HEC-Home Run Cabling


Header Error Control - a CRC code located in the last byte of an ATM (Asynchronous Transfer Mode) cell header used for checking integrity only. Using the fifth octet in the ATM cell header, ATM equipment may check for an error and correct the contents of the header. The check character is calculated using a CRC algorithm allowing a single bit error in the header to be corrected or multiple errors to be detected .

Hedge Fund

A hedge fund is a pool of monies from rich people managed by an investment "professional" that uses more aggressive investment strategies than mutual funds. Such aggressive strategies include: the hedge can sell short, can use leverage and can buy or sell derivatives (like options, futures , etc.), Only " accredited investors" may invest in hedge funds. Such investors are high net worth individuals and institutions who allegedly know what they're doing and don't need the protection and regulation of government entities ” in contrast to mutual funds which are regulated and are typically not allowed to sell short or do other risky strategies ” unless specifically set up for that purpose. Hedge funds are basically not regulated by any government agency.


Head-End Hop Off. You have a private network. You overflow a long distance call to WATS or DDD at the originating end (the end the call is coming from). This HEHO (Head- End Hop Off) is done because it's usually cheaper than carrying the call part way through the network, then jumping off the network at that point (because the network is busy or it won't reach the end point). The opposite of HEHO is TEHO ” Tail-End Hop Off. In TEHO, you carry the call as far as possible through the network, then pass it off to WATS or DDD as close to its destination as possible. The decision to go HEHO or TEHO has to do with economics, primarily which is cheaper.


A young cow. A motorist was killed near Vacaville Calif., in March 1999, when an airborne cow smashed through the windshield of his pickup truck. According to the California Highway Patrol, the 700- pound heifer wandered onto a road during stormy weather, and a 1983 Mercedes Benz traveling north on the road hit it, sending it hurtling through the air into the path of the pickup, which was traveling south. The cow smashed through the windshield, killing the driver. After hitting the pickup, the heifer was batted back onto the southbound lane where it was hit by another pickup. "Vacaville" means "Cow Town" in Spanish.

Hierarchical Routing

Routing based on a hierarchical addressing system. IP routing algorithms use IP addresses, for example, which contain network numbers, host numbers, and frequently, subnet numbers .

Heisenberg's Realization

The mere act of observing affects what is being observed .

Held Call

A held call is a call to which you are connected but which is on hold.

Held Orders

A telephone company term for requests for telephone lines which the phone company cannot fill. Thus it is "holding" the orders. The reasons for holding customer orders might range from lack of capacity at the serving central office to a lack of local cable plant.

Helical Antenna

An antenna that has the form of a helix. When the helix circumference is much smaller than one wavelength, the antenna radiates at right angles to the axis of the helix. When the helix circumference is one wavelength, maximum radiation is along the helix axis.

Helical Scan

Storage method that increases media capacity by laying data out in diagonal strips . Used in video tape recorders , etc.

Helical Strand

A process of twisting conductors of a cable together in a helix, or spiral fashion, in order to improve the break strength of the conductors. See Helix, Stranded Copper and Stranded Fiber.

Helical Stripe

A continuous, colored, spiral stripe applied over the outer perimeter of an insulated conductor for circuit identification purposes.


A spiral. The shape of screw.


When the phone was first invented, no one was sure how to begin the conversation. Thomas Edison saw the telephone as being used by businesses with permanently open lines. How would anyone know that the other party wanted to speak? A letter was found from Thomas Edison, dated August 15, 1877 to the president of the Central District and Printing Telegraph Co. in Pittsburgh. "Friend David, I don't think we need a call bell, as Hello! can be heard 10 to 20 feet away. What do you think, Edison?" At that time Alexander Graham Bell insisted on answering the telephone with "Ahoy." Hello! became the standard as the first telephone exchanges were set up across the country. Hello first appeared in the Oxford English Dictionary in 1883. In September of 1880, the first National Convention of Telephone Companies was held in Niagara Falls. "Hello" was used on everyone's name tag for the first time. Besides electricity, the phonograph and hundreds of other inventions , we can thank Edison for the "Hello" greeting. The above from New Pueblo Communications in Tucson, AZ.

Hello Packet

A type of PNNI Routing packet that is exchanged between neighboring logical nodes.

Help Desk

A centralized location where queries about product usage, installation, problems or services are answered . Sometimes help-desks are provided by the manufacturer of the product. Sometimes help desks are provided by outside companies ” systems integrators, independent software developers and third party companies.

Helper Applications

Programs that can be linked to various file types and commands. Helper apps will launch automatically when linked files are accessed through a browser.


