Home Tandem-Hz

Home Tandem

A tandem of a higher office class to which another tandem or an end office has a final trunk group . Home tandems may exist for all or defined subsets of tandem switched traffic.

Home Zone

Cell phone service that is configured by the cell phone carrier to offer dual pricing ” one price for calling from your phone (i.e. cheap) and another, more expensive price for calling from outside your home ” like a normal cell phone. At home you may plug your cell phone into a home phone system. The idea of home zone is for your cell phone company to sell more phones, by competing with landlines.

HomePNA

Home Phoneline Networking Alliance. An association of companies working toward the adoption of a single, unified phoneline networking standard and bringing to market a range of interoperable home networking solutions using in-place phone wiring. HomePNA solutions are intended to be plug-and-play for networking of multiple PCs, peripherals (e.g., printers, scanners and video cameras ), multi-player network games , home automation devices (e.g., environmental control and security systems), digital televisions and digital telephones. An all-purpose Home Area Network (HAN) using existing telephone wiring, the HomePNA solution also is intended as a means of shared access to IP voice and video networks, the IP-based Internet, and the conventional circuit-switched Wide Area Network (WAN). Network access technologies are intended to include analog, ISDN and xDSL local loops . Initial efforts are directed at a technology that will support spatial separation of nodes by as much as 500 feet, which represents a home of up to 10,000 square feet (which is bigger than my home, and probably bigger than yours, unless you are Bill Gates and live in a monstrosity of a castle, in which case you probably already have an ATM-based LAN with SONET fiber optics pipes running at 10 Gbps, but I digress), and running at data rates of 1 Mbps. Frequency Division Multiplexing (FDM) is intended to support simultaneous voice and data traffic; frequency ranges are intended to avoid interference from devices (e.g., refrigerators and air conditioners) found in the home. HomePNA solutions are based on an Ethernet derivative, running at 1 Mbps at frequencies above 2 MHz using a proprietary compression technique from Tut Systems, and using the CSMA/CD protocol native to Ethernet; speeds of 10 Mbps are planned into the future, with the theoretical potential being as much as 100 Mbps. Members include 2Com, AT&T, Compaq, Hewlett-Packard, IBM, Intel, Lucent and Tut Systems. www. homepna.org. See also Ethernet, FDM, ISDN, SONET and xDSL. www.homepna.org

Homeostasis

A physiological constancy or equilibrium maintained by self-regulating mechanisms. In short, the state of a system in which the input and output are exactly balanced, so there is no change.

Homes Passed

An expressed of the number of dwellings that a CATV provider's distribution facilities pass by in a given cable service area and an expression of the market potential of the area.

Homing

1. When you dial a long distance number, your central office will choose a special set of trunks to send your call onto the next switching center for movement through the nationwide toll system. Those trunks are said to be the homing trunks for your central office. In other words, your central office is said to home on these trunks. If you're consistently encountering lousy long distance lines (and so are others on your central office), then ask your telephone company to check these trunks out.

2. Returning to the starting position, as in a rotary stepping switch when its connection is released.

Homo

1. The Greek prefix meaning the same.

2. Home Office Mobile Office. See also SOHO, which stands for Small Office Home Office.

Homogeneous Networks

Composed of similar hardware from the same manufacturer.

Homologation

Conformity of a product or specification to international telephony connection standards. What this means in simple language is that you have submitted your product to a regulatory agency or a government testing agency in a foreign country and they have said that your product is OK for use and sale in that country and is allowed to be connected to the local phone system. In short, your product has now been homologated in that country.

Honey Pot

A honey pot is a decoy server attached to the Internet designed to attract hackers' attention. The honey pot gives the owner of a targeted server the chance to analyze the attack, develop a strategy to thwart the attack and to block access without causing any damage to the main server.

HoneyDoThis List

Gerry Friesen's wife Paula created this term . It derives from her frequent requests to Gerry, "Honey Do This." "Honey Do That."

Honeycomb Coil

A type of inductance in which the turns do not lie adjacent to each other.

Honeymoon

It was the accepted practice in Babylon 4,000 years ago that for a month after the wedding , the bride's father would supply his son-in-law with all the mead he could drink. Mead is a honey beer, and because their calendar was lunar based, this period was called the "honey month" or what we know today as the honeymoon.

Hook-up Wire

A wire used for low current, low voltage (under 1000 volts ) applications within enclosed electronic equipment.

Hookemware

Free software that contains a limited number of features designed to entice the user into purchasing the more comprehensive version. See also Hyperware, Meatware, Shovelware, Slideware and Vaporware.

Hooker

The term "hooker," meaning a prostitute, honors U.S. Army General Joseph Hooker, whose penchant for war was matched only by his predilection for paid female companionship. In New Orleans during the Civil War, Hooker spent so much time frolicking with ladies of the evening that the women came to be called "Hooker's Division." Eventually, these specialized "troops" became known simply as "hookers."

Hookflash

Momentarily depressing (up to eight tenths of a second) the hookswitch of a telephone instrument can initiate various services such as calling the attendant, conferencing calls, transferring calls or answering a call coming in on a line equipped with call waiting. In ISDN, a hookflash signals the System Adapter to perform an operation, such as placing a call on hold. To hookflash, simply depress and release the receiver button. By default, the Hayes ISDN System Adapter recognizes a hookflash when the receiver button is depressed less than 0.8 of a second. You can change the default. See Hookswitch.

Hooking Signal

An on-hook signal of 0.1 to 0.2 second duration used to indicate that a subscriber intends to initiate a new process such as "add-on."

Hookswitch

Also called switchhook or switch hook. The place on your telephone instrument where you lay your handset. A hookswitch was originally an electrical "switch" connected to the "hook" on which the handset (or receiver) was placed when the telephone was not in use. The hookswitch is now the little plunger at the top of most telephones which is pushed down when the handset is resting in its cradle (on-hook). When the handset is raised, the plunger pops up and the phone goes off-hook. Momentarily depressing the hookswitch (up to 0.8 of a second) can signal various services such as calling the attendant, conferencing or transferring calls. See Hookflash and Hooking Signal.

Hookswitch Dialing

You can make phone calls by depressing the hookswitch carefully . If you push it five times, you dial five. Push it ten times you dial 0. Some coin phones discourage hookswitch dialing. Some don't.

Hoot'n' Holler

Hoot'n'Holler are special 24- hour a day phone circuits which stay open 24-hours a day, seven days a week. Anyone picking up a phone on the circuit can listen and talk to whoever's on the line, or whoever might be within earshot. The idea is that to get someone to speak to you, you "hoot and holler," i.e. make a noise. A hoot'n'holler circuit is also called a Junkyard Circuit, Holler Down, Shout Down, Open Speech Circuit, Squawk Box System, FP or Full Period (as in FP 123456 circuit #). Hoot'n'Holler is a circuit consisting of 4 wires (2 pair ” a transmit pair and a receive pair). Technically, this is how it works: Audio energy present on the transmit pair at any location will appear on the receive pair of all the other locations, usually a multipoint circuit. The transmitted audio will not return on the receive pair of the originating location. Hoot'n'Holler circuits are voice conferencing oriented party lines and are non private by nature. There is no signaling on a hoot and holler circuit except when one "shouts down" to open speakers and "listens" at the distant out points. A Hoot'n'Holler circuit is a dedicated full time voice network. Individual four wire "drops" are connected via various bridging mechanisms. These "bridges" can be analog or digital and act as mix minus devices ( mixes everyone else minus yourself). They provide all drops with connectivity with each other.

Hop

1. Each short, individual trip that packets (or e-mail messages) make many times over, from router to router, on their way to their destinations.

2. A change of Radio Frequency (RF) channel used to carry the Cellular Digital Packet Data (CDPD) data for a channel stream.

Hop by Hop Route

A route that is created by having each switch along the path use its own routing knowledge to determine the next hop of the route, with the expectation that all switches will choose consistent hops such that the call will reach the desired destination. PNNI (Private Network-Network Interface) does not use hop-by-hop routing.

Hop Channel

A Radio Frequency (RF) channel that has been declared a candidate for carrying a Cellular Digital Packet Data (CDPD) channel stream after a channel hop.

Hop Count

The number of hops it will take for a packet to make it from a source to a destination. In short, the number of nodes (routers or other devices) between a source and a destination. In TCP/IP networks, hop count is recorded in a special field in the IP packet header and packets are discarded when the hop count reaches a specified maximum value.

