of the Telecommunications Act 1996 defined Incumbent Local Exchange Carrier as a carrier that, as of the date of enactment of the Act, provided local exchange service to a specific area. The Act provided that the Commission may treat "comparable carriers as incumbents" if they either "occupy a position in the market for telephone exchange service within an area that is comparable to the position occupied by the ILEC or such a "carrier that has substantially replaced an ILEC...." or if "such treatment is consistent with the public interest..."

There are basically two types of colocation ” adjacent / physical, and virtual. Adjacent and physical are the same. They mean that your equipment sits in the same building as the ILEC's switching and cable termination equipment. Typically it sits in a locked cage. Only the CLEC and its personnel have the key. Access to that equipment is negotiated between the ILEC and the CLEC through an interconnection agreement. The CLEC will have 24x7 access to it because they have to maintain it for customers who expect service 24 hours a day seven days a week. The concept of colocation ” at this stage a peculiarly North American idea ” came about through the Telecommunications Act of 1996. U.S. It was a federal bill signed into law on February 8, 1996 "to promote competition and reduce regulation in order to secure lower prices and higher quality services for American telecommunications consumers and encourage rapid deployment of new telecommunications technologies." The Act required local service providers in the 100 largest metropolitan areas of the United States, the Baby Bells, to implement Local Number Portability by the end of 1998. The Act also allowed the local regional Bell operating phone companies into long distance once they had met certain conditions about allowing competition in their local monopoly areas ” thus the concept of colocation. That's what the word colocation means. OK, now to the real stuff ” how to spell it. Several readers have complained that in previous editions of this dictionary it was spelled "colocation." They point out that their non-technical English language dictionaries spell it collocation ” with two "l"s. Random House Dictionary says that back in 1505-15 the word collocation appeared and was based on the Latin collocatus, which derives from collocare. But Random House also includes a spelling from the era of 1965-1970, which it spells colocate and defines as to locate or be located in jointly or together, as two or more groups, military units, or the like; share or designate to share the same place. My preference is colocation, since it seems to me a logical shortening of co-location. But I'm not arguing. Choose which spelling you'd like. See also Carrier Hotel, CLEC, ELEC, ILEC, and Virtual Colocation.

Collocation Cage

A cage in a central office that is erected by the ILEC and rented to a CLEC. CLEC personnel can access and maintain the equipment in the cage.


Did you ever notice a paragraph at the end of a book describing the type- faces used, the production methods, and so forth? That little paragraph is called a colophon.



Color Code

A color system for circuit identification by use of solid colors, contrasting stripes , tracers, braids, surface marking, etc.

Color Difference Signal

The first step in encoding the color television signal. The color difference signals are formed by subtracting the luminance information from each primary color: red, green or blue. Color difference conventions include the Betacam format, the SMPTE format, the EBU-N10 format and the MII format.

Color Model

A technique for describing a color (see CMY, HSL, HSV, and RGB).

Color Picture Signal

The electrical signal which represents complete color picture information excluding all the synchronizing signals.

Color Space Inversion

A video compression technique which reduces the amount of color information in each of a series of still images. It is based on the fact that the human eye is not highly sensitive to variations in color.

Color Subcarrier

The 3.579545 MHz subcarrier that carries the chrominance information of the television signal. This signal is superimposed on the luminance level. Amplitude of the color subcarrier represents saturation and phase angle represents hue.

Color Temperature

Selecting the color temperature determines the overall color cast of a display. 9,300 degrees Kelvin is good in environments lit by fluorescent lights, 6,500 degrees Kelvin is preferable under incandescent light.


Cell Site On Light Truck. A temporary, mobile wireless antenna base station installed on a light truck. The truck is parked at a location in order to temporarily increase either the coverage or the traffic capacity of the wireless network. I first heard the expression when I heard that BellSouth was using them to help expand its communications capacity in Atlanta for the 1996 Summer Olympics. See also COW (Cell Site on Wheels).


A mineral that is found in eastern Congo, Africa and Australia. Coltan is three times heavier than iron, slightly lighter than gold. Once coltan is refined it becomes tantalum, a metallic element that is a superb conductor of electricity, highly resistant to heat. Tantalum powder is a vital ingredient in the manufacture of capacitors. Capacitors made of tantalum can be found inside almost every laptop, pager, personal digital assistant and cell phone.


A database definition: The logical equivalent of a field, a column contains an individual data item within a row or record.


  1. Continuation of Message: An indicator used by the ATM Adaptation Layer to indicate that a particular ATM cell is a continuation of a higher layer information packet which has been segmented.

  2. Component Object Model. COM is Microsoft's cornerstone of its ActiveX platform. COM is a language independent component architecture (not a programming language). It is meant to be a general purpose, object-oriented means to encapsulate commonly used functions and services. The COM architecture provides a platform independent and distributed platform for multi-threaded applications. COM also encompasses everything previously known as OLE Automation (Object Linking and Embedding). OLE Automation was originally for letting higher level programming languages access COM objects. An object is a set of functions collected into interfaces. Each object has data associated with it. The source of the data itself is called the data object. With COM, the transfer of the data itself is separated from the transfer protocol. See ActiveX and Windows Telephony.

  3. A type of Internet domain assigned to URLs which are business or commercial entities (for example, There is also .edu, .gov, .net, and .org. See Domain.

COM Port

The communications port on a PC, a workstation, server, or other DTE (Data Terminal Equipment). This port is sometimes referred to as the serial, RS-232, DB-9 or DB- 25 port (depending on if it has nine or 25 pins).

