Audible Ring-Azimuth Beam Width

Audible Ring

A sound sent from the called party's switch to inform the calling party that the called line is being rung. A long explanation for a bell or buzzer that tells you it's for you.

Audible Ringing Tone

The information tone sent back to the calling telephone subscriber as an indication that the called line is being rung.

Audible Sound

Audible sound spans a huge range of frequencies from around 20 hertz (vibrations per second) to 20 kilohertz. See Sound.

Audible Tones

Audible tones are the sounds provided by the network or an attached switch to inform callers of the status of the line or of an event. Audible tones most frequently encountered in computer telephony applications include: ringing, busy tones (called party busy and network busy), SIT tones (Special Information Tones), and special tones used by computer telephony systems such as the "record at the beep" (which is usually a 1,000 Hz tone).


Sound you hear which may be converted to electrical signals for transmission. A human being who hasn't had his ears blown by listening to a Sony Walkman or a ghetto blaster can hear sounds from about 20 to 20,000 hertz.

Audio Bridge

In telecommunications, a device that mixes multiple audio inputs and feeds back composite audio to each station, minus that station's input. Also known as a mix-minus audio system.

Audio Crosspoint Module

Circuit board containing crosspoints for audio signal switching.

Audio Frequencies

Those frequencies which the human ear can detect (usually in the range of 20 to 20,000 hertz). Only those from 300 to 3,000 hertz are transmitted through the phone, which is why the phone doesn't sound "Hi-fi."

Audio Frequency

The band of frequencies (approximately 20 hertz to 20,000 hertz) that can be heard by the healthy human ear.

Audio Indexing Software

Audio indexing software creates a searchable index of speech content in digitized audio and video files. It allows for quick searches and rapid access to audio content.

Audio Interchange File Format

AIFF. A sound file format common to the Macintosh platform used to store digital audio data. This file format also supports position and loop point markers used by audio recording/editing software. Can be compressed into the AIFF-C format.

Audio Menu

Options spoken by a voice processing system. The user can choose what he wants done by simply choosing a menu option by hitting a touchtone on his phone or speaking a word or two. Computer or voice processing software can be organized in two basic ways ” menu-driven and non-menu driven. Menu-driven programs are easier for users to use, but they can only present as many options as can be reasonably spoken in a few seconds. Audio menus are typically played to callers in automated attendant/voice messaging, voice response and transaction processing applications. See also Menu and Prompts.

Audio Messaging Interchange Specification

AMIS. Issued in February 1990, AMIS is a series of standards aimed at addressing the problem of how voice messaging systems produced by different vendors can network or inter-network. Before AMIS, systems from different vendors could not exchange voice messages. AMIS deals only with the interaction between two systems for the purpose of exchanging voice messages. It does not describe the user interface to a voice messaging system, specify how to implement AMIS in a particular systems or limit the features a vendor may implement. AMIS is really two specifications. One, called AMIS-Digital, is based on completely digital interaction between two voice messaging systems. All the control information and the voice message itself, is conveyed between systems in digital form. By contrast, the AMIS-Analog specification calls for the use of DTMF tones to convey control information and transmission of the message itself is in analog form.

Audio Modulator

A device which combines audio with higher frequency radio signals for transmission.

Audio Oscillator

Hewlett-Packard's first product. They sold them at $54.40.

Audio Response Unit

A device which translates computer output into spoken voice. Let's say you dial a computer and it said "If you want the weather in Chicago, push 123," then it would give you the weather. But that weather would be "spoken" by an audio response unit. Here's a slightly more technical explanation: An audio response unit is a device that provides synthesized voice responses to dual-tone multi-frequency signaling input. These devices process calls based on the caller's input, information received from a host data base, and information carried with the incoming call (e.g., time of day). ARUs are used to increase the number of information calls handled and to provide consistent quality in information retrieval. See also Audiotex and Interactive Voice Response.

Audio Server

An audio server is a big PC which contains digitized music and software and sits on a network, local or distance. You use your browser to talk to your audio server. Its software responds. It allows you to choose which songs you want played and where ” in which rooms of your house, etc.

Audio Subcarrier

A Satellite Term . Carrier wave that transmits audio information.

Audio Text

The term used to describe a system that provides automated interactive telephone information, such as stock prices, sports scores and personals. Also spelled Audiotex and Audiotext.

Audio Track

The section of a videodisc or tape which contains the sound signal that accompanies the video signal. Systems with two separate audio tracks (most videodiscs) can offer either stereo sound or two independent soundtracks .


Another term for Teleconference. Teleconferences make use of conference bridges to allow participants to join a voice conference over the PSTN. See Teleconference.

Audiographic Conferencing

Teleconferencing that also allows participants to share and interact through graphics, figures and printed text. Hardware used during audio- graphic conferences includes facsimile , telewriters and film-based projectors. Transmission is via a narrowband telecommunications channel such as a telephone line or a radio sub- carrier.


The technology which allows sound and visual images to be transmitted simultaneously . According to AT&T, audiographics generally refers to single frame or slow frame visual images as opposed to continuous frame image transmission (e.g. television). Audiographic transmission is often used to teach or train people in remote locations from an educational institution or business training center, saving travel and housing expense.


A generic term for interactive voice response equipment and services. Audiotex is to voice what on-line data processing is to data terminals. The idea is you call a phone number. A machine answers, presenting you with several options, "Push 1 for information on Plays, Push 2 for information on movies, Push 3 for information on Museums." If you push 2, the machine may come back, "Push 1 for movies on the south side of town, Push 2 for movies on the north side of town, etc." See also Information Center Mailbox.


A different, and less preferred, spelling of Audiotex. See Audiotex.

Audio/visual Multimedia Services

AMS is an ATM term. It specifies service requirements and defines application requirements and application program interfaces (APIs) for broadcast video, videoconferencing, and multimedia traffic. AMS is being developed by the ATM Forum's Service Aspects and Applications (SAA) working group . An important debate in the SAA concerns how MPEG-2 applications will travel over ATM (asynchronous transfer mode). Early developers chose to carry MPEG-2 over ATM adaptation layer 1 (AAL 1); others found AAL 5 a more workable solution. Recently, some have suggested coming up with a new video-only AAL using the still- undefined AAL 2.

Auditory Pattern Recognition

Auditory pattern recognition is the ability to recognize spoken words.


To conduct an independent review and examination of system records and activities in order to test the adequacy and effectiveness of data security and data integrity procedures, to ensure compliance with established policy and operational procedures, and to recommend any necessary changes.

Audit File

On some systems, each time a billing file is generated, an audit file is created to record the details of the generation process.

Audit Trail

A record of all the events that occur when users request and use specific resources. An audit trail gives you the ability to trace who did what and who was responsible for what. An audit trail is a chronological record of system activities that is sufficient to enable the reconstruction, review, and examination of the sequence of environments and activities surrounding or leading to an operation, a procedure or an event in a transaction from its inception to final results. Audit trail may apply to information in an automated information system, to the routing of messages in a communications system, or to material exchange transactions, such as in financial audit trails. Audit trails are great for finding out what activity caused the disaster, the network to crash, etc. Audit trails are great for tracing crooks, i.e. unauthorized break-ins.


  1. Checking to see if the phone bill you got from your carrier is accurate. You do this by comparing it to your own telephone system's records.

  2. Tracking activities of users by record and selected types of events in the security log of a server or a workstation.


A type of drill bit typically used to make large, deep holes for passing wire or cable through wood.

Augmentation Of Bandwidth

Bandwidth augmentation is the ability to add another communications channel to an already existing communications channel.


Autonomous Unit Interface or Attachment Unit Interface. Most commonly used in reference to the 15 pin D type connector and cables used to connect single and multiple channel equipment to an Ethernet transceiver.

AUI Cable

Attachment Unit Interface Cable is usually a four-twisted pair cable that connects an Ethernet device to an Ethernet external receiver (XCVR).


Acceptable Use Policy. The term used to refer to the restrictions placed on use of a network; usually refers to restrictions on use for commercial purposes, most commonly with respect to the Internet.