The inductance in a circuit in which the electromotive force induced is one volt when the inducing current varies at the rate of one ampere per second. It is 1,000,000.000 electromagnetic units, and is the unit of inductance.


High Efficiency Particulate Arrester. These high-efficiency, high-priced vacuum cleaner filters are now becoming standard equipment on some electronic and telecommunications hardware. Hepa filters were first used when they performed atmospheric testing of nuclear warheads. They used HEPA filters in the fallout shelters because the degree of filtration was so fine that it could trap radioactive particles, due to the honeycomb design. HEPA files were later used in in medical environments, soon followed by home air filtration. Finally, they are being used in vacuum cleaners. They are not cheap, but do work well, as any person allergic to dust will tell you. Trouble is, it is not clear how often they need to be replaced , unless it looks sort of obvious.


An Internet term. A non-USENET set of newsgroups devoted to discussing the topic of high-energy nuclear physics.


High Energy Radio Frequency gun. Shoots a high- powered radio signal at an electronic target (such as a computer) and puts it out of commission.

Hercules Graphics

Hercules graphics adheres to the Hercules standard of monochrome graphics on a monochrome PC monitor. That standard is 720 x 348 pixel resolution and 64K screen memory. This encoding was never adopted as a color standard and is now pretty well obsolete. See also Monitor and Facsimile.

HERF gun

A High Energy Radio Frequency gun capable of destroying magnetic data storage.

Hermaphroditic connector

A loopback or self-shorting connector typically used with Type 1 (STP) Token Ring cable.

Hermaticity Test

A fine and gross leak test of a hermetically sealed IC to see if there are any leaks in the seal. The gross leak test uses a fluorocarbon fluid, and the fine leak test uses a light gas such as helium.

Hermetic Coating

A coating applied over the cladding of a fiber that retards the permeation of moisture and hydrogen into the fiber.

Hero Experiment

An experiment that attempts to push the capabilities of a technology to its limits. It is used most often to refer to experiments that set world records for transmission distance and/or rate of speed. The experiment itself often has no immediate commercial value but does provide valuable, basic research that may prove valuable over the longer term.


The game called Doom played on corporate networks in often called Heroinware, because the game is so addictive .


Moving or stationary lines superimposed on a television picture.


Abbreviated Hz. A measurement of frequency in cycles per second. A hertz is one cycle per second, and is the basic measurement for bandwidth in analog terms. "Hertz" is named after Heinrich Rudolf Hertz, the physicist who discovered the presence of electromagnetic radio waves. Cats purr at 26 cycles per second, the same as an idling diesel engine. Electricity cycles at 50 or 60 times per second. See Analog and PCM.

Hertz, Heinrich

A German physics professor , (1857 - 1894), who did the first experiments with generating and receiving electromagnetic waves, in particular radio waves. In his honor , the units associated with measuring the cycles per second of the waves (or the number of times the tip-tops of the waves pass a fixed point in space in 1 second of time) is called the hertz. See Hertz.

Hertzian Wave

A name sometimes given to electromagnetic waves.


The Greek prefix meaning different.


To generate new frequencies by mixing two or more signals in a nonlinear device such as a vacuum tube, transistor , or diode mixer. A superheterodyne receiver converts any selected incoming frequency by heterodyne action to a common intermediate frequency where amplification and selectivity (filtering) are provided. A frequency produced by mixing two or more signals in a nonlinear device. See Heterodyning.

Heterodyne Channel Converter

A converter which uses heterodyne principles to down convert signals on one channel and then re-convert the signals to a new channel. Generally heterodyne converters produce higher quality results than those which use frequency multiplication principles. Occasionally the program may be demodulated to a base band frequency (in order to interface with the base band encryption equipment) and then re-modulated. Converters often have amplifiers , filters, or demodulators, and modulators to "boost" and "clean-up" signals. See Channel Converter, Converter, Heterodyne and Heterodyne Converter.

Heterodyne Converter

A device consisting of an oscillator and a mixer which beats two signals together for the purpose of down converting or up-converting a modulated carrier.

Heterodyne Repeater

A repeater for a radio system in which the received signals are converted to an intermediate frequency, amplified, and reconverted to a new frequency band for transmission over the next repeater section.