Combat Net Radio

CNR. A radio operating in a network, providing a half-duplex circuit employing a single radio frequency or a discrete set of radio frequencies (frequency hopping ). Combat net radios are primarily used for command and control of combat, combat support, and combat service support operations between and among ground, naval, and airborne forces.

Combination Network

A network designed to combine two or more input channels into one output channel. See Combiner.

Combination System

An alternative to upgrading older telephone equipment, combination systems make it possible to add network-based features to an equipment- based telephone system.

Combination Trunk

A central office trunk circuit that supports both incoming and outgoing traffic. Traditionally, PBX trunks are directional. That is to say that they are incoming only, outgoing only, or combination. More recently, the individual channels in a T-1 PBX trunk can be defined in terms of their directional nature, with some being defined as DID (Direct Inward Dialing), some as DOD (Direct Outward Dialing), and some as combination (both incoming and outgoing). See also DID, Direct Inward System Access, and DOD.

Combined Distribution Frame

CDF. A distribution frame that combines the functions of main and intermediate distribution frames . The frame contains both vertical and horizontal terminating blocks. The vertical blocks are used to terminate the permanent outside lines entering the station. Horizontal blocks are used to terminate inside plant equipment. This arrangement permits the association of any outside line with any desired terminal equipment. These connections are made with equipment. These connections are made with twisted pair wire, normally referred to as jumper wire, or with optical fiber cables, normally referred to as jumper cables. In technical control facilities, the vertical side may be used to terminate equipment as well as outside lines. The horizontal side is then used for jackfields and battery terminations.

Combined Station

MDLC station containing both a primary and a secondary and used in asynchronous balanced mode.


A network for putting two or more frequency bands or channels together for transmission along a single line.


AT&T's old numbering system for telecom equipment, replacing older KS-prefix numbers, that supplements standard industry part designations. Comcode No. 102092848 is touchtone Princess phone with a transparent plastic housing. See also KS Number.


Comdex is, or was once, the largest computer show of the year. It gets its name from COMputer DEalers eXposition. It's held twice a year in the U.S. The biggest and main U.S. show is in Las Vegas in November. Nearly three million people have attended COMDEX Fall since 1979 when the show was launched with a first-year attendance of 4,000. Peak attendance in the late 1990s was 250,000. The second Comdex show every year in the U.S. is in the Spring and typically moves between Atlanta and Chicago. IBM first showcased their new PC during Comdex 1981. Comdex is now held in 19 cities in 14 countries on every continent except Antarctica.


The Network Reliability ComForum is a gathering of senior telecommunication industry executives and government officials that serve on the Network Reliability Council. The ComForum meets to report on the Council's findings. See USITA.

Comfort Tone

Michael Boom heard this one at an engineering meeting at Ascend Corporation, where an engineer was describing digital phone lines. It turns out that many phone connections are so clean now that there is no background noise at all. The phone customer, hearing absolutely nothing, believes the connection is broken and hangs up. The solution? A "comfort tone." A comfort tone is very low-level synthesized white noise deliberately added to a digital line to give a comforting "hiss" to the connection. It assures customers that there is indeed a connection and gives the voices on the other end that slightly distant quality the person making the telephone call expects to hear.


COMunications INTelligence.

Comite Consultatif International des Radiocommunications

CCIR. The agency responsible for the international use of the radio spectrum. Effective in 1993, the CCIR is now known as the International Telecommunications Union ” Radio. ITU-R and ITU-T form the International Telecommunications Union. See ITU for a much longer explanation.

Comma-Free Code

A code constructed such that any partial code word, beginning at the start of a code word but terminating prior to the end of that code word, is not a valid code word. The comma-free property permits the proper framing of transmitted code words, provided that: (a) external synchronization is provided to identify the start of the first code word in a sequence of code words, and (b) no uncorrected errors occur in the symbol stream. Huffman codes (variable length) are examples of comma-free codes.

Comma Separated Values

See CSV.


See Command Set.

Command And Control

C2. The exercise of authority and direction by a properly designated commander over assigned forces in the accomplishment of the mission. Command and control functions are performed through an arrangement of personnel equipment, communications, facilities, and procedures employed by a commander in planning, directing, coordinating, and controlling forces and operations in the accomplishment of the mission.

Command And Control System

The facilities, equipment, communications, procedures, and personnel essential to a commander for planning, directing and controlling operations of assigned forces pursuant to the missions assigned. See Command, Control and Communications.

Command Buffer

A segment of memory used to temporarily store commands. The command buffer only holds a copy of the last command issued.

Command Conference System

A conference calling arrangement in a Northern Telecom PBX which allows a designated phone to originate a conference to and between a group of PBX extensions. Any phone that is busy when the conference begins is automatically connected to the conference as soon as that phone becomes free.

Command, Control And Communications

C3. The capabilities required by military commanders to exercise command and control of their forces.

Command Interpreter

The operating system that controls a computer's shell. The command interpreter for MS-DOS is COMMAND.COM. The command interpreter for Windows is WIN.COM.

Command Line

The line on the screen, in MS-DOS, where the cursor is. The command line is where you enter MS-DOS commands.

Command Line Interpreter

CLI. A Rolm user interface to the CBX software and used for things like testing.

Command Net

A communications network which connects an echelon of command with some or all of its subordinate echelons for the purpose of command control. See C2 and C3.

Command Path

The list of path names that tells MS-DOS where to look for files that aren't in the current directory.