Hop Off

When you make a phone call on the Internet you can call from one phone attached to the Internet to another phone attached to the Internet or you can call from one phone attached to the Internet and, at the other end, go into a PC stuffed with voice and switching cards and which is attached to local phone lines. The process of leaving the Internet is called "Hop Off."

Hop Sequence

The carefully coordinated sequence by which radio transmitters and receivers hop from on frequency to another, hop sequence is used in FHSS (Frequency Hopping Spread Spectrum) systems. FHSS is used extensively in Wireless LANs and certain PCS (Personal Communications Systems) cellular systems. See also FHSS.

Hops

Term describing the number of times a message traverses different nodes.

HOPS

Hardwire Order Processing System.

Horizontal

1. H. In television signals, the horizontal line of video information which is controlled by a horizontal synch pulse.

2. Descriptive of the side of a North American wire Distributing Frame on which terminal blocks are mounted horizontally; this is the side equipment is terminated on, as opposed to the "vertical side," on which cables terminate in vertically mounted blocks. In some locations, frames of horizontal blocks only are called Horizontal Intermediate Distributing Frame, or HIDF. Compare to VIDF.

Horizontal Beamwidth

See Azimuth Beamwidth.

Horizontal Blanking Interval

The period of time during which an electron gun shuts off to return from the right side of a monitor or TV screen to the left side in order to start painting a new line of video.

Horizontal Cable

Defines the cable used to link the communications closet / room with individual end user devices. Horizontal cabling stays typically on one floor. That's why it's called horizontal.

Horizontal Cross-Connect

A cross-connect in the telecommunications closet or equipment room to the horizontal distribution cabling.

Horizontal Distribution Frame

Located on the floor of a building. Consists of the active, passive, and support components that provide the connection between inter- building cabling (i.e. cabling coming from outside the building) and the intra-building cabling for a building.

Horizontal Interval

The sum of Horizontal Retrace.

Horizontal Link

An ATM term. A link between two logical nodes that belong to the same peer group.

Horizontal Output

The amplifier that amplifies the horizontal output sync signal in a TV or monitor. The output runs through a deflection yolk. This creates magnetic fields that control tracing of the CRT beam sideways . A vertical amplifier does the same for the up and down tracing of the CRT beam. A TV's horizontal output frequency is 15.73425 kHz. On some TVs you can hear the high-pitched sound of the horizontal output circuitry when you turn on the equipment.

Horizontal Retrace

A video term. The return of the electron beam from the right to the left side of the raster after the scanning of one line.

Horizontal Resolution

Detail expressed in pixels that provide chrominance and luminance information across a line of video information.

Horizontal Scan Rate

The frequency in Hz (hertz) at which the monitor is scanned in a horizontal direction; high horizontal scan rates produce higher resolution and less flicker. Thus, the EGA horizontal scan rate is 21.5Hz, while the VGA standard scan rate is 31.4Hz. Some displays now offer even higher scan rates, as much as 70 Khz. See Monitor.

Horizontal Sync

A video term. Horizontal sync is the -40 IRE pulse occurring at the beginning of each line. This pulse signals the picture monitor to back to the left side of the screen and trace another horizontal line of picture information. See Interlace.

Horizontal Wiring

The portion of the wiring system extending from the work- station's outlet to the BHC (Backbone to Horizontal Cross-Connect) in the telecommunications closet. The outlet and cross-connect facilities in the telecommunications closet are considered part of the horizontal wiring. See Horizontal Wiring Subsystem.

Horizontal Wiring Subsystem

The part of a premises distribution system installed on one floor that includes the cabling and distribution components connecting the riser subsystem and equipment wiring subsystem to the information outlet via cross connects, components of the administration subsystem.

Horn

In radio transmitting, a waveguide section of increasing cross-sectional area used to radiate directly in the desired direction or to feed into a reflector that forms the desired beam.

Horn Alert

HA. A cellular car phone feature that automatically blows the car's horn if a call is coming in.

Horsepower

A horespower typically measures the power of an internal cumbustion engine. A unit of power equivalent to 550 foot pounds per second or to 746 watts. James Watt coined the term after the part-time miner observed that the average horse raised 330 pounds of coal 100 feet in one minute. Thus 33,000 foot pounds became one horsepower.

Horton

A software program which provides an automatic method for creating a directory of e-mail addresses. Users can look up electronic addresses via a search key which can be a fragment of a person's name .

Hose And Close

A pattern of behavior exhibited by phone tech-support people who spout a bunch of jargon you don't understand, ask you to perform a bunch of procedures you don't follow, and then abruptly hang up. This definition from Wired Magazine.

Hosed

The system is hosed means that it no longer works. The expression comes from what happens to someone who has has received the full force of a fireman's water hose, as in a street demonstration.

Host

1. An intelligent device attached to a network.

2. A mainframe computer.

3. A computer with full two-way access to other computers on the Internet. A host can use virtually any Internet tool, such as WAIS, Mosaic and Netscape.

Host/Remote

Describes a scenario where the remote is a serving end office that does not have recording capabilities and, therefore, allows a host end office to record for it.

Host Apparent Address

A set of internetwork layer addresses which a host will directly resolve to lower layer addresses.

Host Based Firewall

A hostbased firewall is a firewall system that includes a bastion host (a general-purpose computer running firewall software). A host based firewall usually includes a circuit-level gateway, an application level gateway, a hybrid of both gateways, or a stateful inspection firewall.

Host Bus Adapter

HBA. A printed circuit board that acts as an interface between the host microprocessor and the disk controller. The HBA relieves the host microprocessor of data storage and retrieval tasks , usually increasing the computer's performance time. A host bus adapter (or host adapter) and its disk subsystems make up a disk channel.

Host Carrier

The cellular operating company a subscriber from another cellular system would be billed roamer charges.

Host Computer

1. A host computer is one that provides services and information to a series of other devices. Host computers were traditionally mainframes that provided large and complex services to a network of smaller terminals. For this reason, host computers are often referred to as large servers. For example, airline booking from individual terminals would link into a central host to process the various transactions. IBM is still the dominant supplier of host computers for transaction processing. On the Internet, the term ~host'~ means any computer that has full two-way access to other computers on the Internet. A host has a specilic local or host number that, together with the network number, forms its unique Internet protocol address.

2. In the context of the Internet. this is a computer that has access to other computers on the World Wide Web.

Host Digital Terminal

See HDT.

Host Interactive Voice Response

A voice response system that can communicate with a host computer, typically a mainframe. Applications which can be produced include bank-by-phone, reservations -by-phone, etc.

Host Name

The name given to a mainframe computer.

Host Name Resolution

A mechanism that provides static and dynamic mechanisms for resolving host names into numeric addresses. The Internet Name Server Protocol accesses an Internet name server that provides dynamic name-to-number translation (this process is specified in IEN 116). The Domain Name Protocol accesses a Domain Name Server that provides dynamic name-to-number translation (this process is specified in RFC- 1034 and RFC-1035). A static local host table can also be accessed for name-to-number translation.

Host Number

The part of an internet address that designates which node on the (sub)network is being addressed. See Domain.

Host Processor

Same as Host Computer.

Host Server

A device which connects to a LAN and then allows a computer, which cannot directly support the LAN protocols, to connect to it, providing all necessary LAN support.

Host Site

In the transfer of files, the host site is the location receiving a file. When two individuals are exchanging files, the one who receives the file first would be the host, the other would be considered the remote.

Host Switch

A central office switching system which provides certain functions to a smaller switch located remotely.

Host Table

1. A list of TCP/ IP hosts along with their IP addresses.

2. In Windows 95, the host table is HOSTS or LMHOST file that contains lists of known IP addresses mapped to host names or NetBIOS computer names.

3. An ASCII text file where each line is an entry consisting of one numeric address and one or more names associated with that address. Host tables are used to resolve host- names into numeric addresses.

Hosted

See Hosting.

Hosted PBX

Someone else owns my PBX and rents me space, time and telecommunications services on it. That PBX is typically away from my office or offices. It's joined to me by various types of phone lines, including T-1. Essentially hosted PBX is a fancy new name for what we used to call Centrex, when the phone company owned the PBX and rented me space, time and telephone services on it. See also Centrex and Hosting.

Hosting

I have a web site. It's called www.HarryNewton.com. For all my friends to be able to read it, my web site has to be connected full-time to the Internet. I can do that myself if I have a full-time high-speed connection to the Internet and if I have the computing equipment and if I the full-time people to make sure it's working 100% of the time and, and, and. But most of us can't afford that. A whole bunch of businesses have sprung up to run web sites for other people, like me. These businesses are called web site hosters, web hosters, or just hosters . And the service they provide is called hosting. They typically offer four types of hosting:

1. Shared Hosting Web sites hosted on shared servers. This is what I have. I'm one web site on a server which also hosts other peoples' web sites. Clearly, this is an economical solution for people like me who have simple or moderately accessed sites. Mine is only two pages and not many people visit it. There's not much to see.