Here is an explanation from James Harry Green's book, the Dow Jones Handbook of Telecommunications: Analog microwave repeaters use either of two techniques to amplify the received signal for retransmission: Heterodyning or Baseband. In a baseband repeater, the signal is demodulated to the multiplex (or video) signal at every repeater point. In heterodyne repeaters the signal is demodulated to an intermediate frequency, typically 70 MHz, and modulated or heterodyned to the transmitter output frequency. Heterodyne radio is reduced to baseband only at main repeater stations where the baseband signal is required to drop off voice channels. The primary advantage of baseband radio is that some carrier channel groups can be dropped off at repeater stations . Heterodyne radio has the advantage of avoiding the distortions caused by multiple modulation/demodulation and amplification of a baseband signal. Therefore, heterodyne radio is employed for transcontinental use with drop-off points only at major junctions.

Heterogeneous Networks

Networks composed of hardware and software from multiple vendors usually implementing multiple protocols.


A junction between semiconductors that differ in their doping level conductivities, and also in their atomic or alloy compositions.


Using much trial and error to arrive at a solution to a problem.


Abbreviated as Hex. "Hex" is from the Greek "hex," meaning "six." "Decimal" is from the Latin "decem," meaning "ten." Hexadecimal is a numbering system of 16 characters , ten digits and six letters . It is used to condense the long strings of zeros and ones in large binary numbers. This base-16 numeric notation system is frequently used to specify addresses in computer memory. As a sort of programming shorthand, hex makes life simpler for programmers by allowing eight-bit binary values, or bytes, to be expressed with only two hexadecimal characters (though, obviously longer numbers do have more hexadecimal characters). In hexadecimal notation, the decimal numbers 0 through 15 are represented by the decimal digits 0 through 9 and the alphabet "digits" A through F (A=decimal 10, B=decimal 11, and so forth). For example, a binary (base 2) "11111111" equates to a decimal (base 10) 255, and is expressed as "FF" in hex (base 16). There are many conventions for distinguishing hexadecimal numbers from decimal or other bases in software. In C for example, the prefix "0x" is used, e.g. 0x694A11. In Web design, hexadecimal is the alphanumeric system used to specify colors in HTML. For example, the hexadecimal equivalent of white is FFFFFF, while black is 000000. See also Byte and Nibble.


  1. Hands Free.

  2. High Frequency. Portion of the electromagnetic spectrum, typically used in short- wave radio applications; frequencies approximately in the 3MHz to 30 MHz range.


Hands Free Answer on Intercom. A desirable feature of several phone systems.


Hybrid Fiber Coax. An outside plant distribution cabling concept employing both fiber optic and coaxial cable. Fiber is deployed as the backbone distribution medium, terminating in a remote unit where optoelectric conversion takes place. At that remote unit, the signal then is passed on to coax cables which carry the data the last leg to the individual business, residence, dormitory room, etc. HFC systems provide substantial bandwidth at lower cost than a system based exclusively on fiber. Given the embedded base of coaxial cable in college and university campuses, HFC is an effective means of delivering combined voice, data, video and CATV to dormitory rooms and classrooms. HFC also is used extensively in upgraded CATV networks for the same reasons. See also FSAN.


Hands Free Unit.


Home Gateway. A device located on a corporate LAN that accepts authorized user tunnels over the Internet.


Hercules Graphic Card; long the standard monochrome graphics adapter for PCs and compatibles, now well and truly obsolete. Maximum resolution is 720 x 348 pixels.


High Capacity. These facilities are defined as special access circuits that fall into certain specific classes of service.

Hi-Lo Tariff

A long distance private line tariff filed by AT&T whereby private lines between major cities were priced lower than private lines between smaller cities. In effect, those "larger" cities were those MCI operated in and those "smaller" cities were those MCI didn't operate it. Eventually the tariff was thrown out by the FCC and it figured in anti-trust suits by MCI and the Federal Government against AT&T.

HI8 Video

The high-quality extension of the Video 8 (or 8mm) format, which features higher luminance resolution.


The concept is simple. You turn your computer off in the middle of a program. It goes to sleep. When you turn it on, it returns to exactly where you left it, without the need for rebooting. These days most laptops have some form of hibernation or suspend software. There are basically two methods . First, "Suspend" makes a copy the entire contents your RAM memory and what files you have open at that time. It dumps that information into RAM memory and keeps that memory alive with a special battery inside your laptop. Most laptops have three batteries ” a big one that you can change, a small one for suspend and a third one for running the clock. When you plug your laptop into AC, it charges all three batteries. Suspend will last as long as there's charge in the battery keeping your RAM memory alive . That's typically a day. Second, "hibernation" is the same concept except that it writes the RAM's contents to a special part of your hard disk. When you start your computer next time, "hibernation" tells it to read that part first. Hibernation can last as long as 45 days. Hibernation is scarey because if your computer messes up and can't find that precious file, it screws up. Your computer might be able not start a normal Windows boot and your computer may never start. My computer technician tells me never to use "hibernation." Suspend, he says, is fine. The reason I include this definition is that you cannot use suspend or hibernation if your laptop is attached to a network. It simply won't work. If you're attached to a network, the best routine is to leave your machine on permanently or close it down completely, i.e. by turning off the power.