Command Port

In network management systems an interface used to monitor and control the system.

Command Processor

The MS-DOS program, COMMAND.COM, that contains all MS-DOS's internal commands, like DIR, ERASE and REName.

Command Prompt

The MS-DOS command prompt appears on the screen as the default drive letter followed by a greater than > sign. The command prompt lets you know MS-DOS is ready to receive a command.

Command Pulses

Pulses transmitted from a control device (such as a dialer) to either a direct control switch or to an intermediate device (e.g., a pulse register).

Command Response

C/R. A Frame Relay term defining a 1-bit portion of the frame Address Field. Reserved for the use of FRADs, the C/R is applied to the transport of data involving polled protocols such as SNA. Polled protocols require a command/response process for signaling and control during the communications process.

Command Save

A Rockwell ACD term. The introduction of a new demand command defines up to 10 commands per terminal position to enhance the productivity of both IST and non-IST supervisors.

Command Set

In computer telephony, a command set is a collection of special software instructions that do special jobs. These software instructions are often called function calls. For example, the command M_Make_Call (plus parameters) tells Northern's Norstar phone system to have telephone set number 21 dial a phone number. Northern's Norstar and other open phone systems (those that can be commanded by an external computer which you and I can program) all have their own command sets. Each command set is made up of function calls with funny words like M_Make_Call. Typically those function calls work in C, a common software language. A function call will reach into the specialized driver that controls the phone system (an exact analogy is the driver that drives a laser printer) and get the phone system to do something. A programmer must use these function calls if he/she wants to control the phone system from software. Exactly how M_Make_Call works is typically not revealed to the programmer. That keeps the manufacturer's technology proprietary and secret. It also saves the programmer the time and expense of writing the driver.

The program that carries out MS-DOS commands. The generic term for this program is command interpreter.

COMMDesk Banker

A communications software package offered by MCI International that provides all the capabilities of COMMDesk, plus a security feature essential for financial transactions.

COMMDesk Manager

An MCI definition. A communications software package designed to run on an IBM PC/XT/AT or compatible that gives the user full access to all MCI International and MCI communications services.


Let's say you're writing some software ” whether it be something as simple as an HTML web site or something as complex as C++. You'll always want to put some words inside your code so that you (and others who come after you) will understand what you were trying to do. In the HTML "language," such remarks are called "comments." (In other languages they're called other things, like "remarks." You'll recognize comment lines in HTML because they look like this:

 <! Your comment in text goes here > 


A not-for-profit industry association that works to accelerate the development of electronic commerce. In conjunction with the World Wide Web Consortium (W3C), Commercenet developed the Joint Electronic Payments Initiative (JEPI), an E- Commerce standard. The approximately 500 members of CommerceNet include leading banks, telecommunications companies, VANs, ISPs, online service, software and services companies, as well as major end users. See also Electronic Commerce and JEPI.

Commercial Building Telecommunications Wiring Standard

In 1985, the Electronic Industries Association undertook the task of developing a standard for commercial and industrial building wiring. Approved and published on July 9, 1991, the EIA/TIA-568 "Commercial Building Telecommunications Wiring Standard" defines a generic wiring system which will support a multiproduct, multivendor environment and which will have a useful life of over 10 years. The EIA/TIA standard is based on star topology in which each workstation is connected to a telecommunications closet situated within 90 meters of the work area. Backbone wiring between the communications closets and the main cross-connect is also organized in a star topology. However, direct connections between closets are allowed to accommodate bus and ring configurations. Distances between closets and the main cross-connect are dependent on backbone cable types and applications. Each workstation is provided with a minimum of two communications outlets (which may be on the same faceplate). One outlet is supported by a four-pair, 100-ohm unshielded twisted-pair (UTP) cable. The other may be supported by (a) an additional four-pair UTP cable, (b) a two-pair, 150 ohm shielded twisted pair (STP) cable or (c) a two-fiber 62.5 /125 micron fiber optic cable. For more on cabling and cabling components , see Category OF Performance.

Commercial Internet

The part of the Internet provided by commercial services. Allows business usage of the Internet without violating the appropriate usage clause of the National Science Foundation NETwork (NSFNET), who actually runs the Internet.

Commercial Internet Exchange Association

This is a non-profit trade association for public data internetworking service providers.

Commercial Mobile Radio Service

CMRS. CMRS is an FCC designation for any carrier or licensee whose wireless network is connected to the public switched telephone network and/or is operated for profit.

Committed Access Rate

See CAR.

Committed Burst Size

Bc. A Frame Relay term defining the maximum data rate that the carrier agrees to handle over a subscriber link under normal conditions. See also Offered Load, Committed Information Rate, Discard Eligibility, and Excess Burst Size.

Committed Information Rate

CIR. A Frame Relay term identifying the user's commitment to a certain average maximum data transmission rate. The monthly bill a customer receives may include at least two elements, depending on the pricing algorithm employed by the carrier; those charges can include a charge for the CIR and a surcharge for usage above the CIR. Usage above the CIR may be measured in terms of the Burst Size and Burst Interval. Usage above the CIR may be subject to discard in the event of network congestion. In the early days of frame relay when few people were using the service, customers were opting for a low Committed Information Rate, thus keeping their bills low, but knowing that they could always get their transmissions through ” because there were few other people on the service. As the service got more popular, many customers found they had to hike their Committed Information Rate if they wanted to get their information through. For a more technical explanation, see CIR.


See Sensitivity Training.