2. Dedicated Hosting Let's say my web site was larger and accessed more frequently by more people. Then clearly I'd want a server dedicated to me. This way I could have more people coming to my site and they'd get faster service. With dedicated hosting, I get my own server dedicated to me. This solution provides greater server and network resources than shared hosting and allows for hardware configuration to optimize my site's performance.

3. Co-located Hosting Let's say that I don't want the computer my hoster provides. Let's say that I want to use my to use own special computer (for whatever reason). But I want my computer on the web hoster's site for two reasons: First, the hoster can connect my computer (i.e. my Web site server) to much faster telecom lines than I can. Most often, hosters site themselves at major Internet switching sites on T-3 rings. See MAE. Second, the hoster will have people on duty 24-hours a day, 365 days a year. So, if my server goes down, he can have someone look at it quickly ” even in the middle of the night. People who like this service tend to have "sophisticated mission-critical applications," for example ecommerce.

4. Application Hosting In the three services above, the hoster has no responsibility for what the customer has actually put on his web site. Ecommerce or porn, he doesn't care.

With application hosting, the web hoster cares. He takes your application and works with you, sort of a combination web hoster / consultant/ webmaster. He might help you get an ecommerce site up, or a corporate email system, or a Lotus Notes collaboration system.

Hot

Live. It's on and has power flowing . Live wire. A conductor carrying a signal is said to be a hot conductor, i.e. the wire carrying the signal or the ground as opposed to the neutral or ground wire.

Hot And Ground Reversed

In AC electrical power, the correct connection of the Hot and Ground wires is reversed. This is an extremely dangerous condition because the GROUND path will rise to 129 volts and can present a lethal shock hazard to anyone in contact with equipment powered from this outlet or any outlet using the same ground path. See Hot and Neutral Reversed.

Hot And Neutral Reversed

Also called reversed polarity. A symptom of poor AC electrical wiring. In this case the correct connection of the Hot and Neutral conductors is reversed. Dangers include increased leakage current, and damage to electronic equipment or motors and appliances requiring correct polarity. See Hot And Ground Reversed.

Hot Chat

An Internet term. Sex talk, in real time, online, usually between two or more consenting people (through not necessarily adults).

Hot Cut

The conversion from an old to a new phone system which occurs instantly as one is removed from the circuit and the other is brought in. There are advantages and disadvantages to Hot Cuts. For one, they're likely to be much more dangerous than a Parallel Cut, in which the two phone systems run side by side for a month or so. Also known as Flash Cut. See Cutover for a longer explanation.

Hot Desk

An employee of a company no longer has a permanent office. He works out of his home, visits customers and communicates with the office through fax and electronic mail. Occasionally that person finds it necessary to visit an office of the company. He is allocated a desk and perhaps an office for his stay. That stay might be as short as an hour or as long as several weeks. Once he checks out, someone else gets the desk. This arrangement is called a "Hot Desk."

Hot Desking

Open office spaces with easily movable furniture and partitions that support on-the-spot group meetings or quickly assembled individual work areas.

Hot 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.

Hot Dog

The archetype of American food. The phrase 'hot dog' originated in the nineteenth century. It was a running joke that sausages were often made not from beef or pork, as claimed by those who made them, but from whatever stray animals were at hand, especially stray dogs. Students at Yale University in the 1890s referred to sausages as dogs, and the lunch wagon where they were sold as a dog wagon. Served hot, in a bun, the sausages were thus hot dogs.

Hot Fix

A feature of Novell's NetWare LAN (local area network) operating system in which a small portion of the hard disk's storage area is set aside as a "Hot Fix Redirection Area." This area is set up as a table to hold data that are "redirected" there from faulty blocks in the main storage area of the disk. It's a safety feature.

Hot Insertion

An application feature that allows users to modify or update scripts "on the fly," without closing and restarting the application.

Hot Key Combination

A combination of keys on the keyboard that are pressed down simultaneously to make the computer perform a function. For example, the Ctrl, Alt, Del hot-key combination will warm boot an MS-DOS computer.

Hot Line

A private line dedicated between two phones. When you pick up either phone or do some act of signaling (like push a button), the other phone rings instantly. Hot lines are useful in emergencies and other areas where time is of the essence ” e.g. trading currencies. The telephone hot line between the White House and the Kremlin was established in 1984. Previously, a teletypewriter hot line was used. The problem with a hot line is that it's one circuit. Cut it and you're out of business. The White House/Kremlin circuit apparently used to pass through Finland, where he has been accidentally cut by farmers. I'm guessing that the circuit now has several backups . If one goes, they can switch to another.

1. a direct telecommunications link, as a telephone line or Teletype circuit, enabling immediate communication between heads of state in an international crisis: the hot line between Washington and Moscow.

2. a telephone service enabling people to talk confidentially with someone about a personal problem or crisis.

3. a telephone line providing customers or clients with direct access to a company or professional service. Also, hotline.

Hot Line Service

When you pick up the phone, you're automatically connected with a phone number. Such Hot-Line Service on a PBX typically gets you emergency service, etc. See also Hot-Line.

Hot Links

A methodology that references and can connect information from one document to another, regardless of the type of application used.

Hot List

A gopher or Web file that lets you quickly connect to your favorite pre-selected page. Appropriately named. The way it works: You connect to a home page. You decide you'd like to return at some other time. So you command your internet surfing software to mark this web site on your hot list (also called marking it with a "bookmark." Next time you want to return to that web site, you simply go to your hot list or your bookmarks, click on which one you want. And bingo, you're there. A hot list is also known as a bookmark. Most Web browsers have book marks or hot lists.

Hot On Neutral, Hot Unwired

In AC electrical power, the HOT wire is connected to the NEUTRAL terminal of the outlet and the HOT terminal in UNWIRED. Dangers include shock hazard from excessive leakage current and fire hazard. Depending on other conditions, equipment may or may not operate .

Hot Plug

When a system component (e.g., a computer disk drive) fails, it may be replaced without turning the system off. During this period, the system's activity is suspended , however. Also known as a Warm Swap, it is unlike a Hot Swap, during which the system remains active. See Hot Swap.

Hot Plugging

The ability to add and remove devices to a computer while the computer is running and have the operating system automatically recognize the change. Two new external bus standards ” Universal Serial Bus (USB) and FireWire support hot plugging. This is also a theoretical feature of PCMCIA cards.

Hot Potato Routing

In Hot Potato Routing, or deflection routing, the nodes of a network have no buffer to store packets in before they are moved on to their final predetermined destination. In normal routing situations, when multiple packets contend for a single outgoing channel, packets that are not buffered are dropped to avoid congestion. But in hot potato routing, each packet that is routed is constantly transferred until it reaches its final destination because the individual communication links cannot support more than one packet at a time. The packet is bounced around like a "hot potato," sometimes moving further away from its destination because it has to keep moving through the network.

Hot Racking

A Navy term referring to the practice in submarines of having sailors sleep in the same bunk at different times. This occurs because of the shortage of bunks on submarines. Hot racking is the reason the US Navy gave in May of 1995 for vetoing the idea of having women serve on crowded submarines.

Hot Redundancy

A term used in conjunction with very critical telecom and computing systems, such as 911 service. With Hot Redundancy, the component or the system runs in parallel with an identical "twin." Should one twin fail, the other is already running and provides full service without interruption.

Hot Restart

Imagine a corporate telephone system, perhaps a PBX or an ACD. It's handling phone calls to and from customers every second of the day. It's mission critical. You can't allow it to crash for even a second a day. But phone systems are nothing more than specialized computers with specialized software. They will crash or lock up just like your PC, though perhaps not as often. But they will crash and lock up. What happens when your PC crashes and locks up? You will lose data. You will probably then reboot your PC, probably from its hard disk. This will cost you anywhere from 30 to 60 seconds. You can tolerate this on your PC. You can't tolerate this on your phone system. An integral part of most phone systems' software is a feature called "Hot Restart." When the phone system's software crashes or locks up, there is "Hot Restart" software that enables the phone system to restart itself (another word for reboot) without losing the phone calls in progress or without taking 30 to 60 seconds to load a new operating system from hard disk or tape. How this exactly is done seems to vary from one telephone system maker to another. Some may keep an operating system in RAM. Some may keep two identical processors chugging away simultaneously and switch from one to another, when things go awry. How manufacturers do "Hot Restarts" is something of a trade secret.