Hidden Markov Method

HMM. A common algorithm in voice recognition which uses probabilistic techniques for recognizing discrete and continuous speech.

Hierarchal File System

A system of arranging files in directories and subdirectories to maintain hierarchical relationships (one file ranked above the other) between the files and make them easier to find and retrieve. See Relationship Database.

Hierarchical Network

  1. A network that includes two or more different classes of switching systems in a defined homing arrangement, meaning to home in on the telephone you wish to be connected to. This is a fancy Bell System (Oops, I mean AT&T - Old habits die hard) term meaning that when direct circuits between two switches are busy or too far apart to be directly connected, the machinery will seek a higher level of switches to route the call through.

  2. A LAN (Local Area Network) term describing a network employing OSI Layer 3 routers. Flat networks, on the other hand, make use of Layer 2 bridges, hubs and switches for LAN interconnection and segmentation. Routers make intelligent decisions about routing data packets, with such decisions taking into consideration the condition of the entire network; Layer 2 devices forward packets on a link basis. Hierarchical router networks are more complex and expensive, and are slower. However, they also can add value through protocol conversion and flow control. Routers, by the way, typically serve to interconnect bridges, hubs and switches, as well as to provide access to the WAN (Wide Area Network). See also Flat Network, Bridge, Hub, Switch and Router.

Hierarchical Routing

The process of establishing a network data path to a destination based on addresses with some kind of ranking criteria.

Hierarchically Complete Source Route

An ATM term. A stack of DTLs representing a route across a PNNI routing domain such that a DTL is included for each hierarchical level between and including the current level and the lowest visible level in which the source and destination are reachable .


A hierarchy is a group of things arranged in order of rank. It is a set of transmission speeds arranged to multiplex successively higher numbers of circuits. See also Hierarchical Network. It is also an Internet USENET newsgroup hierarchy which refers to the set of all news-groups contained within a specific broad subject category.


Host Interface Node. Provides the interface between a host and the Concert Packet Service network.

High and Dry

  1. What happens when you dial into a long distance network and nothing happens. You don't hear anything. Your call doesn't go anywhere . You're simply left High and Dry. Also called Dead Air.

  2. A local central office term. The phone has been off-hook for an extended period of time. It is open in the loop. Compare with High and Wet which means the line, battery and ground, are shorted.

High and Wet

The local central office term. It means the line, battery and ground are shorted. Compare with High and Dry which means the phone has been off-hook for an extended period of time. It is open in the loop.


ASCII characters whose values exceed 127. In most bulletin board networks, The use of high-ASCII in messages is prohibited since some types of personal computers cannot correctly interpret those characters. High ASCII is now supported by HTML.

High Bandwidth

A person who is super intelligent is said to have "high bandwidth." The term is believed to have originated at Microsoft in Seattle, Washington. See also Bandwidth.

High Burst

High Burst is a term used by carriers . They use it to describe a specific type of customer call demand. A typical customer who exhibits high-burst characteristics is a telemarketer. Telemarketers use what are called predictive dialers, which offers business the ability to automatically call out using algorithms to speed up or slow down dialing. Once the system has detected a live person, the system transfers the call to an available agent. Triple the productivity of your agents and watch your contacts and sales skyrocket!"

High Capacity Service

Generally refers to tariffed, digital-data transmission service equal to, or in excess of T-1 data rates (1.544 Mbits.)

High Cost and Low Income Division

A division of the Universal Service Administrative Company (USAC), a not-for-profit corporation established by the Telecommunication Act of 1996, and operating under the supervision of the National Exchange Carriers Association (NECA). This division is responsible for disbursing funds to subsidize the cost of providing basic telephone to those who live in High Cost Areas. See also High Cost Area, Universal Service, and Universal Service Administrative Company.

High Cost Area

A term describing a serving area of a LEC (Local Exchange Carrier) in which the cost of providing local telephone service is at least 115% of the national average. Through the "settlements" process, administered by NECA (National Exchange Carrier Association) under the direction of the FCC (Federal Communications Commission), high cost LECs are compensated for this extraordinary cost through the Universal Service Fund. See also NECA, Separations and Settlements, and Universal Service Fund.