Common Audible

The same as Common Bell. Ringer wiring is such that ringing occurs on more than one CO or PBX line.

Common Audible Ringer

A loud ringer connected to a phone line in a noisy area. When the phone rings, the loud ringer also rings.

Common Battery

A battery (or several batteries) that acts as a central source of energy for many pieces of equipment. A common battery provides 48 volts of power to a central office switch and to all the phones connected downstream.

Common Battery Signaling

A system in which the signaling power of a telephone is supplied by the battery at the servicing switchboard. Switchboards may be manual or automatic, and "talking power" may be supplied by common or local battery.

Common Bell

A bell or ringer which sounds when any of the lines terminating on that phone rings. A term harking back to 1A2 key system days.

Common Business Line

CBL. An option with 800 Service that has been replaced by 800 Business Line.

Common Carrier

A company that furnishes communications services to the general public. It is typically licensed by a state or federal government agency. A common carrier cannot refuse to carry you, your information or your freight as long as you conform to the rules and regulations as filed with the state or federal authorities. See Other Common Carrier.

Common Carrier Bureau

A department of the Federal Communications Commission responsible for recommending and implementing regulatory policies on interstate and international common carrier (voice, video, data) activities.

Common Channel Interoffice Signaling

CCIS. A way of transmitting all signaling information for a group of trunks by encoding that information and transmitting it over a separate channel using time-division digital methods. By transmitting that signaling information over a separate channel, CCIS saves huge long distance bandwidth, which in the past was used to switch calls across the country only to find a busy signal and then come all the way back again to signal the calling party a busy. For the biggest explanation of common channel signaling, see Signaling System 7. See also MTP, SCCP, ISUP, ISDN and TCAP.

Common Channel Signaling

This is a Bellcore definition: A network architecture which uses Signaling System 7 (SS7) protocol for the exchange of information between telecommunications nodes and networks on an out-of- band basis. It performs three major functions:

  1. It allows the exchange of signaling information for interoffice circuit connections.

  2. It allows the exchange of additional information services and features, e.g. CLASS, database query/response, etc.

  3. It provides improved operations procedures for network management and administration of the telecommunications network. For the biggest explanation of common channel signaling, see Signaling System 7. See also ISDN, ISUP, MTP, SCCP, STP and TCAP.

Common Channel Transit Exchange

An intermediate exchange where networking of common channel signaling systems occurs.

Common Control

A method of telephone switching in which the central logic system (or control equipment) is responsible for routing calls through the network. The control equipment is connected with a given call only for the period required to accomplish the routing function. In other words, the common control equipment is associated with a given call only during the periods required to accomplish the control functions. All crossbar and electronic switching systems have common control.

Common Control Equipment

An automatic switching system that makes use of common equipment to establish a connection. Once the connection is made, the common control equipment is available to establish another connection.

Common Control Switching Arrangement

CCSA. An AT&T offering for very big companies. Those big companies can create their own private networks and dial anywhere on them by dialing a standard seven digit number, similar to a local phone number. The corporate subscriber rents private, dedicated lines and then shares central office switches. CCSA uses special CCSA software at the central office.

Common Costs

Costs of the provision of some group of services that cannot be directly attributed to any one of those services.

Common Equipment

In telephone systems Common Equipment are items that are used by several or all phones for processing calls. On a key system, the device that permits a light on any instrument to flash on and off may be Common Equipment when used to control all lights on all instruments.

Common Gateway Interface


Common Intermediate Format

A videophone ISDN standard which is part of the ITU-T's H.261. It produces a color image of 352 by 288 pixels. The format uses two B channels, with voice taking 32 Kbps and the rest for video.

Common Language Code

Codes used to ensure uniform abbreviation of equipment and facility names, place names, etc.

Common Language Location Identification Code

CLLI. The CLLI code is an 11 character mnemonic code used to uniquely identify a location in the United States, Canada or other countries. These codes are known as CLLI or 'Location Codes' and may be used in either a manual or mechanized record keeping system. For a bigger explanation, see CLLI Code. See also CFA.

Common Mail Calls

New APIs (Application Programming Interfaces) from Microsoft which allow you to move information around your various mail services ” the ones on your LAN, on your wireless pager, etc.

Common Mode

The potential or voltage that exists between neutral and ground. Electronic equipment requires this to be as close to 0 volts as possible or not to exceed 1/2 volt. For AC power systems, the term common mode may refer to either noise or surge voltage disturbances. Common mode disturbances are those that occur between the power neutral (white wire) and the grounding conductor (green wire) Ideally, no common mode disturbances should exist since the neutral and grounding wires are always connected at the service distribution panel in most countries. However, unwanted common mode disturbances exist as a result of noise injection into the neutral or grounding wires, wiring faults, or overloaded power circuits. Modern computers are quite immune from common mode noise. Common mode noise is frequently mistakenly confused with inter-system ground noise, a distinct problem which frequently causes computer damage and data errors. See Common Mode Interference.

Common Mode Interference

  1. Interference that appears between signal leads, or the terminals of a measuring circuit and ground.

  2. A form of coherent interference that affects two or more elements of a network in a similar manner (i.e., highly coupled ) as distinct from locally generated noise or interference that is statistically independent between pairs of network elements.

Common Mode Rejection Ratio

CMRR. The ratio of the common mode interference voltage at the input of a circuit to the corresponding interference voltage at the output.

Common Mode Transmission

A transmission scheme where voltages appear equal in magnitude and phase across a conductor pair with respect to ground. May also be referred to as longitudinal mode.