Hot Sparing

A technique whereby the disk subsystem, when a disk's recoverable error rates excede some predetermined threshold, begins to copy data from the failing disk to a spare one. If the copy operation succeeds, before the disk fails for good, the subsystem switched to the spare and marks the failing disk unusable.

Hot Spot

See Hotspot.

Hot Standby

Backup equipment kept turned on and running in case some equipment fails. Also known as a Hot Spare. See Data Center.

Hot Swap

The process of replacing a failed component ” e.g. a RAID drive ” while the rest of the system (in this case, the disks) continues working and continues to provide function normally, i.e. providing data to the network users and providing a place for them to store their data. See Hot Swappable and Raid.

Hot Swappable

The ability of a component (such as a redundant power supply) to be added to or removed from a device (for instance, a repeater) without powering down the device, thus providing a maximum uptime.

Hot Wire

The ability to connect power to peripherals. Technologies capable of this include PCMCIA, USB and IEEE 1394.

Hotel

See Carrier Hotel.

Hotel/Motel Console

A specialized PBX console or a normal console programmed to work specifically in hotels and motels. The console will often show room status information.

Hoteling

Corporations get rid of permanent offices and instead assign full-time workers to a new office or cubicle each day, depending on who's in the office. Workers also have permanent lockers where they can store their files. Workers typically carry their lap- tops, cell phones and pagers with them. Hoteling works with companies whose employees spend a great deal of time outside the office visiting clients, customers and suppliers and working from home. Hoteling's advantage is that it prevents a company from having to keep lots of empty offices when so many people work at home or on flexible schedules. See Telecommuting.

Hotfix

A Novell program that dynamically marks defective blocks on the hard disk so they will not be used. See Hot Fix.

Hotjava

Java is a programming language from Sun Microsystems designed primarily for writing software to leave on World Wide Web sites and downloadable over the Internet to a PC owned by you or me. HotJava, its brother, is another piece of software installed on a Web browser at your desktop. HotJava enables Java programs delivered over the Web to run on your desktop PC. In short, Java is the programming language the programs on the Web are written in. HotJava is the software that will sit on your PC. Java is basically a new virtual machine and interpretive dynamic language and environment. It abstracts the data on bytecodes so that when you develop an app, the same code runs on whatever operating system you choose to port the Java compiler/interpreter to. What's a Java application? According to Wired Magazine, point to Ford Motor Company's website today, for instance, and all you'll get are words and pictures of the latest cars and trucks . Using Java, however, Ford could relay a small application (called an applet) to a customer's computer (the one on your desk which are using the surf the Internet). The customer could then customize options on an F-series pickup while calculating the monthly tab on various loan rates offered by a finance company or local bank. Add animation to these applications and you could get to "drive" the truck.

Hotline

There are several definitions. In the cellular business, a hotline is a system restriction that allows a cellular customer to call only one prearranged number. In the land- line phone business, a hotline is often a dedicated line. But it may also be a phone which only dials one number. In this case it's often call a virtual private line. See Hotline Virtual Private Line Service. For a longer explanation, see Hot Line.

Hotshot dialer

A piece of equipment used to create a hotline or ring-down circuit. A hotline is when one phone rings another without dialing (think of the Batphone to Commissioner Gordon's office, or the hotline between Washington and Moscow). The dialer automatically dials the number when the handset is lifted.

Hotspot

1. A hotspot (also spelled hot spot) is a small geographic area of several hundred square feet in which you can get access to a 802.11b wireless local area network. You'll need a PC or a laptops that has a 802.11b wireless card. Hot spots exist in homes, airport lounges, libraries, coffee shops , boardrooms, businesses, etc. . Businesses are adding Wi-Fi networks to allow for easy Internet access from conference rooms and temporary work stations . Businesses are looking to these 802.11b networks (also called WiFi) to avoid the hefty costs in both time and money of wiring an office.

2. An embedded hyperlink is a hyperlink that is in a line of text. A hotspot is the place in a document that contains an embedded hyperlink. A hotspot is a graphically defined area in an image that contains a hyperlink. An image with hotspots is called an image map. In browsers, hotspots are invisible. Users can tell that a hotspot is present by the changing appearance of the pointer.

House Cable

Communication cable within a building or a complex of buildings and owned by the local phone company. House cable comes from the terminal box in the basement or the nearby outside pedestal box and goes straight to the apartment or house.

Often it's not terminated. Thus, a technician installing a phone line will often have to break into a house cable and search around for an unused cable pair. In a multi-story building, a house cable is called a riser cable. Thanks to John Arias of Bell Atlantic for help on this definition. House cable owned before divestiture by the Bell System and after divestiture by the Regional Bell Operating Companies will eventually be fully depreciated and will then belong to the customer. See also Binding Post, Block Cable, Block Pair, Feeder Box, House Box, Krone Block, Riser Cable and Terminal Box.

Housekeeping

1. In data processing, an operation contributing nothing to the throughput or output, but is necessary to maintaining operation.

2. In communications, housekeeping is more commonly called "overhead."

3. When technical conferences are held, the lead speaker will often start the conference with "housekeeping" messages. That messages will touch on such important information as where the bathrooms are, when lunch will held, where it will be, where the phones are, what the expected dress for the evening's party is, etc.

4. Housekeeping is a for a communications satellite in orbit , all its support systems and the power they consume ; i.e., everything on board the satellite except for the communications equipment fulfilling its primary purpose.

How Are You Today?

"Mr. Newton, how are you today?" is the question that telemarketers most often open a sales-pitch when they make cold calls, i.e. calling people they've never talked to before. I have many responses, but my favorite is, "Thank you for asking. I've just returned from the bankruptcy court having declared personal bankruptcy as a result of my double amputation which happened when the family car got sideswiped by a truck, killing my wife and two children. Now what can I do for you?" If the telemarketer still tries to sell me something (which some actually do), I hang up and pray they don't call back.

Howler

A device which produces a loud sound to a subscriber's phone or private branch exchange (PBX) extension to indicate that the handset is off-hook and it ought to be put back on hook.

Howler Tone

A tone which gets increasingly louder over a short period of time. It is used to notify a user that his phone handset is off its hook.

Howling

Howling is typically heard in a speakerphone or conferencing unit when there is "Acoustic coupling" between the microphone and the speaker. This is due to putting the microphone too near the speaker. New circuits called acoustic echo cancelers allow you to operate the microphone and the speaker simultaneously and much closer to each other.

HP

Hewlett-Packard Company. HP was formed in 1939 by Bill Hewlett and David Packard. David lost the toss to Bill, which is why the company is called Hewlett-Packard, not Packard-Hewlett. They started the company in a small garage in Addison Avenue in Palo Alto, CA. Their first sale was an audio oscillator used in a Disney film, "Fantasia." See also MBWA.

HP Openview

Hewlett-Packard's Openview network management products allow network administrators to monitor and control network devices from an MS-DOS PC or UNIX workstation.

HPA

1. High Performance Addressing. A passive-matrix LCD display technology that is faster and higher contrast than regular LCD displays. HPA monitors are cheaper to make, and popular with laptop makers looking to build low-cost, high-quality products.

2. See High Power Amplifier.

HPAD

Host Packet Assembler/Disassembler. The HPAD can link to a host or FEP with native protocol data, or if the host can accept it, with X.25 input. The 4400 PAD functions as either an HPAD or a TPAD See TPAD.

HPC

HPCs, or Handheld PCs, are a new category of mobile companion devices for Windows-based PCs based on Microsoft's Windows CE platform. HPCs have been designed to provide the millions of mobile professionals using personal computers running Windows an affordable, easy-to-use mobile PC companion to carry their most important information when they are away from their personal computer. HPCs can access the Internet to send and receive e-mail or browse the Web. The HPC is a mobile PC companion and is designed to complement, not replace, desktop, laptop, and notebook computers. Companion applications developed for the HPC are not intended to replace the functionality of personal computer applications. The HPC is not a PDA, but rather an affordable handheld PC companion. PDAs can generally be classified as stand-alone, keyboardless devices with proprietary user interfaces and applications that require pen-based entry and navigation. See PDA.

HPCC

High-Performance Computing and Communications. U.S. government- funded program advocating advances in computing, communications, and related fields. The HPCC is designed to ensure U.S. leadership in these fields through education, research and development, industry collaboration, and implementation of high-performance technology.