High Definition Radio

A technology from privately held Ibiquity Digital, HD radio got its official consumer launch at the Consumer Electronics Show, January 2004, with companies like Onkyo and Kenwood announcing plans to offer radios for the new standard. The digital standard, under development for years , provides higher quality audio for both AM and FM radio broadcasts, and also allows a range of special services ” identification of songs and artists on the radio display, for instance.

High Definition TV

  1. HDTV. A system standard for transmitting a TV signal with far greater resolution than specified by the current NTSC standard in North America or PAL overseas. For a full explanation, see HDTV.

  2. "A wide screen just makes a bad film twice as bad." Samuel Goldwyn, film producer.

High Density Bipolar 3

See HDB3.

High Dome

Synonym for "egghead." A scientist.

High Energy Radio Frequency Gun

HERF. Shoots a high-powered radio signal at an electronic target (such as a computer) and puts it out of commission.

High Fidelity

Systems of radio transmission and reception which permit a wide band of audio frequencies to be transmitted and/or reproduced.

High Frequency Noise

A signal frequency more than 1,000 times the normal AC power line frequency of 60 cycles. The frequency will lie between 3 and 30MHz.

High Frequency Tags

RFID are high frequency which typically operate at 13.56 MHz. They can be read from about 10 feet away and transmit data faster. But they are consume more power than low-frequency tags.

High Level Combining

A processing of combining channels or carriers at the transmitter outputs.

High Level Data Link Control

HDLC. A communications protocol that is bit oriented in which control codes differ according to their bit positions and patterns. For a much bigger explanation, see HDLC.

High Level Diplexing

A processing of combining two radio frequency carriers (usually audio and video) at the final transmitter outputs.

High Level Languages

Essentially any of the computer languages whose code is not unique to the hardware or architecture of a particular computer. High level languages are more like human language than the machine language which computers talk. High level languages translate human instructions into the machine language computers can understand, but which humans don't have to (in order to tell the computer what to do). Computer languages such as Basic, FORTRAN, COBOL and Pascal are high level languages. They are a number of levels (at a High Level) away from the actual bit manipulation (machine language, also called "bit twiddling" by the Hackers). Compare with Low Level.

High Level Modulation

Modulation at the last amplifier stage of a transmitter.

High Low Tariff

A tariff in which two prices are given for something ” a high price and a low price. The first high/low tariff from AT&T was for leased voice lines where a lower charge was made per mile for connections between routes that have much traffic (High Density) and greater charges per mile are made for all other (Low Density) routes. The High/Low tariff was significant because it was AT&T's response to competition from long distance carriers like MCI and it was one of the first moves away from nationwide rate averaging, which was the way things were done under monopoly.

High Memory Area

HMA. High Memory Area is the first 64KB of extended memory. If you're using MS-DOS 5.0 or 6.0, you can save some conventional memory (i.e. below 640K memory) by loading the operating system into HMA. Add the line DOS=HIGH to your CONFIG.SYS to use HMA for the operating system.

High Order Bit

Hobbit. Also known as a an "alt bit," high bit," and "meta bit." The most significant bit of a byte, a high-order bit generally is the first bit in a byte. Since the hobbit is the first bit in a byte, it is the first bit that a device sees, and therefore the first bit on which action is taken. The high-order bit can be used for a wide variety of purposes in a data communications environment, all of which identify to the receiving device something of significance relative to the handling of the associated data. For example, the hobbit in the header of a packet can be used by a device to indicate the priority level of the packet data packet transfer. The hobbit also can be used to indicate the highest level of addressing, in order that the network can route the data properly.

High Pass Filter

A filter which passes frequencies above a certain frequency and stops (attenuates) those below.

High Performance Computing Act

An Act passed by Congress in 1991 to foster the creation of computer "superhighways" linking computers at universities, national laboratories and industrial organizations. One objective of the High Performance Computing Program is the establishment of a gigabit/second National Research and Education Network (NREN) that will link the government, industrial and higher education communities involved in general research activities. Such a gigabit network would provide a significant increase in bandwidth compared with the existing National Science Foundation network, which is evolving from a 1.5 megabit per second (T-1) backbone to 45 megabit per second (T-3).

High Performance Computing and Communications


High Performance Parallel Interface

HIPPI. A high-speed multi- signal interface-analogous to an RS-232 interface but for high-speed computers, etc. HIPPI provides 800 (or1600) Mb/s interconnections using 32 (or 64) bit wide parallel data paths for distances up to 25 meters (or longer if use fiber). Standardization activity is in ANSI X3T9.3.

High Performance Routing

HPR. A local area networking term. HPR is the next-generation APPN ” referred to in the past as APPN+ ” that adds IP-like dynamic networking ” e.g., dynamic alternate routing in the event of path failure ” features to APPN, and uses a routing mechanism that works at Layer 2 using a RIF concept similar to that found in SRB.