Common Mode Voltage

  1. The voltage common to both input terminals of a device.

  2. In a differential amplifier , the unwanted part of the voltage between each input connection point and ground that is added to the voltage of each original signal.

Common Object Request Broker Architecture


Common Open Policy Service


Common Path Distortion

Common path distortion is the interference of return-path signaling caused by the forward path.

Common Peer Group

An ATM term. The lowest level peer group in which a set of nodes is represented. A node is represented in a peer group either directly or through one of its ancestors .

Common Return

A return path that is common to two or more circuits and that serves to return currents to their source or to ground.

Common Return Offset

The dc common return potential difference of a line.

Common sense

"Why would any person want to use this ungainly and impractical device when he can send a messenger to a local telegraph office and have a clear written message sent to any large city in the United States?" Excerpt from a report to the President of Western Union written by the committee charged with investigating the potential purchase of Bell's telephone patent for $100,000. Western Union rejected the opportunity, and of course, passed on one of the greatest business opportunities in the history of business.

Common Trunk

In telephone systems having a grading arrangement, a trunk accessible to all groups of the grading.

Common User Circuit

A circuit designated to furnish a communication service to a number of users.

Common User Network

A system of circuits or channels allocated to furnish communication paths between switching centers to provide communication service on a common basis to all connected stations or subscribers.


  1. A quality that applies to material or systems:

    1. possessing like and interchangeable characteristics enabling each to be utilized, or operated and maintained by personnel trained on the others without additional specialized training;

    2. having interchangeable repair parts and/or components;

    3. applying to consumable items interchangeably equivalent without adjustment.

  2. A term applied to equipment or systems that have the quality of one entity possessing like and interchangeable parts with another equipment or system entity.

Communicating Applications

A General Magic term. An application whose design presupposes the user's desire to send and receive messages. For a Personal Intelligent Communicator to be effective, it needs to be equipped with a suite of communicating applications. All Magic Cap applications are built to communicate.

Communicating Applications Platform

A General Magic term. The Cap in Magic Cap. Software on which Personal Intelligent Communicators are based. It is designed to make it easy for developers to create communicating applications and services. Magic Cap can run on dedicated devices as well as other computer operating systems.

Communicating Applications Specification

A facsimile specification. See CAS 2.0.

Communicating Objects

A term created in the fall of 1992 by Mitel's VP Tony Bawcutt for a new Mitel division which specializes in making PC printed cards and software drivers and developer tools for those cards. Those cards are designed to be the building blocks of what Mitel calls multimedia applications ” but what are more properly called PC-based voice and call processing telecom developer building blocks. One of the first cards Mitel introduced was an ISDN S-access card which converts PCs into ISDN telephones, also called voice and data workstations.

Communicating Word Processor

A dedicated word processor that includes software for sending word processed files over phone lines. Communicating word processors have now largely been replaced by PCs (Personal Computers) running word processing programs and asynchronous communications software programs.

Communication Channel

A two-way path for transmitting voice and/or data signals. See also Circuit.

Communication Controller

Another name for a Front End Processor, a specialized computer which was common in 3270 data communications networks. The FEP acted as a data communications "traffic cop," removing the communications traffic routing and controlling burden from the mainframe computer which lay behind the FEP. In short, the FEP designates a device placed between the network and an input/output channel of a processing system (i.e. the computer).

Communication Endpoint

An ATM term. An object associated with a set of attributes which are specified at the communication creation time.

Communication Holder

A fancy name for a pocket on a piece of clothing that holds a cell phone. I first saw the word on a Nike Sno tech Jacket. The jacket also contains a small channel through which you can thread the wires to a compact headset you can wear. This way you can speak on the phone without touching the phone.

Communication Server

A dedicated, standalone system that manages communications activities for other computers.

Communication Workers Of America

CWA. A national union of telephone industry employees , currently very worried about its future membership growth given the phone industry's propensity to let its surplus workers go.

Communications Act Of 1934

Federal legislation which established national telecommunications goals and created the Federal Communications Commission to regulate all interstate and international communications.

Communications Act of 1996

It is really called the Telecommunications Act of 1996. It is a federal bill signed into law on February 8, 1996 "to promote competition and reduce regulation in order to secure lower prices and higher quality services for American telecommunications consumers and encourage rapid deployment of new telecommunications technologies." The Act, amongst other things, allowed the local regional Bell operating phone companies into long distance once they had met certain conditions about allowing competition in their local monopoly areas. You can download a copy of this Act (all 391,861 bytes) from See also CLEC, the Communications Decency Act of 1996 and the Telecommunications Act of 1996.

Communications Assistance to Law Enforcement Act

CALEA. A law passed in 1994, CALEA grants law enforcement agencies the authority to wiretap digital networks and requires wireless and wireline carriers to enable eavesdropping equipment to be used in digital networks.

Communications Decency Act of 1996

CDA. An element of the Telecommunications Act of 1996, the CDA provided for penalties of as much as $250,000 and 2 years in jail for U.S. citizens who transmit indecent material that minors could access by computer. Targeted at those who would make such material available over the Internet through Web sites, this element of the act was blocked in June 1996 by a panel of federal judges on the basis of successful arguments that the provision violated the right of free speech, as guaranteed in the Constitution. The Supreme Court in mid-1997 said the Communications Decency Act was unconstitutional. The Supreme Court handed down a seven-to-two decision that upheld a lower-court ruling against the CDA. The case, Reno vs. ACLU, was the first time that the Supreme Court has dealt with issues involving the Internet. See Telecommunications Act of 1996.