HPFS

High-performance file system (HPFS); primarily used with the OS/2 operating system version 1.2 or later. It supports long filenames but does not provide security. OS/2 can use any file system it wants, thanks to its installable file system (IFS) architecture. Two choices available are the FAT file system, used by MS-DOS, and the High Performance File System (HPFS). You can mix and match each and select one at boot time, thanks to OS/2's Dual Boot option. IBM, which created OS/2, claims HPFS is much more efficient than FAT. It tries to store all files on disk contiguously and uses its own built-in cache. However, HPFS' most notable attribute is the long 254-character file names and case preservation. OS/2 remembers file names as upper and lower case (though it's not case- sensitive to commands).

HPO

High Performance Option. A way of improving equipment transmission characteristics. For instance, the upgrading of a voice-grade line to meet standards for data transmission.

HPT

Host Processing Time.

HRC

See Cable Normal Switch.

HS 601 Satellite

DIRECTV uses two Hughes HS 601 body-stabilized satellites in a geosynchronous orbit at 1018 West Longitude. Each satellite contains 16 120-watt transponders. DIRECTV operates 27 of the 32 licensed DBS frequencies at this central orbit location, while USSB broadcasts on the other 5. Employing circular polarization, the satellites provide coverage over the contiguous United States.

HSA

High-Speed Access.

HSB

Hot StandBy.

HSC

Hierarchical Storage Controller.

HSCSD

High Speed Circuit Switched Data. A wireless term. A pre-third-generation standard (2.5G) for adding faster data transmission to existing GSM networks by upgrading the network software. Data speed is 14,400 bits per second to 57,600 bits per second. HSCSD is circuit switched, not packet, so not a particularly efficient use of network resources.

HSCS

High Speed Circuit Switched.

HSCSD

High Speed Circuit Switched Data. HSCSD has relevance in the existing GSM cellular world, where data communications currently is limited to 9.6 Kbps in support of applications such as e-mail, fax, PC file transfer, and short message service. HSCSD will enable the transmission of data at speeds up to 57.6 Kbps through the concatenation (linking) of as many as four GSM time slots of 14.4 Kbps, each. As GSM provides a circuit-switched, rather than a packet-switched, connection, HSCSD is more suited for connection-oriented applications such as video and multimedia. E-mail and other bursty data communications applications are served more cost-effectively by packet data network protocols. See also GPRS, GSM, and UMTS.

According to Ericsson, "Today's data transfer rate of 9,600 bits per second (supporting fax, e-mail, voice/fax mail, PC file transfer and short message service) will be expanded to 19.2, 28.8, and even 64 kbit/s in the near future. The first step will be to introduce high-speed circuit-switched data (HSCSD) solutions which enable users to access two time slots instead of one ” thus doubling the data capability. The second step will be to introduce bandwidth-on-demand (as a built-in capability of HSCSD). By dynamically allocating up to eight time slots for each single data call (64 kbit/s; the full PCS bandwidth), new services can be offered, such as high-speed multimedia access, videoconferencing and CD- quality sound. With the HSCSD high-speed data capacity, graphics-heavy World Wide Web pages can in principle be downloaded as easily and quickly as via a terrestrial connection. See www.ericsson.se/Review/ According to www.telecoms-mag.com, "GSM already meets many of the requirements for UMTS (Universal Mobile Telecommunications Systems), with the key exception of wideband radio access. However, two new service classes under development for GSM will expand the current user data rate of 9.6 kbps to 100 kbps and beyond: high-speed circuit switched data (HSCSD) and general packet radio service (GPRS). Both techniques are designed to integrate with current GSM infrastructure. HSCSD bearer services up to 64 kbps in GSM using multi-slot transmission have already been demonstrated. This technique bundles up to eight TDMA slots within the 200 kHz GSM carrier to create a higher bandwidth channel. HSCSD is also being developed to provide bandwidth-on-demand at variable data rates.

HSD

1. Home Satellite Dish.

2. High Speed Data. Usually refers to broadband Internet access through a cable modem. Speeds are about 100 times faster than a regular POTS modem.

3. High-Speed Synchronous Data.

HSDA

High Speed Data Access.

HSDL

High-speed Subscriber Data Line. A Bellcore idea for a two pair phone line coming into a house or business that is a full-duplex T-1 line. See also ADSL.

HSDU

High Speed Data Unit.

HSL

A computer imaging term. A color model based on hue, saturation, and luminance. Hue is the attribute that gives a color its name (e.g., red, blue, yellow, or green). In this model, saturation refers to the strength, or purity, of the color. If you mix watercolors, saturation would specify how much pigment you added to a given amount of water. Luminance identifies the brightness of a color . For example, full luminance yields white, while no luminance yields black. See also HSV.

HSLN

High-Speed Local Network. A local network designed to provide high throughput between expensive, high-speed devices, such as mainframes and mass storage devices.

HSPD

High-Speed Packet Data. A term for putting data onto a digital cell phone service, largely CDMA. The latest version of HSPD services transfer packet data at speeds of up to 64 kilobits per second (kbps). The latest version of HSPD includes voice enhancements, full compliance with IS-95B, improved handoff , call setup, roaming indication, incoming call forwarding, neighbor searching and pilot reporting.

HSR

Harmonic Suppression Reactor. A specially designed inductor that is inserted in series between a utility's power factor correction capacitor bank and ground. This "detunes" or breaks up a power line resonant condition (usually at 540 Hz or the 9th harmonic) that is causing telephone line power influence and noise problems.

HSRP

Hot Standby Routing Protocol, a proprietary routing protocol from Cisco for fault- tolerant IP routing. According to Cisco, "HSRP enables a set of routers to work together to present the appearance of a single virtual router or default gateway to the hosts on a LAN. HSRP is particularly useful in environments where critical applications are running and fault- tolerant networks have been designed. By sharing an IP address and a MAC address two or more routers acting as one virtual router are able to seamlessly assume the routing responsibility in the case of a defined event or the unexpected failure. This enables hosts on a LAN to continue to forward IP packets to a consistent IP and MAC address enabling the changeover of devices doing the routing to be transparent to them and their sessions." HSRP performs a function very similar to that of both IP Standby Protocol, a proprietary protocol from DEC, and VRRP (Virtual Router Redundancy Protocol), an IETF standard. See also VRRP.

HSSI

High Speed Serial Interface. A serial data communication interface optimized for high speeds up to 52 Mbps. Used for connecting an ATM switch to a T-3 DSU/CSU, for example.

HSSP

High Speed Switched Port.

HST

High Speed Technology, a U.S. Robotics proprietary signaling scheme, design and error control protocol for high-speed modems. HST incorporates trellis -coded modulation, for greater immunity from variable phone line conditions, and asymmetrical modulation for more efficient use of the phone channel at speeds of 4,800 bps and above. HST also incorporates MNP-compatible error control procedures adapted to asymmetrical modulation.

HSTR

High Speed Token Ring. Proposals have been made (1997) by IBM to the IEEE 802.5 working group for high-speed versions of the Token Ring LAN standard. HSTR proposals specify operating speeds of 100, 128 and 155 Mbps. Current and traditional versions of Token Ring operate at 4 and 16 Mbps, putting Token Ring at a decided disadvantage in comparison to Fast Ethernet and ATM. IBM plans to move forward with product development while the standards process works its magic, i.e. takes its long slow time. See also ATM, Fast Ethernet and Token Ring.

HSV

1. A computer imaging term. A color model based on hue, saturation, and value. Hue specifies the color, as in the HSL model. In this model, saturation specifies the amount of black pigment added to or subtracted from the hue. Value identifies the addition or subtraction of white pigment from the hue.

2. Hosted Software Vendor. Another term for an ASP ” Application Service Provider. See Application Service Provider.

HTCP

HyperText Caching Protocol. A protocol used in the Internet for discovering HTTP caching proxies and cached data. HTCP includes HTTP headers, unlike ICP (Internet Caching Protocol), which are vital to caching proxies. See also Cache, HTTP, ICP, and Proxy.

HTG

Hunt Group.

HTML

HyperText Markup Language. This is the authoring software language used on the Internet's World Wide Web. HTML is used for creating World Wide Web pages. HTML is basically ASCII text surrounded by HTML commands in angle brackets, which your browser interprets whichever way it feels. That means (and I reiterate this) different browsers will display the exact same HTML code differently. Here is an example of a simple line of HTML code:

 <H2>Call Center Magazine Editorial Calendar</H2> 

This line says to the browser: Display those words as a type 2 headline. You can also include an image in an HTML page.