Relating to the sense of hearing.


Access Usage Record.


AppleTalk Update-Based Routing Protocol. Method of encapsulating AppleTalk traffic in the header of a foreign protocol, allowing the connection of two or more discontiguous AppleTalk internetworks through a foreign network (such as TCP/IP) to form an AppleTalk WAN. This connection is called an AURP tunnel. In addition to its encapsulation function, AURP maintains routing tables for the entire AppleTalk WAN by exchanging routing information between exterior routers. See also AURP Tunnel.

AURP Tunnel

Connection created in an AURP WAN that functions as a single, virtual data link between AppleTalk internetworks physically separated by a foreign network (a TCP/IP network, for example). See also AURP.


ATM user service module.


Australian domestic satellite operator (now Optus).

Australian Radiocommunications Study Group

ARSG. An ITU study group which develops radiocommunications standards and regulatory procedures to allow for efficient and effective worldwide exploitation of the radiofrequency spectrum.

Australian Telecommunications Authority


Australian Telecommunication Standardisation Committee

The ATSC was formerly responsible for managing Australia's input to international and regional telecommunications technical standards. ATSC functions are now performed by the ACIF.


To establish, usually by challenge and response, that a transmission attempt is authorized and valid. To verify the identity of a user, device, or other entity in a computer system, or to verify the integrity of data that have been stored, transmitted, or otherwise exposed to possible unauthorized modification. A challenge given by voice or electrical means to attest to the authenticity of a message or transmission.

Authenticated SMTP

Authentication is means of verifying, or positively identifying, another party, like the sender of an e-mail message. E-mail makes use of SMTP (Simple Message Transfer Protocol), which is an application-layer extension of the TCP/IP (Transmission Control Protocol/Internet Protocol) protocol suite. TCP/IP and its various application-layer extensions form the fundamental protocols used in the Internet, which is an inherently insecure network of networks. One means of imposing a measure of security for e-mail is Authenticated SMTP, which blocks e-mail from other than trusted sources. That way you don't get a lot of spam. You also reduce the likelihood of contracting a computer virus, assuming that your trusted e-mail correspondents are as careful as you are about finding scanning for viruses and killing them. Encryption also is a good idea, as it secures your e- mails as they transverse the Internet. See also Authentication, Encryption, Internet, SMTP, TCP/IP, and Virus.


The process whereby a user or information source proves they are who they claim to be. In other words, the process of determining the identify of a user attempting to access a system. Authentication codes are exchanged between two computers that use SMTP. I believed that defining authentication was pretty simple until I came across the following definition in a book on cryptography. Here it is: Authentication is any technique enabling the receiver to automatically identify and reject messages that have been altered deliberately or by channel errors. Also, can be used to provide positive identification of the sender of a message although secret (symmetric) key algorithms may be used for some authentication without the prior sharing of any secrets between the messaging parties. See Authentication Token.

Authentication Center

See AuC.

Authentication Random Number

A random value used in authentication procedures.

Authentication Sequence Number

A sequence count that is incremented for each change of Authentication Random Number (ARN).

Authentication Token

A portable device used for authenticating a user. Authentication tokens operate by challenge/response, time-based code sequences, or other techniques. An example is Security Dynamics Technologies Inc.'s SecurID card. See Authentication.

Authority Zone

Associated with DNS, an authority zone is a section of the domain- name tree for which one name server is the authority. See also DNS.

Auto Available

An ACD feature whereby the ACD is programmed to automatically put agents into Available after they finish Talk Time and disconnect calls. If they need to go into After-Call Work, they have to manually put themselves there. See Auto Wrap-up.

Auto Changer

A jukebox-style optical media system that permits the storage and playback multiple discs. Autochangers are available for both 5-,8-, and 12-inch optical discs.

Auto Discovery

Process by which a network device automatically searches through a range of network addresses and discovers all known types of devices present in that range. Auto discovery is what takes place when a new device is added to a network. That device (e.g., an ethernet board, a modem, a router) communicates to the network management system that it is online and defines its key characteristics.

Auto Discovery is also the process by which MPOA (MultiProtocol Over ATM) edge devices automatically find each other through the ATM network. See MPOA.

Auto Fill-in

You're surfing the Web with your browser. You come to a form that needs being filled it. The form asks for your first name. You type H, as in Harry. A window pops up. It shows "Harry." Click on Harry. It will drop the word Harry into the line on the form that asks for your first name. Auto Fill-in is a time saving tool of new browsers. Some browsers actually do auto fill-in even more efficiently . They simply type "Harry" when they come to a form that says "first name?" Others require you to click.

Auto Greeting

ACD Agent's pre-recorded greeting that plays automatically when a call arrives.

Auto ID Center

A non-profit collaboration between private companies and academia that is pioneering the development of an Internet-like infrastructure for tracking goods globally through the use of RFID tags.

Auto Negotiation

Process that allows two devices at either end of a link segment to negotiate common features, speed and functions. It's a two-part process by which a network device automatically senses the speed and duplex capability of another device.

Auto Play

The Microsoft AutoPlay feature of the Windows operating system. This lets your CD run an installation program or the game itself immediately upon insertion of the CD-ROM.

Auto Responder

Auto responder is just what it sounds like. You send an email to an email address on the Internet. The person who owns the address is away. He has set up an "auto responder," which is a piece of software. That software automatically sends you a response. The most common use of auto responders is for vacation messages. "I'm away. I'll be back in the office on December 25 and will reply then. If you need help earlier, contact Joe Plumpudding on"

Auto Sensing

Process during which a network device automatically senses the speed of another device.

Auto Spid

When you install an ISDN device on an ISDN line you have to give that device the phone line's SPIDs ” Service Profile IDentifier numbers. The SPID is actually a label identifier that points to a particular location in your telephone company's central office memory where the relevant details of your ISDN service are stored. Auto SPID is an industry-wide initiative of ISDN equipment makers that automatically "negotiates" a connection to the telecom provider by downloading the SPID numbers from your digital central office switch. This means that in future, when you get an ISDN line, you won't have to worry about begging SPID numbers out of the telephone company.

Auto Wrap-up

An ACD feature whereby the ACD is programmed to automatically put agents into After-Call Work after they finish Talk Time and disconnect calls. When they have completed any After-Call Work required, they put themselves back into Available. See AutoAvailable.


A feature of a modem that allows it to answer incoming calls automatically.


Authoring is the process of using multimedia applications to create multimedia materials (including Web pages) for others to view. Multimedia authoring uses many tools, from the more familiar text editor or desktop publishing application, to tools for capturing and manipulating video images or editing audio files. Authors might include specialized creators of training, sales, or corporate applications such as insurance claims processing. Or, they might be creators of everyday business communications like voice- annotated email. Over time, everyone involved in business communications will probably have some level of multimedia authoring capability.

Authoring System

Software which helps developers design interactive course- ware easily, without heavy computer programming. A specialized, high-level, plain-English computer language which permits non-programmers to perform the programming function of courseware development. The program logic and program content are combined. See Authoring.


Think of charging things on your MasterCard, Visa, or American Express card. If the store cannot authorize the amount of your purchase, your Visa card will not allow you to make the purchase. Authorization is needed for many long distance calls, especially those made using credit cards, telephone company calling card, etc. Authorization is done by the operator's computer checking with the remote validation database service. See BVA, BVS and Validation.

Authorization Code

A code in numbers and/or letters employed by a user to gain access to a system or service. If you are making a call out on a restricted line, the PBX will ask you for an authorization code. If you have one, your call will go through. If not, your call will be denied (i.e. not go through). Authorization codes come in various flavors. Some can be used for making long distance calls. Some can be used also for international calls, etc. See Authorized User.

Authorized Agent

Also called Authorized Sales Agent. A term chosen by some of the Bell operating companies and many of the cellular phone companies to refer to companies which sell their network services on commission. Some of these companies have specific industry knowledge and have written specialized software. The idea is to work with businesses to arm them with the absolute best package of telecommunications hardware, software and services.