Communications Adapter

Device attached to an IBM System 3X computer or an IBM PC that allows communications over RS-232 lines.

Communications Control Character

A character intended to control or help transmission over data networks. There are ten control characters specified in ASCII which form the basis for character-oriented communications control procedures.

Communications/Modem Server

In a network, a server equipped with a bank of modems, which can be shared by users for outgoing calls.

Communications Parameters

Any of several settings required to allow computers to communicate successfully. In asynchronous transmissions, commonly used in modem communications, the settings for baud rate, number of data bits, number of stop bits, and parity parameters must all be correct.

Communications Protocol

Procedures which are employed to ensure the orderly transfer of data between devices on a communications link, over a communications network, or within a system. The major functions of a protocol are those of Handshaking and Line Discipline. Handshaking is a specific sequence of data exchange between devices over a circuit. This initial step establishes the fact that the circuit is operational, establishes the level of device compatibility, determines speed of transmission, and so on. Line discipline is a sequence of operations which includes transmission and receipt of data, error control, and sequencing of message sets (e.g., characters, blocks, packets, frames and cells). Line discipline also includes error detection and correction processes, providing for the confirmation or validation of data received, and by implication , the failure to receive data sets.

Communications Satellite

A satellite circling the earth, usually at a distance of about 22,000 miles, with electronic equipment for relaying signals received from the earth back to other points on the earth. See Geostationary Satellite.

Communications Server

A communications server is a machine with intelligence that does communications tasks. Exactly which tasks it does depends on your idea of what a communications server is. It's a loose term. Here are three definitions of what people do call a communications server:

  1. Its earliest configuration was a device that handled communications from several PCs and allowed those PCs access to printers, modems, etc.

  2. A communications server is also a type of gateway that translates the packetized signals of a LAN to asynchronous signals, usually used on telephone lines or on direct connections to minicomputers and mainframes. It handles different asynchronous protocols and allows nodes on a LAN to share modems or host connections. Usually one machine on a LAN will act as a gateway, sharing its serial ports or an RS-232 connection to a minicomputer. All devices on the LAN can use this machine to get to the modems and the minicomputer.

  3. A communications server is also the new name for an UnPBX. See UnPBX.

Communications Settings

Settings that specify how information is transferred from your computer to a device (usually a printer or modem).

Communications System Engineering

The translation of user requirements for the exchange of information into cost-effective technical solutions of equipment and subsystems.

Communications Toolbox

An extension of the Apple Macintosh operating system that provides protocol conversion and the drivers needed for communications tasks.

Communications Trouble and Analysis Center

CTAC. A Verizon center that provides a single point of contact for wholesale customers. The CTAC is the administrative center for monitoring and dispatching trouble calls, and for resolving usage, billing and connectivity issues.

Communications Workers of America

CWA. The main labor union of the RBOCs.

Communications Zone

A military term: Rear part of theater of operations (behind but contiguous to the combat zone), which contains the lines of communications, establishments for supply and evacuation, and other agencies required for the immediate support and maintenance of the field forces.


A British term. An alternative, and probably more meaningful, name for a telebusiness agent. A communicator is called a telemarketer in North America.


For the purposes of the FCC's cable television rules, when this term is used to specify the location of a transmitter or an antenna structure, it generally includes any named, urbanized area, without regard to size.

Community Antenna Television

CATV. Signals from distant TV stations are picked up by a large antenna, typically located on a hill, then amplified and piped all over the community below on coaxial cable. That's the original definition. See CATV for a more up-to-date definition.

Community Dial Office

CDO. A type of central telephone switching office that is most often found in small rural communities. It is an unattended switching center that is serviced only as needed, and maintained on an occasional basis by a traveling maintenance technician.

Community Name

Community Name is a password shared by a Network Agent and the Network Management Station so their communications cannot be easily intercepted by an unauthorized workstation or device.

Community Of Interest

A grouping of telephone users that call each other with a high degree of frequency. Often several Communities of Interest exist within an organization. This phenomenon can influence design for service when new switches are planned.

Community of License

The community to which a broadcast station is licensed, as specified on the station license. The transmitter may or may not be located within the community (indeed, it is frequently located at some distance, and may even be in a different state). A broadcast station is required to provide a specified field intensity over the entire Community of License.

Community String

A password used with the SNMP protocol, SNMP community strings are used for both read only and read/write privileges. A community string is case sensitive, and may include some punctuation characters.

Community Unit

A discrete geographic area served by a single cable television system, to which a single Community Unit Identification Number has been assigned by the FCC. At a minimum, each franchise area served by one cable operator constitutes one Community Unit; however, a single franchise area may include two or more Community Units in the following situations:

  • If a cable television operator serves a community from two different headends, the portion of the community served by each headend constitutes a separate community unit.

  • If two cable operators hold separate franchises for the same geographic area, each operator is assigned a separate Community Unit Identification Number.

  • If the system serves discrete, unincorporated areas within a township or county pursuant to a township-wide or county-wide franchise, each area may constitute a separate Community Unit.

  • If the system serves an incorporated municipality which overlaps two or more counties, the portion of the municipality within each county is considered a separate Community Unit.

Community Unit Identification Number

An identification number assigned by the FCC to each Community Unit. The format of the number is: SSNNNN, where:

  • SS is the U.S. Postal Service two-letter abbreviation for the state or territory in which the Community Unit is located.