High Power Amplifier

HPA. A device which provides the high power needed to shoot signals 22,000 miles plus from an earth station to a satellite.

High Rejection

The ability of a voice recognition system containing active vocabulary words to reject those sounds that do not match closely the words in its vocabulary.

High Resolution TV

Television with over 1,000 lines per screen, about double the resolution of present systems. Sometimes called HDTV, for high-definition television. We're still awaiting standards for high resolution TV. See HDTV for a bigger explanation.

High Sierra Format

A standard format for placing files and directories on CDROM, revised and adopted by the International Standards Organization as ISO 9660.

High Speed Digital Subscriber Loop


High Speed Local Network

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

High Speed Printer

Any printer which can print at over 100 lines a minute. Like many definitions, this one is arbitrary. Some people claim a dot matrix is "high speed" and a letter quality, daisy wheel is a "low speed" printer. Laser printers could be classed as high speed printers, maybe.

High Speed Register Set

Registers are storage locations within the CPU that are used to hold both the data to be operated on and the instructions to accomplish the operations.

High Speed Signal

An AT&T definition for a signal traveling at the DS-3 rate of 44.736 Mbps (million bits per second) or at either 90 Mbps or at 180 Mbps (Optical mode).

High Split

  1. A broadband cable system in which the bandwidth used to send toward the head-end (reverse direction) is approximately 6 MHz to 180 MHz, and the bandwidth used to send away from head-end (forward direction) is approximately 200 MHz to 400 MHz. The guard band between the forward and reverse directions (180 MHz to 220 MHz) provides isolation from interference. High split requires a frequency translator which transfers the originating signals to other frequency ranges at the head-end, in either direction. Historically, CATV systems used the spectrum below Channel 2 for inbound transmissions from the user premise to the head-end; that frequency range is 5-30/40 MHz.

  2. A term used in radio communications, including paging and cellular, for several ranges of frequency used to connect a remote site to a main site. For instance, the low- split might be 806.0125 MHz and the high-split 851.0125-869.9875 MHz. Frequency translators are used to transfer the signal to another frequency range from that point forward.

High Tech

A high-falutin' (i.e. overly pretentious) way of saying technology. I exorcised the term out of this dictionary out of disgust.

High Tier

A PCS cell phone service for users moving in a high-speed automobile. High- tier PCS systems are often straightforward evolutions of current digital cellular systems. In contrast, a low-tier is a PCS cell phone service for pedestrians or slow moving vehicles (no more than 30 to 40 mph). An evolution of cordless systems originally intended for in-building applications. Systems use small cells , so they can be designed with low-power transmitters and experience fewer handoffs than high-tier PCS systems (with high-speed, mobile users). Systems provide lower cost and higher-quality services, for low-speed users only.

High Usage Groups

Trunk groups established between two central office switching machines to serve as the first choice path between the machines and thus, handle the bulk of the traffic. See High Usage Trunk Group.

High Usage Trunk Group

A Bellcore definition. A trunk group that is designed to overflow a portion of its offered traffic to an alternate route.

High Water Mark

A financial term. Let's say you give a money manager $100,000 of your money to manage. You agree to pay him 20% profit-sharing of all your gains. And you agree to do this annually. Let's say one year your manager loses 20% of your money. But the next year he earns 15%. He doesn't receive any profit-sharing of your 15% until he has earned back what he lost and is above the high water mark ” the place you started. For a more formal definition, here's one from www.hedgeworks.com. High- water mark is an investor's capital basis in a given year used to determine the minimum value to which a manager's performance fee is measured. For example, a manager may only charge an investor a performance fee for any gains achieved over the investor's capital basis or the gains achieved since the last performance fee was charged.


  1. Another word for BUS. A common path or set of paths over which many channels of information are transmitted. The channels of the highway are separated by some electrical technique.

  2. The Information Superhighway. In 1995, a consulting firm called Ovum defined the superhighway as a mechanism for providing access to electronic information and content held on network servers. It has four key features, according to Ovum: A. It supports two way communications. B. It offers more than just simple voice telephony. C. It is interactive and provides real-time, cooperative communications, and D. It supports electronic screen- based applications.

Highway Construction Supervisor

A consultant to provide assistance in specification, installation and/ or operation of systems and software for accessing the information highway.

Highway Patrol

A slang term for the U.S. Congress.


An attack on a computer system in which an established TCP/IP session is redirected in mid-session to an unauthorized host system.