Authorized Bandwidth

The necessary bandwidth required for transmission and reception of intelligence. This definition does not include allowance for transmitter drift or Doppler shift.

Authorized Dealer

See Dealer.

Authorized Frequency

A frequency that is allocated and assigned by an authority to a specific user for a specific purpose.

Authorized User

A person, firm, corporation or any other legal entity authorized by the provider of the service to use the service being provided.

Auto Answer

The capability of a phone, a terminal, a video phone, a modem or a computer to answer an incoming call and to set up a connection without anyone actually doing anything to physically answer the call. I have auto answer on my video phone. When it rings, my phone answers and I see who's calling. It's nice.

Auto Attendant

A shortened name for an automated attendant, a device which answers a company's phones, encourages you to touchtone in the extension you want, and rings that extension. If that extension doesn't answer, it may send the call to voice mail or back to the attendant. It may also allow you to punch in digits and hear information, e.g. the company's hours of business, addresses of local branches, etc. See also Automated Attendant.

Auto Baud

Automatic speed recognition. The ability of a device to adapt to the data rate of a companion device at the other end of the link.

Auto Baud Detect

See Auto Baud.

Auto Busy Redial

A feature of a phone or phone system where the phone has the ability to keep trying a busy number until answered . The circuit actually recognizes the busy tone, hangs up, and dials again. One of the greatest time-savers ever invented.

Auto Call

Automatic Calling; a machine feature that allows a transmission control unit or a station to automatically initiate access to (i.e. dial) a remote system over a switched line.

Auto Dial

A feature of phone systems and modems which allows them to dial a long phone number (usually long distance) by punching fewer buttons than there are numbers to dial. One button auto dial on electronic phones is very common these days. Most communications software programs will allow you to auto dial a string of 35 to 40 digits, which you may need if you're dialing through a complex network.

Auto Dial Auto Answer

A modem feature. Auto Dial lets you dial a phone number through your modem, using your personal computer or data terminal keyboard. Auto Answer permits the modem to automatically answer the incoming call without anybody having to be there.

Auto Dialer

See Automatic Dialer.

Auto Fax Tone

Also called CNG, or Calling Tone. This tone is the sound produced by virtually all Group 3 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. See also CNG.

Auto Line Feed

An instruction in a communications program which causes the program to perform a Line Feed (LF) when you hit a carriage return or the "Enter" key.

Auto Partition

A feature of 10Base-T. When 32 consecutive collisions are sensed by a port in a hub or concentrator from its attached workstation or network segment, or when a packet that far exceeds the maximum allowable length is received, the port stops forwarding packets. The port continues to monitor traffic and will automatically begin normal packet forwarding when the first correct packet is received.

Auto Recognition

A term used in file conversion in which your conversion software figures out by itself in what form the original file was ” WordPerfect 5.0, Word 6.0, Wordstar 5.5 etc. See also Auto Styling.

Auto Reconfiguration

The process performed by nodes within the failure domain of a Token Ring network. Nodes automatically perform diagnostics in an attempt to reconfigure the network around failed areas. See also failure domain.

Auto Selection Tool

An imaging term. A tool that selects an entire area within a specified range of color values around a selected pixel.

Auto Sensing

See Auto Styling.

Auto Start

A standby electrical power system that starts up when the normal supply of commercial power fails.

Auto Stream

An AT&T ISDN term. The method of data flow in which both channels between the ISDN set and the application are in use simultaneously.

Auto Styling

Auto styling is a term we found in a database conversion software program. What it means is that the program looks at the data in a field and determines from that data if the field is a numeric, character or memo, etc. The problem with auto styling is that it's frequently wrong. For example, it might check one field, find all numbers and decide it's a numeric field. Such a field might be a zip code, which actually is normally a character field. One reason why you might want you zip code to be a character field is that character fields are set left. Numeric fields are set right. (They line up at the decimal point.) Another name for auto styling is auto sensing.


A feature of a telephone which automatically answers incoming calls without the user of the phone lifting a handset or otherwise answering the call. Modems and fax machines also autoanswer. In North America, it's spelled AUTO ANSWER. In Britain, it's spelled Autoanswer.


See Automated Attendant.


The process by which the terminal software determines the line speed on a dial-up line.


The worldwide data communications network of the U.S. Department of Defense. Acronym for "AUTOmatic DIgital Network."

Autodial Button

An Autodial button on a phone provides one-touch dialing of outside numbers, intercom numbers, or feature codes.

Automated Attendant

A device which answers callers with a digital recording, and allows callers to route themselves to an extension through touch tone input, in response to a voice prompt. An automated attendant avoids the intervention of a human being in the form of a console attendant, thereby avoiding related personnel costs. Commonly implemented in Voice Processor systems and software, front-ending PBXs and ACDs.

An automated attendant is typically connected to a PBX or a Centrex service. When a call comes in, this device answers it and says something like, "Thanks for calling the ABC Company. If you know the extension number you'd like, pushbutton that extension now and you'll be transferred. If you don't know your extension, pushbutton "0" (zero) and the live operator will come on. Or, wait a few seconds and the operator will come on anyway." Sometimes the automated attendant might give you other options such as "dial 3 for a directory of last names and dial 4 for a directory of first names ." Automated attendants are also connected to voice mail systems ("I'm not here. Leave a message for me."). Some people react well to automated attendants. Others don't. A good rule to remember is before you spring an automated attendant on your people/customers/subscribers, etc., let them know. Train them a little. Ease them into it. They'll probably react more favorably than if it comes as a complete surprise. The first impression is rarely forgotten, so try to make it a good experience for the caller. See also Dial By Name.

Automated Coin Toll Service

ACTS. In the old days, operators handled routine toll calls by counting the sound of coins hitting the box, checking prices, putting calls through, figuring and collecting overtime charges, etc. ACTS does all this automatically. It figures charges, tells those charges by digitized computerized voice to the customer, counts the coins as they are deposited and then sets up the call.

Automated Maritime Telecommunications System

An automatic, integrated and interconnected maritime communications system serving ship stations on specified inland and coastal waters of the United States.

Automated Meter Reading

See AMR.

Automated Radio

A radio with the capability for automatically controlled operation by electronic devices that requires little or no operator intervention.

Automated Tactical Command And Control System

A command and control system or part thereof which manipulates the movement of information from source to user without intervention. Automated execution of a decision without human intervention is not mandatory.

Automated Telephone Listing Address System

ATLAS. Central repository for Verizon Listings data. Input data is from Verizon Retail, Wholesale, and Independent tlephone companies. ATLAS users include Verizon Directory Assistance and Directory Publishing.

Automated Voice Response Systems

AVRS. Devices which automatically answer calls. They may simply inform the caller that the call is in a queue and will be answered soon; alternatively they can prompt the caller to use voice commands, or touch- tones to seek more information.


See Seamless.

Automatic Address Discovery

This refers to the process by which a network device can poll other network devices to discover the network addresses which each device supports. Automatic address discovery makes the set up and on-going maintenance of complex internetworks much simpler than if all address updates were performed manually.

Automatic Alternate Routing

AAR. A call going through a network can get a connection via secondary routes between two locations without need for the user's intervention, i.e. automatic.

Automatic Button Restoration

When the telephone handset of a multi- line instrument (typically a 1A2 multi-line key set) is placed back in its cradle, the line button being used automatically "pops" back up. Conversely, when a user picks up the hand- set, he must always push down a line button to make a call. Most phones with this feature can be disabled, so the buttons stay down when the handset sits on the cradle. A twist of a single screw inside the instrument will usually solve the aggravation of the automatic button restoration. Some people like automatic button restoration because it saves a user from accidentally barging into someone else's call. This was a much greater problem with 1A2 key systems. It no longer is a problem with most electronic key systems since they usually extend the user automatic privacy once they get on a call so no one else can barge in, even if they want to.