 <img src="photos/harry.gif"> 

Your browser would go find the picture "harry.gif" in the subdirectory called "photos" on the computer which had the URL and the Web page you were visiting. An HTML document has three types of content: tags (which define type styles, like the one above), comments (words to tell the HTML author what he's doing, but which aren't displayed) and text (i.e. the words Call Center Magazine Editorial Calendar. Tags also let you do hyper- linking, which lets a person browsing click your HTML document, click on that hyperlink and go elsewhere ” either to another page which you wrote, or to another Web page (i.e. URL) across the world.

Here's an example of text and tags you might put in your HTML document:

 <h2>For more information on computer telephony, please visit</h2> <a href="http:/www.computertelephony.com"></a> 

When someone browsing your page places their mouse on the words "www.computertelephony.com," their cursor changes to a hand. They click on it. A few seconds later, they see the computer telephony home page begin to download. See HTML 1.0, HTML 2.0, HTML 3.0 and HTML 3.2.

HTML 1.0

This original specification was drafted in 1990. It was designed primarily for publishing scientific papers to the Web. The spec contained features such as six levels of headings, simple character attributes, quotations, source code listings, list, and hyper- links to other documents and images. It is no longer used. See HTML.

HTML 2.0

This revised specification for HTML arrived in 1994. It added forms and eliminated many seldom-used tags from the original spec. It also included support for pop-up and pull-down menus , buttons , and text-entry boxes that could be used for filling in forms. As of this writing (Winter of 1996-97), this is the specification that all products support in full. See HTML.

HTML 3.0

The proposal for this HTML specification was published in 1995. The spec called for the inclusion of coding for tables, text flow around figures, and mathematical equations. The spec was too progressive and garnered only piecemeal product support. It has since been dropped in favor of HTML 3.2. See HTML.

HTML 3.2

This new specification for HTML was developed by vendors that include IBM, Microsoft, Netscape, Novell, SoftQuad, Spyglass, and Sun Microsystems. It proposed the inclusion of support for tables, applets, text flow around images, superscripts, and subscripts. Both Microsoft and Netscape have added extensions to HTML that in some cases have been included in the subsequent standard. Netscape first introduced Java, tables, and frames, and Microsoft introduced ActiveX controls. See HTML.

HTML Editor

Software program that allow one to easily convert text documents to HTML code, without special training or programming skills.

HTML Tag

A symbol used in HTML to identify a page element's type, format, and structure. The FrontPage Editor automatically creates HTML tags to represent each element on the page.

HTR

Hard-To-Reach.

HTTP

HyperText Transfer Protocol. HTTP is the standard way of transferring information across the Internet and the World Wide Web. It supports a variety of media and file formats across a variety of platforms. Invisible to the user, HTTP is the actual protocol used by the Web Server and the Client Browser to communicate over the "wire". In short, the protocol used for moving documents around the Internet. http://www is the standard prefix for the Internet of a site on the world wide web. See Domain, DRP, Internet, Surf, URL, Web Address and Web Browser.

HTTPS

Hypertext Transfer Protocol Secure. A type of server software which provides the ability for "secure" transactions to take place on the World Wide Web. If a Web site is running off a HTTPS server you can type in HTTPS instead of HTTP in the URL section of your browser to enter into the "secured mode". Windows NT HTTPS and Netscape Commerce server software support this protocol.

Hub

The point on a network where circuits are connected. In local area networks, a hub is the core of a physical star configuration, as in ARCNET, StarLAN, Ethernet, and Token Ring. Hub hardware can be either active or passive. Wiring hubs are useful for their centralized management capabilities and for their ability to isolate nodes from disruption. Hubs work at Layers 1 (Physical) and 2 (Data Link) of the OSI Reference Model, with emphasis on Layer 1. Hubs aren't switches, as they have very little intelligence, if any, and don't set up transmission paths. Rather, hubs comprise a physical bus and a bunch of ports, to which are connected a bunch of wires, to which are connected individual terminal devices. As hubs are protocol-specific (e.g., Ethernet) and are not intelligent, they are very fast and very cheap. 10Base-T and 100Base-T, for instance, are Ethernet hub technologies. The 10/100Base-T hub is an inexpensive means of allowing LAN-attached devices to share a common, collapsed bus contained within a hub chassis. The connections are via UTP (Unshielded Twisted Pair), which is much less expensive than are the classic connections through coaxial cable. Unlike switches, hubs do nothing internally to control congestion. However, they typically are workgroup-level solutions which allow a large, logical Ethernet to be subdivided into multiple physical segments. For example, you could even use a small five-port hub on your desk to connect a couple of laptops and a desktop PC. Hubs can be interconnected directly, or through switches or routers, with the traffic being forwarded from the originating hub only if the destination address of the data packet indicates that it is necessary to do so. Therefore, hubs do reduce congestion through the control of interhub traffic. See also 10Base-T, Ethernet, Router and Switch.

HUB Expansion Port

An older local area network term for two ports located to the right of a 2008, 2016 or 2116 repeater used to interconnect these repeaters in a stack. The interconnect cable is standard Category 5 UTP cable. These ports are now called Repeater Expansion Ports (REP).

Hub Junction Box

A box used to connect a hub interface when a node is placed at a remote location.

Hub Management Interface

A network management protocol developed by Novell to allow network managers to manage hubs anywhere on a NetWare LAN.

Hub Polling

A polling system in which a polled station sends its traffic and passes the polling message (after it's sent its message) to the next station.

Hub Site

The location(s) on a network where many circuits are brought together to be multiplexed into a single higher speed connection.

Hubble, Edwin P.

American astronomer , (1889 - 1953), whose observations proved that galaxies are "island universes", not nebulae inside our own galaxy. His greatest discovery, called "Hubble's Law", was the linear relationship between a galaxy's distance and the speed with which it is moving. The Hubble Space Telescope is named in his honor .

Hublet

A mini-hub, submitted by Tracy Meyer, Network Technician, Pacific Bell Mobile Services. The term was created by Mark Alexander an Engineer at Pacific Bell Mobile Services who came up with it. "It is growing in popularity here," according to Tracy.

Huddle

The "huddle" in football originated because of a deaf player who used sign language to communicate, and his team did not want the opposition to see the signals he used so they huddled around him.

Huddle Spaces

Areas such as cybercafes, which are designed for informal meetings, change encounters and work breaks to foster idea exchange and communications.

Hue

The attribute by which a color may be identified within the visible spectrum. Hue refers to the spectral colors of red, orange, yellow, green, blue and violet .

Huffman Coding

Developed by D.A. Huffman, a popular lossless data compression algorithm that creates shorter, variable-length codewords for input symbols, i.e., the letters that comprise a phrase. Huffman Coding replaces frequently occurring characters and data strings with shorter codes. For example, Huffman Coding examines the string of symbols that comprise a phrase. The symbols then are ranked according to the frequency of their occurrence, in a top-down approach. (Shannon-Fano Coding is similar, although it is a bottom-up approach that generally is considered to be less efficient.) The two symbols with the lowest probabilities are represented by one new, composite symbol with an assigned probability equal to the sum of the probabilities of the two symbols. This process continues successively up the probability rank, building a binary tree, with each node or branch being the probability of all nodes or branches beneath it. A path can be followed to an individual leaf, which is in the form of a compressed representation of an individual letter of an alphabet. Dynamic Huffman Coding reads the information twice, the first time to determine the frequency with which each data character appears in the text and the second time to accomplish the actual encoding process. Huffman Coding suffers from the fact that it does not recognize characters between 0 and 1; for instance, 4.6 would be rounded to either 4 or 5. Huffman encoding is often used in image compression. It also is used in PKZIP, along with other compression algorithms. Modified Huffman (MH) is used in many fax machines, although it supports relatively slow transmission at 9.6 Kbps, or about 30 seconds per page. See also Compression and Shannon-Fano Coding.

Huge Pipes

From Wired's Jargon Watch column. A high-bandwidth Internet connection. "CU-SeeMe doesn't look half-bad ” if you've got huge pipes."

Hum

1. Hum on phone lines sounds awful and can severely cut your data throughput. Hum on a phone line may have many sources ” grounded carbon, lightning-damaged protection, left in drops or jumpers , "half-tap," or a wet cable. A wet cable pair "usually" manifests itself with a "frying" sound or crosstalk with other pairs. The solution to hum on the line is to replace the pair or remove the offending section of the pair from your circuit.

2. Noise that is present in some communications equipment, hum usually is induced either by coupling to a 60-cycle electrical source or defective filtering of 120-cycle output of a rectifier . See Hum Bucket.

Hum Bucker

A circuit (often a coil) that introduces a small amount of voltage at power line frequency into the video path to cancel unwanted AC hum.