A high-speed standard for broadband wireless LAN applications approved by the ETSI in February 2000, consisting of three profiles for the corporate, public and home environments. HiperLAN2 operates in the 5-GHz band and offers up to 54 Mbps over the air interface.


High Performance Radio LAN.


HIgh Performance Parallel Interface. In 1989, researchers at the Los Alamos National Laboratories began work on a standard for high-speed, point-to-point data transport between supercomputers. The result of that effort was HIPPI, which later became known as HIPPI-800 and which was standardized by the ANSI X3T9.3 committee as X.3.183-1991. HIPPI also is used to move data between supercomputers or high-end workstations and peripherals (e.g., disk arrays and frame buffers) through high-capacity, non-blocking crossbar-type circuit switches. HIPPI provides for transfer rates of 800 Mbps over 32 shielded twisted pair (STP) copper wires (single HIPPI) and 1600 Mbps over 64 pairs (double HIPPI). HIPPI connections are limited to 25 meters over STP and 10 kilometers over fiber. HIPPI is currently the most common interface in supercomputing environments. Work is in progress on HIPPI-6400, which supports transmission rates as high as 6400 Mbps, or 800 MBps (MegaBytes per second), in each direction, an 8-fold increase over the original version. Also known as SuperHIPPI and GSN (Gigabyte System Network), HIPPI-6400 is compatible with HIPPI-800. Distances of 50 meters can be bridged with parallel copper cables, and 200 meters with parallel fiber-optic cables. The connection is devised in four virtual circuits in each direction, capable of supporting various combinations of traffic such as 10Base-T, 100Base-T, Fibre Channel, ATM and HIPPI-800.


  1. An imaging term. A display plotting the density of the various colors and/or values in an image.

  2. A graph of contiguous vertical bars representing a frequency distribution in which the groups or classes of items are marked at equal intervals in ascending order on the x axis, and the number of items in each class is indicated by a horizontal line segment drawn above the x axis at a height equal to the number of items in the class.


  1. When you reply to my email and say "yes," you're sending me a reply. When you reply to my email and include my original email you're sending me an email "with history." In email clients like Lotus Notes, you can select "Reply" or "Reply with History". In some, like Microsoft's Outlook, your reply typically gets sent with the history. In AOL email, you have to work hard to send the email's history. To my tiny brain, it makes sense to include history. If you answer "Yes," it would be nice to know which request you answered "Yes" to. The original logic on not including history had something to with preserving bandwidth and server size . And I'm sure that's the reason AOL makes it so incredibly difficult to send history and why virtually all AOL users don't.

  2. "She's history."


  1. Electrical interference that causes the loss or introduction of spurious bits into a data stream.

  2. Hit is the unit of measure of popularity most commonly cited by companies that have set up shop on the Internet's World Wide Web. It is the most commonly misunderstood measure. A hit is one file opening and transfer from a Web site. It is not a measure of how many people have visited your Web site. Since one file is needed for every chunk of text and every graphic element on a Web page, one mouse click by a viewer to your site may count as a dozen or more hits, depending on the complexity of your page. Also, because most Web sites contain more than one page, hits can rapidly multiply. So, using "hits" as a measure of the popularity of a Web site or the number of people who visit a web site is not accurate. There is software around that purports to measure the number of "unique visitors " or "eyeballs" to a site. That software tries to measure the number of unique IP addresses of computers visiting the site. But that software is confused by the single fact of America On Line (the largest ISP in the world) which often runs its subscribers' access to the Web from behind massive proxy servers which can even change IP addresses mid-session. See also HITS.

Hit My Clip

When a teenager says "Hit my clip," he means "Page me."


Hits is a measure of file openings done on a Web site. In the language of the Internet, hits has two meanings. The first and more common, is the number of times your Web site or a file within your Web site is accessed by people visiting it. "Hits" is often used as a measure of how popular your site is. But the measurement of "hits" is not very scientific. For example, if someone visits a home page, then jumps to another page, then comes back to the home page, that is registered as two "hits." Still, people who are selling advertising on Web pages use "hits" as a measure of how many people visit the site and therefore how much to charge for advertising. The second meaning of "hits" is how many matches you might find in a search; e.g., a Veronica search for the word "NASA" will return a long list of hits for your query.


Host Interactive Voice Response. Tying a voice response unit into a mainframe computer which has lots of data. Applications which can be produced include bank-by-phone, reservations -by-phone, etc. See Interactive Voice Response.


His Honor. Hizzoner is the way the New York City tabloids refer to the mayor of New York. They call him Hizzoner. Say it fast.


Hong Kong Internet Exchange. See IX.