Automatic Call Distributor

ACD. A specialized phone system originally designed simply to route an office's incoming calls to all available personnel so that calls are evenly distributed. Now increasingly used by companies also making outgoing calls. You receive and make lots of phone calls typically to customers. You need an ACD. Once used only by airlines, rent-a-car companies, mail order companies, hotels, etc., it is now used by any company that has many incoming calls (e.g. order taking, dispatching of service technicians, taxis, railroads, help desks answering technical questions, etc.). There are very few large companies today that don't have at least one ACD. Many smaller companies, like the company that publishes this dictionary, also have one.

An ACD performs four functions.

  1. It will recognize and answer an incoming call.

  2. It will look in its database for instructions on what to do with that call.

  3. Based on these instructions, it will send the call to a recording that "somebody will be with you soon, please don't hang up!" or to a voice response unit (VRU).

  4. It will send the call to an agent as soon as that operator has completed his/her previous call, and/or the caller has heard the canned message.

The term Automatic Call Distributor comes from distributing the incoming calls in some logical pattern to a group of operators. That pattern might be Uniform (to distribute the work uniformly) or it may be Top-down (the same agents in the same order get the calls and are kept busy. The ones on the top are kept busier than the ones on the bottom). Or it may be Specialty Routing, where the calls are routed to answerers who are most likely to be able to help the caller the most. Distributing calls logically is the function most people associate with an ACD, though it's not the most important.

The management information which the ACD produces is much more valuable . This information is of three sorts:

  1. The arrival of incoming calls (when, how many, which lines, from where, etc.)

  2. How many callers were put on hold, asked to wait and didn't. This is called information on ABANDONED CALLS. This information is very important for staffing, buying lines from the phone company, figuring what level of service to provide to the customer and what different levels of service (how long for people to answer the phone) might cost. And

  3. Information on the origination of the call. That information will typically include ANI (Automatic Number Identification ” picking up the calling number and DNIS (Direct Number Identification Service) picking up the called number. Knowing the ANI allows the ACD and its associated computer to look up the caller's record and thus offer the caller much faster service. Knowing the DNIS may allow the ACD to route the caller to a particular agent or keep track of the success of various advertising campaigns . Ad agencies will routinely run the same ad in different towns using different 800 phone numbers. Picking up which number was called identifies which TV station the ad ran on.

The seven definitions that follow the definition "ACD" show some of the features which newer ACDs have. See also 800 Service, ACD and Automatic Call Sequencer.

Automatic Call Intercept

A feature of a Rolm ACD. This feature automatically forwards calls to an attendant if the dialed number is not installed or out of order. It can also intercept an attempted trunk call that is in violation of a Class of Service restriction. Automatic Call Intercept will also recall the attendant after a predetermined period of off- shoot inactivity (e.g. flash or hold).

Automatic Call Reconnect

Feature permitting automatic call rerouting away from a failed trunk line.

Automatic Call Rescheduling

When a call is unsuccessful , due to no reply or busy signal, the system will automatically dial the number again after a pre-determined time.

Automatic Call Sequencer

A device for handling incoming calls. Typically it performs three functions.

  1. It answers an incoming call, gives the caller a message, and puts them on "Hold."

  2. It signals the agent (the person who will answer the call) which call on which line to answer. Typically, the call which it signals to be answered is the call which has been on "hold" the longest.

  3. It provides management information, such as how many abandoned calls there were, how long the longest person was kept on hold, how long the average "on hold" was, etc.

There are three types of devices which handle incoming calls. The least expensive is the Automatic Call Sequencer which is traditionally used with key systems. It differs from Uniform Call Distributors (UCDs) and Automatic Call Distributors (ACDs) in that it has no internal switching mechanism and does not affect the call in any way. It simply recommends which call should be picked up and keeps statistical information on the progress of calls. A more expensive type of device is the UCD.

The most full-featured and expensive is the ACD. Distinctions between ACDs and UCDs and/or PBXs with features called UCDs and ACDs are blurring as UCDs get more sophisticated. The main difference, as we understand it, is that a UCD offers fewer options for routing an incoming call and answering calls in any particular order. ACDs typically produce the most detailed management information reports . One company also makes something called an Electronic Call Distributor. It is essentially an automatic call distributor.

Automatic Callback

When a caller dials another internal extension and finds it busy, the caller dials some digits on his phone or presses a special "automatic callback" button. When the person he's calling hangs up, the phone system rings his number and the number of the original caller and the phone system automatically connects the two together. This feature saves a lot of time by automatically retrying the call until the extension is free. See also CAMP ON. Wouldn't it be nice if they had this feature on long distance calls? *66 is the usual code to access Automatic Callback.

Automatic Calling Unit

ACU. A device that places a telephone call on behalf of a computer.

Automatic Circuit Assurance

ACA is a PBX feature that helps you find bad trunks. The PBX keeps records of calls of very short and very long duration. If these calls exceed a certain parameter, the attendant is notified. The logic is that a lot of very short calls or one very long call may suggest that a trunk is hung, broken or out of order. The attendant can then physically dial into that trunk and check it.

Automatic Controls

Controls that are automatically started by switching systems in response to a threshold value being exceeded.

Automatic Cover Letter

In a fax transmission, an automatic cover letter allows the user to automatically attach a cover letter to the document being sent. This is especially convenient when sending material directly from your PC.

Automatic Data Speed Recognition

ADSR. A function of integrated voice/data PBXs to permit data devices and terminals of various data speeds to be connected within the PBX. ADSR is frequently associated with an "automatic modem select" function in "modem pooling" arrangements or with "format and protocol conversion" capability to provide internal data calls between dissimilar devices and terminals. PBXs don't switch data calls much these days. Local area networks now do that. See Local Area Network.

Automatic Dialer Or Autodialer

A device which allows the user to dial pre-programmed telephone numbers by pushing one or two buttons. Sometimes referred to as a " repertory " dialer. Dialers can be bought as a separate device and added to a phone. Today most telephone sets are outfitted with autodialers. There are four basic measures of an automatic dialer's efficiency.

  1. What's the longest number it will dial automatically? This is important because using some of AT&T's long distance competitors requires dialing lots of numbers, with lots of pauses.

  2. How many numbers will it dial? Some people like to have a dialer which dials hundreds of numbers. Others like a small one, just for their most frequently called numbers.

  3. Will the dialer recognize dial tone? This is important because using a long distance company or dialing through a PBX requires one to recognize consecutive dial tones.

  4. Can you "chain" dial? In other words, can you hit one speed dial button after another and have the machine dial through a complex network and throw in authorization codes, etc.?

Automatic Dialing

See Speed Dialing.

Automatic Directory Propagation

In electronic mail, automatic directory propagation is the ability to update addresses automatically in one domain after manually entering address changes in another domain, whether on the same LAN or another LAN connected by a gateway. In general, automatic directory propagation can be peer-to-peer, where changes in any post office are sent to all other post offices, or master-to-slave, where changes in the master post office are sent to the slaves, but changes in the slave post office do not go to the master.

Automatic Equalization

The process of compensating for distortion of data communications signals over an analog circuit.

Automatic Exchange

A term for a central office which automatically and electronically switches calls between subscribers without using an operator. Not a common term.

Automatic Exclusion

A telephone system function in which the first station on a line prevents access by all others on that line; identified with "bridge lifters" in local wire telephone plant; can be duplicated in digital local exchanges with software. See Automatic Privacy.

Automatic Facilities Test System

AFACTS is a Rolm CBX feature. It is an automatic testing system for identifying faulty tie and central office trunks. AFACTS can pinpoint faulty trunks and generate exception and summary reports.

Automatic Fallback

A modem's ability to negotiate an appropriate data rate with the modem on the other end of the link, depending on line quality. For example, if two 2400 baud modems can not pass data at 2400 baud, they would "fall back" to 1200 baud automatically in order to transmit data without excessive errors.

Automatic Forwarding

A feature of many e-mail programs that automatically retransmits incoming messages to another e-mail address.

Automatic Frequency Control

A circuit in a radio receiver which automatically brings the tuning units of the set into resonance with a wave which is partially tuned in.