  • NNNN = A four-digit serial number assigned by the FCC.


A device used on a dynamo to reverse the connection periodically in order to cause the current flow in one direction, i.e., to produce direct current.

Compact Disc

A standard medium for storage of digital audio data, accessible with a laser-based reader. CDs are 12 centimeters (about 4 3/4") in diameter. CDs are faster and more accurate than magnetic tape for audio. Faster, because even though data is generally written on a CD contiguously within each track, the tracks themselves are directly accessible. This means the tracks can be accessed and played back in any order. More accurate, because data is recorded directly into binary code; mag tape requires data to be translated into analog form. Also, extraneous noise (tape hiss) associated with mag tape is absent from CDs. See CD-ROM and CVD.

Compact Disc Interactive

A compact disc format, developed by Philips and Sony, which provides audio, digital data, still graphics and limited motion video. See CD-I.

Compact Wireless Markup Language



CompactPCI is a ruggedized variation of the PCI bus, which a bunch of industrial grade PC makers have designed for two reasons: First, to be able to put more PCI cards into one PC (8 versus 4). Second, to make the resulting PC more rugged, i.e. better able to withstand shaking, etc. The physical configuration of the hardware conforms to the Eurocard (VMR-style) standard. The cards, are identical to VME cards in size. They differ , however, in that they use a high density 2mm (contact spacing) pin-and-socket connector for interface to a passive backplane. CompactPCI typically comes in a rugged 3U or 6U Eurocard form factor and has a 32/64 data bus with transfer rates up to 528 megabytes per second. The PC makers told me that "CompactPCI is an adaptation of the Peripheral Component Interconnect (PCI) Specification for industrial and/or embedded applications requiring a more robust mechanism form factor than desktop PCI. CompactPCI uses industry standard mechanical components and high-performance connector technologies to provide a system optimized for rugged applications. CompactPCI is electrically compatible with the PCI Specification, allowing low-cost PCI chipsets to be used in a mechanical form factor suited for rugged environments."


See Companding.


The word is a contraction of the words "compressing" and "expanding." Companding is the process of compressing the amplitude range of a signal for economical transmission and then expanding it back to its original form at the receiving end.

Companion Virus

A virus which "infects" EXE files by creating a COM file with the same name and contains the virus code. They exploit the MS-DOS property that if two programs with the same name exist, the operating system will execute a COM file in preference to an EXE file.

Company Code

A unique four-place alphanumeric code which must be assigned by NECA (National Exchange Carrier Association) to all U.S. domestic local exchange telecommunications providers. The alphanumeric code is expressed as NNXX, where N=0-9 and X=A-Z. Company Codes are assigned for each type of service provided by a company. Additionally, separate and distinct codes are required for ILECs (Incumbent Local Exchange Carriers), certified facilities-based CLECs (Competitive LECs), local exchange resellers , and wireless carriers. In 1996, NECA assumed this responsibility. Previously, the codes were assigned unofficially from a series of numbers, sensitive to either the type of service provided or the nature of the carrier entity. See also NECA.


A military/government term: A method employed to segregate information of different desired accessibilities from each other. It may be used for communications security purposes.


A widely misused and especially vague word, "compatible" has several meanings. Hardware or software systems or components that are capable of working together in harmony (i.e., interoperating smoothly) can be characterized as compatible. The same goes for a product that is deemed by someone (usually a marketing type or a salesperson) to be equivalent to a better known product, as in "IBM-compatible." That means that that product can be used interchangeably. Hardware or software systems or components that fulfill the basic specifications defined in a formal standard are said to be compatible with that standard. In the computer world, two computers are said to be compatible when they will produce the identical result if they run identical programs. Being "compatible" doesn't always assure that the compatible thing will work. Check. See also Compliant, Compatible Sideband Transmission, Conformance Test and Interoperability Testing.

Compatibility Database

A compatibility database is a list of equipment and software that works with whatever the compatibility database is attached to. For example, Windows XP comes with a compatibility database. It tells you if the software application you're trying to install and run on Windows XP has been certified by Microsoft to work with XP. Try to install something not on the list and you get a warning.

Compatible Sideband Transmission

That method of independent sideband transmission wherein the carrier is deliberately reinserted at a lower level after its normal suppression to permit reception by conventional AM receivers. The normal method of transmitting compatible SSB (AME) is the emission of the carrier plus the upper sideband.

Compelled Signaling

A signaling method in which the transmission of each signal in the forward direction is inhibited until an acknowledgement of the satisfactory receipt of the previous signal has been sent back from the receiver terminal.


A favorite Microsoft word to describe what it regards as irresistibly great features of a new piece of software it has just created. You typically hear the word from Microsoft presenters at trade shows or seminars .

Competitive Access Provider

See CAP.

Competitive Local Exchange Carrier


Competitive Long Distance Coalition

A Washington, D.C. lobbying group.


The translation of programs written in a language understandable to programmers into instructions understandable to the computer. Think of programmers writing in every language but Greek and computers understanding only Greek. In this case, Greek is called machine language. The other languages (the programmer languages) are called things like COBOL, FORTRAN, Pascal, dBASE. A compiler is a special program that translates from all these other languages into machine language.


To translate a program written in a higher language into machine language so it can be executed by a computer.