Hum Modulation

Noise which unintentionally modulates a desired signal.

Human Resource Forensics

The idea is to check that your employees aren't doing anything that might harm your company. So now there's a growing band of specialists in a field called human-resource forensics. These guys are using the latest technology to record everything from the Web sites employees visit to the files they delete to the data they download. There are obvious privacy and morale issues here. Though some forms of surveillance are perfectly proper, using technology to spy on employees can damage workplace morale and, if taken to extremes, test the boundaries of what is ethical or legal. These people (also called "experts") urge companies to think hard before turning their workplaces into areas where no one feels trusted.

Humidification

The process of adding moisture to the air within a critical space. Without humidity, you get static electricity. With static electricity comes strong shocks to computers equipment. With strong shocks comes loss of data. Lack of humidity is particularly bad in the middle of winter.

Humint

Humint stands for human intelligence, as contrasted to sigint, which is signals intelligence.

Hundred Call Seconds

Known by the initials CCS where C is the roman numeral for Hundred. One CCS is 36 times the traffic expressed in Erlangs. See CCS.

Hunt

Refers to the progress of a call reaching a group of lines. The call will try the first line of the group. If that line is busy, it will try the second line, then it will hunt to the third, etc. See also Hunt Group.

Hunt Group

A series of telephone lines organized in such a way that if the first line is busy the next line is hunted and so on until a free line is found. Often this arrangement is used on a group of incoming lines. Hunt groups may start with one trunk and hunt downwards. They may start randomly and hunt in clockwise circles. They may start randomly and hunt in counter-clockwise circles. Inter-Tel uses the terms "Linear, Distributed and Terminal" to refer to different types of hunt groups. In data communications, a hunt group is a set of links which provides a common resource and which is assigned a single hunt group designation. A user requesting that designation may then be connected to any member of the hunt group. Hunt group members may also receive calls by station address. See also Terminal Hunt Group.

Hunt group helpers

Most intelligent businesses run their faxes in hunt groups. Five fax machines in a hunt group can process as many calls as 45 faxes on individual lines. The problem with hunt groups is that when the first fax machine runs out of paper, it typically won't answer the phone. This means calls won't roll over. They just keep landing on the "sleeping" fax machine. A hunt-group helper, which is a piece of hardware installed before the fax machine ” between it and the central office phone line ” listens to the number of rings on each line of a hunt-group set and rolls the call over to the next line if a given machine lets the line ring too many times (i.e. it's probably out of paper). A simple fix, works great.

Hunting

See Rollover Lines.

HUT

1. High Usage Trunk.

2. Telecommunications equipment that house loop concentrators or multiplexer, a housing device.

HVAC

Heating, Ventilating, and Air-Conditioning systems. High voltage stuff. Keep your telecommunications cables away from the motors in HVAC systems, please.

HVQ

Hierarchical Vector Quantization ” a method of video compression introduced by PictureTel in 1988 which reduced the bandwidth necessary to transmit acceptable color video picture quality to 112 Kbps.

HW

Email abbreviation for hardware.

Hybrid

A device used for converting a conversation coming in on two pairs (one pair for each direction of the conversation) onto one pair and vice versa. This is necessary because all long distance circuits are two pairs, while most local circuits are one pair. Here is a longer explanation from "Signals, The Science of Telecommunications," by John Pierce and Mike Noll:

The telephone instrument in your home is connected to a single pair of wires called the subscriber loop or local loop, which carries both the outgoing voice signal and the incoming one. This pair of wires creates an electrical circuit for each of the two signals. A device in your phone called a hybrid or hybrid coil keeps the two signals separate, more or less, so that what you say into your phone's transmitter doesn't blast into your ear from the receiver.

In contrast, all multiplex systems provide separate talking paths in two directions. Separate paths are necessary because the amplifiers placed along the lines between terminals amplify signals traveling in one direction only. When two people talk between New York and San Francisco the call goes from one phone through a local two-wire voice circuit to a multiplex terminal. There the call is transferred to a four-wire long distance circuit that consists of two separate one-way circuits. At the end of the system, a hybrid reconverts each four-wire circuit into a two-wire circuit.

Hybrid Backbone

Two or more types of facilities in a corporate telecom WAN ” e.g. ATM and SONET.

Hybrid Cable

A communication cable that contains two or more types of conductors that bear electrical signals, a mixture of signal-bearing electrical conductors and optical fibers, and/or two or more different types of optical fibers. A communication cable containing signal- bearing media and electric power conductors.

Hybrid CDPD

Circuit-switched CDPD (Cellular Digital Packet Data), a technology known as hybrid CDPD, is the system architecture developed by the CDPD Forum for interconnecting circuit-switched data, including cellular and land-line, with the CDPD network.

Hybrid Coil

A transformer-like device which is designed to provide the interface between a two-wire and a four-wire circuit. The device has four ports designed such that a signal input to one port will be split evenly to two adjacent ports, with no signal coupled to the opposite port. One port is connected to the two-wire line. The two adjacent ports are connected to the four-wire line. The opposite port is connected to a balance network to cancel any stray signals. See Hybrid for a longer explanation.

Hybrid Communication Network

A communication system that uses a combination of trunks, loops, or links, some of which are capable of transmitting (and receiving) only analog or quasi-analog signals and some of which are capable of transmitting (and receiving) only digital signals.

Hybrid Connector

A connector containing both optical fiber and electrical conductors.

Hybrid Coupler

In antenna work, a hybrid junction forming a directional coupler. The coupling factor is normally 3 dB.

Hybrid Disk

1. A CD-ROM term. Under the Orange Book standard for recordable CD, a hybrid disc is a recordable disc on which one or more sessions are already recorded, but the disc is not closed, leaving space open for future recording. However, in popular use the term "hybrid" often refers to a disc containing both DOS/Windows platform is seen as a ISO 9660 disc, while on a Mac it appears as an HFS disc.

2. A CD-ROM disc which works in both a Macintosh and an MS-DOS/Windows. Most these days do.

Hybrid Fiber/Coax (HFC)

At its simplest, Hybrid Fiber/Coax describes any network architecture for cable or telephone networks which employs some combination of fiber and coaxial cable. But the term "Hybrid Fiber/Coax" also describes a specific network architecture employed by most cable operators and some telephone companies. This HFC architecture is an evolution of the traditional cable distribution network, which employed a bus from the cable operator's headend, down each street, with taps outside each subscriber's home. When the cable from the headend is fiber, and an optical-to-electrical conversion is performed to place the signal on coax before we reach the subscriber's tap, that network is described as a Hybrid Fiber/Coax bus.

Hybrid Firewall

A network protection device that includes various firewalling features (e.g. packet filtering, circuit-level proxies, application-level proxies, etc.) in order to guard against multiple forms of attack.

Hybrid Integrated Circuits

The combination of thin-film or thick-film circuitry deposited on substrates with chip transistors , capacitors and other components. Thin-film construction is used for microwave integrated circuits (MICs).

Hybrid Junction

A waveguide or transmission line arrangement having four ports that, when terminated in their characteristic impedance, have the property that energy entering any one port is transferred (usually equally) to two of the remaining three ports. Widely used as a mixing or dividing device.

Hybrid Key System

Term used to describe a system which has attributes of both Key Telephone Systems and PBXs. The one distinguishing feature these days is that a hybrid key system can use normal single line phones in addition to the normal electronic key phones. A single line phone behind a hybrid works very much like a single line phone behind a PBX. The second distinguishing feature of a hybrid is that it's "non-squared." This means that not every trunk appears as a button on every phone in the system ” as occurs on virtually every electronic key system manufactured today.

Hybrid Local Network

An integrated local network consisting of more than one type of local network (e.g. LAN, HSLN, digital PBX).

Hybrid Mode

A mode possessing components of both electrical and magnetic field vectors in the direction of propagation.

Hybrid Network

1. A communications network which has some links capable of sending and receiving only analog signals and other links capable of handling only digital signals. The current public switched telephone network is Hybrid. A Hybrid Network is also a network with a combination of dissimilar network services, such as frame relay, private lines and/or X.25.

2. An amalgam of public and private network transmission facilities.

Hybrid Satellite

A satellite that carries two or more different communications pay- loads (i.e., C-band and Ku-band).

Hybrid Set

Two or more transformers interconnected to form a network having four pairs of accessible terminals to which may be connected four impedances so that the branches containing them may be made interchangeable.