Automatic Gain

This is an electronic circuit which automatically increases the volume when someone is speaking quietly and drops it when someone is speaking loudly. The idea is to keep the transmitted signal even. Most tape recorders , for example, have automatic gain circuits. This allows them to pick up voices of people in a room, even though the volume of each person's conversation arriving at the tape recorder is different. The problem with automatic gain circuits is they're always looking for something to amplify. Thus, when it is quiet (and meant to be), the automatic gain circuit will try to amplify the ambient noise in the room ” to keep the sound level constant. All professionally recorded tapes are done on tape recorders with manual volume controls.

Automatic Hold ” Station or Intercom

When a user is having a conversation and receives another call, he may press the button to answer that new call. The call he was on originally is automatically put on hold.

Automatic Identification

Sometimes called automatic data capture. These are methods of collecting data and entering it directly into computer systems without human involvement. Technologies normally considered part of auto-id include bar codes, biometrics, RFID and voice recognition.

Automatic Identified Outward Dialing

AIOD. The toll calls placed by all extensions on the telephone systems are automatically recorded. This information allows bills to be sent, long distance lines to be chosen, etc. Some central offices, for example, can provide an itemized breakdown of charges (including individual charges for toll calls) for calls made by each CPE telephone extension. See Call Accounting, Call Detail Recording, SMDR and AIOD.

Automatic Intercept Center

AIC. A Bellcore definition: "The centrally located set of equipment that is part of an Automatic Intercept System (AIS) that automatically advises the calling customer, by means of their recorded or electronically assembled announcements, of the prevailing situation that prevents completion of connection to the called number."

Automatic Intercept System

A type of switching system for handling intercept calls, typically used by phone companies and typically totally automated these days. When calling a number, an automatic intercept system might come on and say, "I'm sorry the number you just dialed has been changed, If you'd like to connect to the new one, please hit your star button. You will be charged 75 cents for the privilege."

Automatic Level Control

ALC. A control system that adjusts the incoming signal to a predetermined level. Somewhat similar to automatic gain control. See Automatic Gain Control.

Automatic Light Control

ALC. Vidicon camera control which automatically adjusts the target voltage to compensate for variations in light levels. See also Automatic Gain.

Automatic Line Hold

A PBX feature. As long as a phone does not go "on-hook," activation of various line pushbuttons will automatically place the first line on hold without the use of a special "hold" button.

Automatic Location Identification

ALI. Working with Automatic Number Identification, the use of a database to associate a physical location with a telephone number.

Automatic Line Insulation Testing

ALIT. Equipment located in a Central Office which sequentially tests lines in the office for battery crosses and grounds.

Automatic Link Establishment

ALE. The capability of an HF radio station to contact, or initiate a circuit, between itself and another specified radio station, without operator assistance and usually under computer control. ALE techniques include automatic signaling, selective calling, and automatic handshaking. Other automatic techniques that are related to ALE are channel scanning and selection, Link Quality Analysis (LQA), polling, sounding, message store and forward, address protection, and anti-spoofing .

Automatic Message Accounting

The network functionality that measures, collects, formats, and outputs subscriber network-usage data to upstream billing OSs and other OSs (Operations Systems).

Automatic Message Switching

A technique of sending messages to their appropriate destination through information contained in the message itself ” typically in its "address."

Automatic Network Restoral

Automatic network restoral is a term which reflects the ability of a network to restore service rapidly and automatically following a catastrophic failure, such as that of a network cable cut. The result is higher network availability and reliability.

Automatic Number Announcement Circuit


Automatic Number Identification

ANI. Being able to recognize the phone number of the person calling you. You must have equipment at your office. And the network must have the ability to send the calling number to you. For a much longer explanation, see ANI, CALLER ID, CLASS, ISDN and System Signaling 7.

Automatic Overflow To DDD

Toll calls jump to expensive direct distance dialed calls, when all lower cost FX, WATS lines, etc. are busy.

Automatic Phone Relocation

The Automatic Phone Relocation feature now available on some phone systems allows a telephone to retain its personal and system programming when it is reconnected to another physical location.

Automatic Privacy

When someone is speaking on a phone line or on an intercom, this feature ensures no one else can accidentally or deliberately butt into that conversation. If you did, however, want somebody else to come into the conversation (for example, someone to provide some additional information), there's usually another feature called Privacy Release. By pushing this button on the phone, other people who have the same extension button or intercom button on their phones can then push their buttons and join the conversation. Or you can bring them into your conversation by dialing them in. Most modern key systems come with Automatic Privacy. Many people don't like it, especially those who live in small offices. Some newer phone systems are coming standard without it. And you have to program it in, if you want it.

Automatic Program Load

APL is a PBX feature that allows it to load its own software into RAM from a local device such as a hard disk or a floppy disk. All this takes place automatically without human intervention. APL is an important feature since it often determines how fast a PBX can get back into service after some sort of failure ” usually a failure in commercial power.

Automatic Protection Switching

  1. APS. The ability of a network element to detect a failed working line and switch the service to a spare (protection) line. 1+1 APS pairs a protection line with each working line. 1:n APS provides one protection line for every n working lines.

  2. Switching architecture designed for SONET to perform error protection and network management from any point on the signal path .

Automatic Queuing

Queuing is exactly as it sounds. Something you want is being used. So you get placed in line for that device. There are two types of queuing ” automatic and manual. Manual is when you're put in queue by a person, for example an operator. Automatic is when you're put in queue by a machine, for example a PBX aided by its software.

Automatic Recall

  1. A central office feature which gives telephone subscribers the ability to automatically redial their last incoming call ” without actually knowing that number. On some central offices it is now possible for the calling person to block the ability of someone they've called to automatically call them back. The service is typically known as star sixty-nine ” i.e. *69.

  2. A PBX feature which returns a call to the PBX attendant (or alerts the attendant) if a call extended to a telephone is not answered within a pre-set period of time. The most logical time is three rings, or 18 seconds. This feature allows the attendant to give the caller some information, take a message or connect the caller to someone else. Most hotel switches have this feature. And when the call doesn't get answered, the switch sends it back to the operator. The sad thing is that the hotel operator is usually so busy, he/she keeps you waiting another 20 or 30 seconds, irritating you.

Automatic Recharge

You give your credit card to a long distance phone company. Instead of charging your card at the end of each month for your usage, they charge you upfront, say $25. When you've used up $20 of calls, they then charge you another $25. This is called automatic recharge. This method is also used by highways for collecting of tolls,for example EZPass in New York surrounding states.

Automatic Recovery

Your telephone system dies ” typically because its power is cut off. Once the power comes on, instructions in the machine direct it to reload its software so that within minutes the system can be back and running normally. Those "instructions" are normally not affected by power drops.

Automatic Redial

A telephone capable of detecting a busy signal and redialing the call until a connection is obtained. Often called "Demon Dialer" after a consumer unit made for telephones. See also Automatic Recall.

Automatic Replication

Also known as data replication. It refers to the process of automatically duplicating and updating data in multiple computers on a network. The word "automatically" in this case means that the process of duplication is handled without human intervention by the software responsible. The idea is that if one or several of the machines go down, the company using the data will still have reliable data.

Automatic Rerouting

This refers to the process by which an intelligent voice or data network can automatically route a call, or virtual circuit, around a network failure. With frame relay, PVCs represent a fixed path through the network. However, in the event of a network failure along the primary path over which the PVC is routed, the PVC will be automatically routed to a secondary network path until the primary path is physically restored.

Automatic Restart

  1. The process by which a mechanism automatically restarts after power fails. Restart is from the exact point of interruption.

  2. System facilities that allow restart from the point of departure after system failure.

Automatic Ring Down

ARD. A private line connecting a station instrument in one location to a station instrument in a distant location with automatic two-way signaling. The automatic two-way signaling used on these circuits causes the station instrument on one end of the circuit to ring when the station instrument on the other end goes off-hook. This circuit is sometimes called a "hot-line" because urgent communications are typically associated with this service. ARD circuits are commonly used in the financial industry. May also have one way signaling only.

Automatic Ringdown Tie Trunk

A direct path signaling facility to a distant phone. Signaling happens automatically when you lift the receiver on either phone. See also Manual Ringdown TIE Trunk.