A program that takes the source code a programmer has written and translates it into object code the computer can understand. For example, a compiler takes instructions written in a "higher" level language such as BASIC, COBOL or ALGOL and converts them into machine language that can be read and acted upon by a computer. The translated code is in the form of an executable program, which can be run on the target computer without additional translation software. Just-in-time compilers run on the client (i.e., target) machine, translating the code "on the fly." Optimizing compilers used in contemporary high-performance computers also ensure that the translations manage memory (i.e., caching and parallelization ) utilization as effectively as possible. Compilers convert large sections of code at one time, while interpreters translate commands one line at a time. See also Bytecode and Interpreter.


to fill up or complete. Do not confuse it with compliment, which means too be nice to someone, as in I compliment you on a job well done.

Complementary Code Keying

CCK. Modulation technique used by IEE 802.11 compliant wireless LANs for transmission at 5.5 and 11 Mbps. See CCK for a full explanation.

Complementary Metal Oxide Semiconductor


Complementary Network Service

CNS. CNSs are basic services associated with end user's lines that make it easier for ESPs to offer them enhanced services. Some examples of CNSs include Call Forwarding Busy/Don't Answer, Three Way Calling, and Virtual Dial Tone. See Open Network Architecture.

Complete Document Recognition

The ability to perform recognition on documents, retaining as much information as possible about the features and formatting of the original, and including the ability to capture images as well as text.

Completed Call

Careful with this one. In telephone dialect , a completed call is one that has been switched to its destination and conversation has begun but has not yet ended.

Completion Ratio

The proportion of the number of attempted calls to the number of completed calls.

Complex Programmable Logic Device



The term "compliant" is used to refer to a software or hardware component or system that fully conforms, or adheres, to a standard. Compliance is a higher level of conformance than is compatibility. See also Compatible and Conformance Test.


To be nice to someone, as in I compliment you on a job well done. Do not confuse it with complement, which to fill up or complete.

Complimentary Network Services

CNS. The means for an enhanced- service provider's customer to connect to the network and to the enhanced service provider. Complimentary network services usually consist of the customer's local service (e.g.,business or residence line) and several associated service options, e.g., call-forwarding service.


An element of equipment which unto itself does not form a system. Components can be semiconductors, resistors, capacitors, etc.


The science of analyzing and classifying the various elements of equipment. See Component.

Component Busy Hour

CBH. A telephone company definition. The busy hour of an individual component of a switching system. Often, component busy hours coincide with the overall office busy hour. Each component or group will have its own time consistent busy hour during the busy season. While the hour may or may not vary from one busy season year to another, only one hour may be used during a busy season year. It is upon the data collected during this component busy hour that trends are established, projections made, capacities set and future requirements derived. The component busy hour is used to determine the high day (HDCBH), ten highest days (10HDCBH), average of the ten highest days (ATHD), average busy day (ABD) and average busy season (ABS) CBH values.

Component Busy Season

The busy season during which the highest levels of traffic generally occur for which components of network facilities should be engineered.

Component Execution Environment

The runtime technical infrastructure, services, and facilities required to provide the appropriate separation layer for distributed components and to enable business components to collaborate. The reason this is done is to hide low-level technical issues from the functional developer.

Component Object Model

COM is Microsoft's cornerstone of its ActiveX platform. COM is a language independent component architecture (not a programming language). It is meant to be a general purpose, object-oriented means to encapsulate commonly used functions and services. The COM architecture provides a platform independent and distributed platform for multi-threaded applications. COM also encompasses everything previously known as OLE Automation (Object Linking and Embedding). OLE Automation was originally for letting higher level programming languages access COM objects. An object is a set of functions collected into interfaces. Each object has data associated with it. The source of the data itself is called the data object. With COM, the transfer of the data itself is separated from the transfer protocol.

Component Software

Component software is software constructed from reusable components. It was popularized by Microsoft Visual Basic and its successful custom control architecture. This architecture allows third party software components to "plug" into and extend the Visual Basic development environment. Hundreds of third party components, or custom controls, exist ” for everything from accessing a mainframe database to programming a computer telephony board. Component-based software development is a productive way to build software. System developers benefit from being able to tailor their development environment for a specific need. Consider the development of an IVR system that allows callers to access their account balance stored on an IBM mainframe. To build this system, Visual Basic developers extend their development environment with a custom control for telephony and another that provides access to an IBM mainframe. There's no need to learn a new and proprietary language for telephony development. Plus, every control is accessed through a common interface of actions, properties, and events.

Component Video

Transmission and recording of color television that stores separate channels of red, green and blue.


  1. Output of a multiplexer that includes all data from the multiplexed channels. Contrast with Aggregate.

  2. Refers to a type of color monitor in which the color signals all come in on the same line and are separated electronically inside the monitor. Compare this type of monitor to RGB, where the colors come in on different cables.

Composite Clock

A bipolar timing signal containing 64 khz bit-clock and 8 khz byte-clock frequencies

Composite Link

The datastream composed of all the input channels and control and signaling information in a multiplexed circuit. The Composite Link Speed is the transmission speed of the circuit.

Composite Materials

Composite materials consist of two or more components. They make it possible to combine the best properties of different materials; for example, the compression strength and low price of concrete with the tensile strength of reinforcing rods. Composite materials include: Reinforced concrete, fiber-reinforced plastic, fiber-rein- forced metals, plywood, chipboard and ceramics. The composites mainly considered for antennas are fiber-reinforced plastics. They combine the low weight and protective properties of plastics with the stiffness and strength of fiber.

Newton[ap]s Telecom Dictionary
Newton[ap]s Telecom Dictionary
ISBN: 979387345
Year: 2004
Pages: 133 © 2008-2017.
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