Hydra

A 25-pair cable that at one end has an Amphenol connector (typical of what 1A2 phone systems were connected with) and at the other has many individual 2, 4, 6 and 8 wire connectors, typically male RJ-11s. A hydra cable is named for a mythological multi- headed monster. It's more commonly called an octopus cable. The reason it's called an octopus is that it looks a bit like an octopus ” one body and many arms.

Hydrogen Loss

Increases in optical fiber attenuation that occur when hydrogen diffuses into the glass matrix and absorbs some light.

Hydrometer

Instrument for determining the density of liquids. Formerly in wide use for testing radio storage "A" batteries.

Hygroscopic

Capable of absorbing moisture from the air.

Hyperband

A cellular wireless term meaning the ability of a radio to handle calls originating in different frequencies. On Feb. 10, 1997, Ericsson conducted the first public hyperband hand-off between the 1900 MHz and 850 MHz systems at the Universal Wireless Communications (UWC) conference in Orlando. The hyperband call, which used the TDMA IS- 136 digital wireless technology, was connected and carried across the United States through AT&T Wireless Services' network in five cities. This demonstrates the ability for operators to establish networks in either band, and connect them in a multi-vendor environment, enabling nationwide and international roaming. Advanced digital wireless applications deploying public and private networks were demonstrated including: Location and Caller ID, Short Message, Message Waiting Indicator, Voice Mail, four digit extension dialing and intelligent roaming. These advanced capabilities were demonstrated using Ericsson's 1900/850 MHz dual-band phones. These phones are equipped with the new Enhanced Full Rate ACELP vocoder delivering enhanced digital voice quality.

Hypercard

The first desktop program that allowed hypertext creation. It ran on the Mac. Not long after its introduction, Hypercard "stacks" became available, especially in the artistic and educational communities. Stacks are a collection of documents within one package through which the user can jump using hypertext links. Stacks were often made available free through online services.

Hyperchannel

An SCSA term. A data path on the SCbus or SCxbus Data Bus made up of more than one time slot. By bundling time slots into a hyperchannel, data paths with a bandwidth greater than 64 Kbps can be created.

Hyperdata Networking

Hyperdata networking is expanding the capabilities of the LAN from simple data transfer to the delivery of complex applications through the network to the end user. I think this definition is a "stretch," but Richard Herod claims it's for real.

Hyperfiction

According to the New York Times, hyperfiction is a new narrative art form, readable only on the computer, and made possible by the developing technology of hypertext and hypermedia. Not all adults have familiarized themselves with hypertext, but most children have, for it is the basis of many of their computer games and is fast becoming the dominant pedagogical tool of our digitalized times. See Hypertext.

Hyperlink

A link from one part of a page on the Internet to another page, either on the same site or a distant site. For example, a restaurant's home page may have a hyper- link or link to its menu. A retailer of laptops might have a link to the site of the laptop's manufacturer. A hyperlink is a way to connect two Internet resources via a simple word or phrase on which a user can click to start the connection. A user can access a Web site and exercise the option to hyperlink to another, related Web site by clicking on that option. You'll recognize hyperlinks on Web pages because the links look different. Typically they're in blue and underlined . Sometimes, you'll see a button saying "For more," "Full specs ," or "Our biography," etc. During the linking process, the user remains connected in a Web session through a process known as spoofing. A hyperlink is also called an anchor.

Hypermedia

A way of delivering information that provides multiple connected pathways through a body of information. Hypermedia allows the user to jump easily from one topic to related or supplementary material found in various forms, such as text, graphics, audio or video.

Another definition we found is: Non-linear media, of which multimedia can be a form. Just as hypertext is a non-sequential, random-access arrangement of text, hypermedia is a non-sequential, random-access arrangement of multiple media such as video, sound and computer data.

A third definition: Hypermedia is a type of authoring and playback software through which you can access multiple layers of multimedia information related to a specific topic. The information can be in the form of text, graphics, images, audio, or video. For example, suppose you received a hypermedia document about the Sun file system. You could click on a hotspot (such as the words file system) and then read a description. You could then click an icon to see an illustration of a file structure, and then click the file icon to see and hear information in a video explaining the file system.

Hyperpartnering

Also known as any-to-any (A2A) collaborative commerce. Designed to help companies jump on B2B market opportunities as they appear. For example, when a distributor reports a sudden surge in demand for a product, a manufacturer could almost simultaneously forge a partnership needed to double the supply of raw materials necessary to produce the product.

Hyperspectral Imaging

Hyperspectral is a new form of imaging much in vogue in space weaponry and space technology. Hyperspectral cameras can take a picture of an ecosystem and discern conifer from deciduous trees. Hyperspectral imaging distinguishes subtle "light signatures" that separate a field of oats from barley and tell you the precise species of oats. And then, according to the New York Times, whether the field is infested with insects or damaged by nitrogen depletion. But the ultimate idea of hyper- spectal imaging is to be able to tell if tanks are sitting under trees, or tanks are covered with camouflage or tanks pained with a paint meant to make them not look like tanks. In short, by mounting hyperspectral cameras on satellite, you are able to tell very precisely what's on the battlefield that might harm you.

Hypertext

The term "hypertext" was coined by Theodore (Ted) Holm Nelson. His middle name comes from his mother, actress Celeste Holm. He developed the concept of hypertext in a paper delivered to the Association for Computing Machinery at its national conference in 1965. Nelson envisioned a nonsequential writing tool which included a feature he called "zippered lists," which allowed textual elements in documents to be linked. We currently associate "hypertext" with the World Wide Web and the HTML language. Imagine you're reading something. You come to a word that's in a different color or perhaps is underlined. You click on the word with your mouse. Suddenly you're transported to another sentence, to another paragraph, to another section somewhere else. That new sentence , paragraph or section may explain the original word. It may take you to another thought. It may take you to another part of the story. The New York Times defines Hypertext as "nonsequential writing made up of text blocks that can be linked by the readers in multiple ways." Hypertext is not only the words and the links. It's also the software that allows users to explore and create their own paths through written, visual, and audio information. Capabilities include being able to jump from topic to topic at any time and follow cross-references easily. Hypertext is often used for Help files. It's being used for "hyperfiction," a new narrative art form, readable only on the computer, made possible by the developing technology of hypertext and hypermedia. See HTTP and Hypertext Transfer Protocol.

HyperText Caching Protocol

See HTCP.

Hypertext Transfer Protocol

HTTP is the transport protocol in transmitting hypertext documents around the Internet. See Hypertext.

Hyperthreading

Hyperthreading is a new technology from Intel which allows a single physical microprocessor to execute two separate code streams (called threads) concurrently. Architecturally, each 1A-32 processor with hyperthreading consists of two logical processors, each of which has its own 1A-32 architecture. After power up and initialization, each logical processor can be halted, interrupted or directed to execute a specified thread. See Thread.

Hyperware

New hardware that has been announced and perhaps even publicly demonstrated, but is not being shipped to commercial customers. Vaporware is software which has been announced, but is not yet shipping to commercial customers. Years can pass between public announcement and actual commercial shipment. Be wary.

Hysteresis

In pure physics, hysteresis is the lag in response exhibited by a body in reacting to changes in the forces, esp. magnetic forces, affecting it. In our industry it has come to acquire a couple of meanings. See also Hysteresis Loss.

1. Hysteresis is an uninterruptible power supply (UPS) definition. The voltage output from the wall will continually shift within a certain range, causing some UPSs to constantly switch back and forth from AC to battery power.

2. Hysteresis is also a buffering approach used in digital cellular networks to prevent the "ping pong" effect which occurs when a telephone repeatedly reselects two cell sites of approximately equal strength. Here's a explanation: The retardation of the accomplishment of a process caused by changing values, especially relating to the lagging of values of resulting magnetization in a magnetic material (e.g., iron) due to a changing magnetic force. From the Greek "hysterisis," translating as "shortcoming." In a physical system, hysterisis is dependent on history. For example, you can push on something, like a sponge, or you can bend something, like a piece of metal. The object doesn't spring back to its exact original form. It remembers its previous position. In other words, the shape of sponge and the piece of metal each depend on their history. In cellular radio terminology, hysterisis is a buffer area, or offset, that prevents a cell phone from bouncing back and forth between two cell sites with roughly equal levels of signal strength. Such a process of repeated reselection causes the "ping-pong" effect that can be so aggravating in digital cellular networks.

Hysteresis loss

A physics term. The loss of energy by conversion to heat in a system exhibiting hysteresis.

Hytelnet

A hypertext system which contains information about the Internet, such as accessible library catalogs, Freenets, Gophers, bulletin boards , etc.

Hz

See Hertz.