Automatic Rollback

A feature of the Transaction Tracking System (TTS) that returns a database on a Novell NetWare local area network to its original state. When a network running under TTS fails during a transaction, the database is "rolled back" to its most recent complete state. This prevents the database from being corrupted by the incomplete transaction.

Automatic Route Optimization

  1. See Automatic Route Selection.

  2. In some switching systems, may denote added ability to adjust routing depending on traffic load or time of day.

Automatic Route Selection

Your phone system automatically chooses the least costly way of sending a long distance call. See Least Cost Routing and Alternate Routing.

Automatic Routing Management

Formerly AutoRoute. The connection- oriented mechanism used in Cisco WAN switches to provide connectivity across the network. Switches perform a connection admission control (CAC) function on all types of connections in the network. Distributed network intelligence enables the CAC function to route and reroute connections automatically over optimal paths while guaranteeing the required QoS.

Automatic Scheduled Testing

AST. A method of testing switched access service (Feature Groups B, C, and D) where the customer provides remote office test lines and 105 test lines with associated responders or their functions' equivalent; consists of monthly loss and C-message noise tests and annual balance test.

Automatic Secure Voice Communications Network

AUTOSEVOCOM. A worldwide, switched, secure voice network developed to fulfill Department of Defense (DoD) long-haul, secure voice needs.

Automatic Send/Receive

Automatic Send Receive, or ASR. A teletype or telex machine manufactured by the Teletype Corporation. See ASR for more detail.

Automatic Sequential Connection

A service feature provided by a data service to connect automatically, in a predetermined sequence, the terminals at each of a set of specified addresses to a single terminal at a specified address.

Automatic Set Relocation

A phone system feature which allows a telephone to retain its personal and system programming when it is reconnected to another physical location.

Automatic Slope Control

ASC. Circuitry that permits amplifier response compensation for varying slope, or tilt, at its input.

Automatic Spanning Tree

See AST.

Automatic Speech Recognition

ASR. See Speech Recognition.

Automatic Speed Matching

The ability of an asynchronous modem to automatically determine whether it is expected to communicate at 300, 1200 or 2400 bps.

Automatic Time-Out On Uncompleted Call

A PBX feature. If a phone stays "off-hook" without dialing for a predetermined time interval, or stays connected to a busy signal longer than the predetermined time interval, the intercom switching equipment will automatically connect this phone to intercept.

Automatic Toll Ticketing

A system which makes a record of the calling phone number, the called number, the time of day, the length of the call, etc. and then generates an instant phone bill for that call. Often used in hotel/motels.

Automatic Traffic Overload Protection

ATOP. A Rolm feature defined as a dynamic form of line-load control, which automatically denies a dial tone during those periods when the Rolm CBX may become overloaded. One wonders why someone would create this feature.

Automatic Trunk

A dial connection whose destination is predetermined, thus a request for service (called a seizure) initiates dialing to the programmed destination.

Automatic Vehicle Location

See AVL.

Automatic Voice Network

AUTOVON, the principal long-haul, unsecure (meaning it's not secure) voice communications network within the Defense Communications System. See AUTOVON.

Automatic Volume Control

A circuit in a radio receiver; automatically maintains various received transmissions at approximately the same volume.

Automatic Wakeup

The capability for the user to schedule a wakeup call to a predetermined telephone number, either one time or daily.

Automatic Wakeup Service

The guest or the operator dials into a machine which records a request for a guest wakeup call the following morning. The auto wakeup machine is a glorified , programmable auto-dial answering machine. The machine is said to save hotels money and make wakeup calls more reliable, and certainly more anonymous.

Automative Gain Control

AGC is used to protect a device from optical overload while maintaining bandwidth and sensitivity performance.


See Bot.


Of relating to, or controlled by the autonomic nervous system. Acting or occurring involuntarily; automatic; an autonomic reflex. See Autonomic Nervous System.

Autonomic Computing

A term coined by IBM to describe the concept of a self- managing computing system. Imagine a computer system that can look after itself in the same way that our autonomic nervous system does, without requiring any conscious effort on our part. The developing technology aims to allow computer systems to self-manage and heal themselves, automatically resolving the problems systems administrators face managing performance, reliability, security, consistency and scalability with hundreds of networked computers with complex tasks and huge data sets. According to Steve Wojtowecz, director of strategy for IBM Tivoli, there are five stages of evolution in autonomic computing:

  1. Basic - Systems administrators manually analyze and solve problems.

  2. Managed - There are centralized tools, but actions are still taken manually.

  3. Predictive - Administrators use automated tools as a cross resource and to make recommendations.

  4. Adaptive - An automated tool monitors systems, correlates and takes corrective action.

  5. Autonomic - the point at which administrators will simply need to set management rules for business policy and let the system take care of itself.

Autonomic Nervous System

That part of the nervous system that governs involuntary body functions like respiration and heart rate.

Autonomous Confederation

A group of autonomous systems that rely on their own network reachability and routing information more than they rely on that received from other autonomous systems or confederations.

Autonomous System Number

ASN. A unique number assigned by the InterNIC that identifies an autonomous system in the Internet. ASNs are used by routing protocols (like BGP ” Border Gateway Protocol) to uniquely define an autonomous system.


The process performed by nodes within the failure domain of a token ring network. Nodes automatically perform diagnostics in an attempt to reconfigure the network around the failed areas. See also Failure Domain.


An e-mail that is automatically sent in reply to any e-mail received in a specified mailbox. Also known as a vacation message.


A drawing feature that automatically adjusts the axis units of a graph to the minimum and maximum numerical values of a set of data.


See Recorder.


A United Kingdom definition. The process of selecting records from a database using pre-defined criteria and allocating the records to outbound or mailing campaigns.


The AUTOmatic SEcure VOice COMmunications system of the U.S. Department of Defense (DoD). A worldwide, switched, secure voice network developed to fulfill DoD long-haul, secure voice needs.



Autotimed Recall

When a user places a call on hold and forgets about it, Autotimed Recall will ring that user or the receptionist after a predetermined time. That time is usually programmable. It shouldn't be longer than 30 seconds; otherwise, your customers, sitting endlessly on your eternity hold, will go nuts and go elsewhere.

Autotimed Transfer

This telephone system feature switches unanswered incoming calls to a backup answering position after a predetermined (usually adjustable) interval of time.

Autotype Protocol

Hayes Microcomputer definition for a file transfer protocol which allows the user to automatically "type" a disk file, the clipboard or the contents of Smartcom Editor in either plain text (ASCII) or ANSI.SYS format to a remote computer. Pacing, send lines and await character echo options are provided. If necessary, character set mapping translates between different code pages and systems (Macintosh or Windows text files, for example).


AUTOmatic VOice Network. During the early years of the "Cold War," AUTOVON was built on the foundation of the U.S. Army's three-switch SCAN (Switch Communications Automatic Network). AUTOVON was an international military TTTN (Tandem Tie Trunk Network) that worked much like the PSTN (Public Switched Telephone Network). Under the control of the DOD (Department of Defense), AUTOVON was for unse- cure communications between all branches of the military. The topology of the network was highly secret and many of the COs (Central Offices) were in " hardened " buildings , or placed underground , in order that the network could survive a nuclear attack. AUTOVON telephones had an extra column of four buttons on the right side of the touchtone keypad. The "FO" key was for "Flash Override," the "F" key for "Flash," the "I" key for "Immediate," and the "P" key for "Priority" calls. AUTOVON was replaced by the DSN (Defense Switch Network), which is under the control of DISA (Defense Information Systems Agency). See also TTTN.

Auxiliary Disconnect Outlet

ADO. A device usually located within the tenant or living unit used to terminate the ADO cable or backbone cable. Source ANSI/TIA/EIA-570-A.

Auxiliary Equipment

See also Peripheral Device or Applications Processor.

Auxiliary Equipment Access

The ability of a telephone system to interface with (i.e. talk to) auxiliary equipment such as a paging system or dial dictation system.

Auxiliary Line

A telephone trunk in addition to the main number you rent from the phone company. Phone systems are often equipped for calls to hunt from a busy main number to one or more auxiliary lines (Incoming Service Group, or ISG). For example, the publisher's main office main number is 212-691-8215. But it also has 8216, 8217, 8218 and several unmarked or coded trunks. These are auxiliary lines and they don't receive their own billing or listing from the phone company. Sometimes, people have single line private lines which "appear" on their phone and no one else's. Sometimes they call these auxiliary lines. Sometimes these are called private lines. Sometimes they are also called terminal numbers.

Auxiliary Network Address

In IBM parlance, in ACF/VTM, any network address except the main network address, assigned to a logical unit which is capable of having parallel sessions.

Auxiliary Power

An alternate source of electric power, serving as backup for the primary power at the station main bus or prescribed sub-bus. An off-line unit provides electrical isolation between the primary power and the critical technical load; an on-line unit does not. These are government definitions: A Class A power source is a primary power source; i.e., a source that assures an essentially continuous supply of power. Types of auxiliary power service include: Class B: a standby power plant to cover extended outages (days); Class C: a quick-start (10 to 60 seconds) unit to cover short-term outages (hours); Class D: an uninterruptible (no-break) unit using stored energy to provide continuous power within specified voltage and frequency tolerances.

Auxiliary Ringer

This is a separate external telephone ringer or bell. It can be programmed to ring when a line or a telephone, or both, ring or when Night Service is turned on.

Auxiliary Service Trunk Groups

A category of trunk groups that provides selected services for customer or operators and terminates on announcement systems, switchboards , or desks. Examples include Directory Assistance, Intercept, Public Announcement, Repair Service, Time, and Weather.

Auxiliary Storage

A mass storage device capable of holding a larger amount of information than the main memory (i.e. RAM) of the computer or telephone system, but with slower access time. Examples include magnetic tape, floppy disks, etc.

Auxiliary Work State

A call center term. An agent work state that is typically not associated with handling telephone calls. When agents are in an auxiliary mode, they will not receive inbound calls.


ATM User-to-User.


The amount of time a computer or a telephone system is available for processing transactions or telephone calls. Here's a more technical definition: The ratio of the total time a functional unit is capable of being used during a given interval to the length of the interval; e.g., if the unit is capable of being used for 100 hours in a week, the availability is 100/168. Contrast this with the term Reliability.

In SONET, the basic Bellcore reliability criterion is an end to end two way availability of 99.98% for interoffice applications (0.02% unavailability or 105 minutes/year down time). The objective for loop transport between the central office and the customer premises is 99.99%. For interoffice transport the objective refers to a two way broadband channel, e.g. SONET OC-N, over a 250 mile path. For loop applications the objective refers to a two way narrowband channel, e.g. DS0 or equivalent. See Reliability.

Availability Reports

Availability reports show how often and for how long nodes, links or paths were unavailable due to outages between specified dates. They can be used to monitor network reliability and to calculate rebates for users.


In automatic call distribution language, an agent state, between calls, when an agent, having finished the previous transaction, returns to accept the next inbound caller. See also Availability.

Available Bit Rate

ABR. An ATM level of service that adjusts bandwidth according to congestion levels in the network. It does not guarantee a specific amount of bandwidth, and the end station must retransmit any information that did not reach the far end.

Available Channel

In the CDPD cellular mobile system, a Radio Frequency (RF) channel is available if it is an allocated channel that is not currently in use for either Cellular Digital Packet Data (CDPD) or non-CDPD-based wireless packet data service.

Available Line

In voice, video, or data communications, an available line is a circuit between two points that is ready for service, but is idle. Pretty obvious.

Available State

According to Bellcore, an available circuit state occurs when all of the following are true:

  1. The Bit Error Ratio (BER) is better than 1 in 10 to the nth power for a specific number of consecutive observation periods of fixed duration.

  2. Block Error Ratio (BLER) is better than 1 in 10 to the nth power under the same conditions.

  3. There are a specific number of consecutive observation periods of fixed duration without a severely errored unit time.

Available Time

From the point of view of a user, the time during which a functional unit can be used. From the point of view of operating and maintenance personnel, the available time is the same as the uptime, i.e., the time during which a functional unit is fully operational.

Avalanche Multiplication

A current-multiplying phenomenon that occurs in a semiconductor photodiode that is reverse- biased just below its breakdown voltage. Under such a condition, photocurrent carriers , i.e., electrons, are swept across the junction with sufficient energy to ionize additional bonds , creating additional electron -hole pairs in a regenerative action.

Avalanche Photo Diode

APD. A fiber optic transmission device. A light detector that generates an output current many times the light energy striking its face. A photodiode that shows gain in its output power compared to the optical power that it receives through avalanche multiplication (signal gain) of the current that flows through a photosensitive device. This type of diode is used in receivers requiring high light sensitivity. See APD.


The process by which an electrical signal is multiplied within a device by electron impact ionization.


  1. A graphical icon that represents a real person in a virtual reality system. When you enter the system, you can choose from a number of fanciful avatars. Sophisticated 3D avatars even change shape depending on what they are doing (e.g., walking, sitting, etc.).

  2. A common name for the superuser account on UNIX systems. The other common name is root.

Avaya Communication

Previously the Enterprise Networks Group of Lucent Technologies (originally Western Electric, the manufacturing arm of the AT&T Bell System), the spin-off of Avaya was officially announced July 3, 2000. Avaya manufactures voice, converged voice and data, customer relationship management, messaging, multi-service, networking, and structured cabling products and services. Lucent Technologies, minus Avaya, designs and delivers the systems, software, silicon and services for network service providers and large enterprises . "Avaya" is a made-up name, which is known as an "empty vessel" in the naming business. See also Lucent Technologies.


Advanced Voice Busyout. The local voice busyout feature that provides a way to busy out a voice port or a DS0 group (time slot) if a state change is detected in a monitored network interface (or interfaces). When a monitored interface changes to a specified state, to out-of-service, or to in-service, the voice port presents a seized/busyout condition to the attached PBX or other customer premises equipment (CPE). The PBX or other CPE can then attempt to select an alternate route. AVBO adds the following functionality to the local voice busyout feature:

  1. For Voice over IP (VoIP), monitoring of links to remote, IP-addressable interfaces by the use of a real time reporter (RTR).

  2. Configuration by voice class to simplify and speed up the configuration of voice busy- out on multiple voice ports.

  3. Local voice busyout is supported on analog and digital voice ports using channel- associated signalling (CAS).


Automatic Volume Control. In radio it maintains constant sound level despite undesired differences in strength of incoming signal.


Alternative Voice Data or Alternating Voice Data. AVD used to mean a voice circuit that would also handle data. See AVD Circuits. Now AVD means it's a normal switched analog phone line connected to which is a AVD modem, which lets you transfer bursts of fax, data and images between your voice conversation. The protocol mostly used is VoiceView. See AVD Circuits and DSVD.

AVD Circuits

Alternate Voice Data Circuits. Telephone lines which have been electrically treated to handle both voice and data signals. Typically used on leased overseas circuits to save money. See AVD.


The average and the mean are the same. What's different is the median. See Mean for a full explanation.

Average Business Day

ABD. The sum of the busy hour -data (usage, peg count, or overflow) recorded for each of the five busiest days of the week and divided by the total number of days being reported during any given basic data service month. Traditionally, Monday through Friday are the five busiest days of the week. However, traffic characteristics in a particular central office may produce high loads during the weekend . This average (5 days) figure is used in selecting the busy season months and the average busy season value.

Average Busy Season

ABS. Average Busy Season is the month's (normally three but not necessarily consecutive) with the highest average busy hour CCS per Network Access Line (NAL). Research suggests that these calling volumes are highly stable and thereby extremely predictable.

Average Call Duration

Divide the total number of minutes of conversation by the number of conversations. Bingo, that's your average call duration.

Average Customer Arrival Rate

Represents the number of entities ( humans , packets, calls, etc.) reaching a queuing system in a unit of time. This average is denoted by the Greek letter lambda. One would prefer to know, if possible, the full distribution of the calls arriving.

Average Delay

The delay between the time a call is answered by the ACD and the time it is answered by a person. This typically includes time for an initial recorded announcement plus time spent waiting in queue. Average delay can be chosen as the criterion for measuring service quality.

Average Handle Time

AHT. The period of time an employee is occupied with an incoming call. This is the sum of talk time and after-call-work time.

Average Holding Time

The sum of the lengths (in minutes or seconds) of all phone calls during the busiest hour of the day divided by the number of calls. There are two definitions. The one above refers to average speaking time (it's the more common one). There's a second definition for "average holding time." This refers to how long each call was on hold, and thus not speaking. This second definition is typically found in the automatic call distribution business (ACD). Check before you do your calculations.

Average Latency

The time required for a disk to rotate one-half revolution.

Average Load

The traffic load obtained by averaging a series of hourly loads. An average load may be further defined as average carried load, average offered load, etc. This term is not to be confused with load that is inherently an average of all the instantaneous loads over a basic time interval such as an hour.

Average Pulse Density

In T-1 bipolar transmissions, refers to the number of "1" pulses per "0" conditions and is usually tied to a maximum number of "0"s in a row (i.e., FCC Part 68 requires 12.5% pulse density and no more than 80 consecutive "0"s where as AT&T Pub 62411 uses a formula and no more than 15 consecutive "0"s).

Average Speed Of Answer

ASA. How many seconds it takes an operator on average to answer a call.

Average 10-High Day

ATHD. A mathematical average of the data generated during the 10-high day busy hour. This is the same hour for all ten days and generally will occur during the busy period. However, predictable recurring heavy traffic days which occur outside the busy period should be included.

Average Picture Level

APL. In video systems, the average level of the picture signal during active scanning time integrated over a frame period. It is defined as a percentage of the range between blanking and reference white level.

Average rate

Average rate, in kilobits per second (kbps), at which a given virtual circuit can transmit.

Average Rate of Transmission

See Effective Transmission Rate.

Average Talk Time

ATT. The average length of a complete customer transaction over the phone.

Average Transfer Delay

Average time between the arrival of a packet to a station interface and its complete delivery to the destination station.


Audio Video Interleaved. File format for digital video and audio under Windows. Use the "Media Player," which comes with Windows, to play AVI files. The AVI file format is cross-platform compatible, allowing .AVI video files to be played under Windows and other operating systems. AVI is not a definition on compression but a rule on file formatting. It is primarily used with the Microsoft Windows operating systems. Its main problem is its huge file size , i.e. it encodes analog video into a huge digital file that eats up your hard disk. Therefore several companies have developed their own procedure for compressing AVI files. MJPEG, Cinepark, and Indeo from Intel are some of the popular methods used to compress AVI files. They use the "intracoding" method for compression and are widely used to edit video images frame by frame. But they are inferior to MPEG in terms of compression ratio, image quality and compatibility. MPEG is an abbreviation of Moving Picture Experts Group, one of the international standard organizations. MPEG is a rule concerning file format and compression method. Since it is an international standard, it is compatible with several operating systems including Windows. Many consumer devices such as CD player and DVD player support MPEG-1 and MPEG-2 formats. This makes MPEG easy to use. The MPEG compression ratio is very high because it uses intercoding, a superior compression technique to intracoding. See MPEG.


Audio Video Kernel. DVI (Digital Video) system software designed to play motion video and audio across hardware and operating system environments.


Automatic Vehicle Location ” not an elegant name, but an umbrella description for the fleet management version of mobile telematics, which involves integrating wireless communications and (usually) location tracking devices (generally GPS) into automobiles. The best known example of mobile telematics is GM's OnStar system, which automatically calls for assistance if the vehicle is in an accident . These systems can also perform such functions as remote engine diagnostics, tracking stolen vehicles, provide roadside assistance, etc. Best known operators of AVL services (mobile telematics for fleets) are Qualcomm's OmniTRACS division and Teletrac. They generally involve integrating wireless communications and location sensing technology (frequently GPS) into commercial vehicles, to allow mobile communications, automated dispatching, cargo tracking, etc.

Avoidable Costs

A wonderful concept used by the regulated telephone industry. It refers to those costs which would be avoided (i.e. not incurred) if the service were not offered. Examples of costs to avoid are maintenance, taxes, labor, and other direct costs. The concept of Avoidable Costs is to allow the phone industry the justification to price a competitive service very low.

Avoidance Routing

The assignment of a circuit path to avoid certain critical or trouble-prone circuit nodes.


A pound of feathers weighs more than a pound of gold. Feathers are weighed by "avoirdupois" weight measure, which has 16 ounces to a pound, while gold is weighed in "troy" measure, which only has 12 ounces to a pound .


Automated Voice Response System. See IVR and Voice Response System.


Audio-Video Support System. DVI (Digital Video) system software for DOS. It plays motion video and audio.


  1. Administrative Weight. The value set by the network administrator to indicate the desirability of a network link. One of four link metrics exchanged by PTSPs to determine the available resources of an ATM network.

  2. Admin Workstation. A personal computer used to monitor the handling of calls in the ICM system. The AW also can be used to modify the system configuration or scripts.


Area-Wide Centrex.


American Wire Gauge. Originally known as the Brown and Sharpe (B&S) Wire Gauge. The U.S. standard measuring gauge for non-ferrous conductors (i.e., non-iron and non- steel ), AWG covers copper, aluminum, and other conductors. Gauge is a measure of the diameter of the conductor. The AWG numbering system is retrogressive (i.e., backwards ): The higher the AWG number the thinner the wire. This is due to the fact that the AWG number originally indicated the number of times the copper wire was drawn through the wire machine to reduce its diameter. For example, a 24-gauge wire was drawn through the wire machine 24 times; therefore, it is thinner than a 22-gauge wire, which was drawn through the wire machine only 22 times. A 24-gauge (AWG) wire has a diameter of .0201 in. (.511 mm), a weight of 1.22 lbs/ft (1.82 kg/km), a maximum break strength of 12.69 lbs (5.756 kg) and D.C. resistance ohms of 25.7/1000 ft (84.2 km). For example, heavy industrial electrical wiring may be No. 2; homes are typically wired with No. 12 or No. 14. Telephone systems typically use No. 22, No. 24 or No. 26. The thicker the wire, the more current it can carry farther without creating heat and without suffering attenuation (signal or power loss) due to resistance. You need thicker phone cabling when your phones are farther away. Also, you need thicker wire when transmitting at higher frequencies such as would be the case in a data application (e.g. 10/100Base-T); high-frequency signals attenuate to a greater extent than do low-frequency signals. Some vendors save money by installing systems with thin wire. Make sure you specify.


An amateur radio implementation of the X.25 protocol. Used by some private VANs (Value Added Networks) to avoid PTT (Post, Telephone and Telegraph Administration) monopolies (and thus high prices) on X.25 transmission and switching.

Axial Propagation Constant

In an optical fiber, the propagation constant evaluated along the optical axis of the fiber in the direction of transmission. Note: The real part of the axial propagation constant is the attenuation constant. The imaginary part is the phase constant.

Axial Ratio

Of a wave having elliptical polarization, the ratio of the major axis to the minor axis of the ellipse described by the tip of the electric field vector.

Axial Ray

A ray that travels along the axis of an optical fiber.

Axial Slab Interferometry

Synonym for Slab Interferometry.


The center of an optical fiber.

AZ/EL Mount

Antenna mount that requires two separate adjustments to move from one satellite to another.


The horizontal angle which the radiating lobe of an antenna makes in angular degrees, in a clockwise direction, from a north-south line in the northern hemisphere. In the southern hemisphere, the reference is the south-north line. Azimuth actually involves a lot more than antennas. For example, it covers the alignment of a recording head in a tape recorder.

Azimuth Beam Width

The angular measurement of an antenna pattern as viewed along the horizon. It is sometimes called the "horizontal beam width."

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