Abbreviation for HOOK SWITCH, the actual electrical switch inside a phone that is controlled by the motion of the Switch Hook.


High Level Committee of ITU (International Telecommunication Union).


  1. High Level Domain. See Web Address.

  2. High Level Design.


High Level Function.


High Level Language Applications Programming Interface. An IBM API.


Home Location Register. A database that holds subscription information about every subscriber in a mobile (i.e. cellphone) network. A HLR is permanent SS7 database used in cellular networks, including AMPS (Advanced Mobile Phone System), GSM (Global System for Mobile Communications), and PCS. The HLR is located on the SCP (Signal Control Point) of the cellular provider of record, and is used to identify/verify a subscriber; it also contains subscriber data related to features and services. The HLR is used not only when you are making a call within the area of coverage supported by your cellular provider of record. It also is used to verify your legitimacy and to support the features to which you subscribe when you are roaming outside that home area. In a roaming scenario, the local service provider queries the HLR via a SS7 link. Once verified , your data is transferred via SS7 to the VLR (Visitor Location Register), where it is maintained during your period of roaming activity within the coverage area of that provider. HLR is a key element of IS-41, the predominant wireless standard in North America. See also AMPS, GSM, IS-41, PCS, SCP, SS7 and VLR.


See High Memory Area.


Hyper Master Group.


  1. Novell's Hub Management Interface. See HMI Driver.

  2. Human-to-Machine Interface.

HMI Driver

A Hub Management Interface (HMI) driver is an ODI driver running on a NetWare server that is compliant with the Novell HMI specification. A node may emulate an HMI driver by supporting the Novell NWHUB.MIB and IPX autodiscovery .


Hidden Markov Method. A common algorithm in voice recognition which uses probabilistic techniques for recognizing discrete and continuous speech.


High-Performance Management System.


Hybrid Network Design System.


Home Numbering Plan Area.

HO Tone

A cellular term. Handoff Tone. 50ms of signaling tone sent by the mobile phone on the REVC to indicate leaving the source cell site during handoff .

Hoax Virus

A warning for a computer virus that does not actually exist. Often these appear in the form of email messages which have been forwarded many times and contain dire warnings of impending doom and an urgent plea for the receiver to forward the warning on to others.


  1. A microprocessor chip developed by AT&T's Bell Labs and used in the EO handheld devices. EO was closed down for lack of sales. The EO was just plain awful .

  2. See High-Order Bit.


HOtel Billing Information Center used by hotels for getting immediate charges for long distance calls placed by their guests. A service of AT&T and the local telephone operating company delivered through a distinct and separate trunk and usually terminating on a telex machine, which prints guest long distance charges.


HOtel Billing Information System.


The word hobo comes from the time after the Civil War, when men who had lost their farms and homesteads would ride the rails looking for temporary work at the various farms that were along the railroad tracks. Because they usually carried their own hoes, the farmers called them "hoe boys."


To temporarily leave a phone call without disconnecting it. You can return to the call at any time, sometimes from other extensions. There are several types of "HOLD" on a telephone system. How they work and what lamping they put on instruments varies from phone system to phone system.

Exclusive Hold: Prevents every other telephone from picking up the call. Only the telephone instrument that put the call on hold can retrieve it.

I-Hold: Effectively the same as Exclusive Hold.

Line Hold: The call is on hold. Anyone with a phone with the held line appearing on it can pick up the phone.

Hold Recall

A telephone system feature which reminds you periodically that you've put someone on hold.

Holding Tank

A queue in which a call is held until it can either use its assigned route or overflow into the next available route.

Holding Time

The total time from the instant you pick up the handset, to dialing a call, to waiting for it to answer, to speaking on the phone, to hanging up and replacing the handset in its cradle. You are never billed for holding time. You are always billed for conversation time which is shorter than holding time. But holding time is an important figure to know when you're trying to determine how many circuits you need. For you will need sufficient circuits to take care of dialing, etc. ” even though you're not being billed for that time.

Holdup Time

The amount of time that a power supply can continue to supply the load after input power is terminated . The duration of a blackout or transfer time that a power supply can accept without any disturbance of the output. Holdup time is specified by CBEMA to be a minimum of 8 milliseconds for business and computer equipment. The typical value specified for commercial computer power supplies is 25ms. Holdup time is increased when a power supply is lightly loaded. Therefore typical computers have holdup times in the range of 100ms. This definition courtesy American Power Conversion Corp.

Holiday Factor

A call center term. A historical factor associated with a specific date and multiplied by the forecast call volume for that date in order to take into account an expected increase or decrease in the call volume. For example, if on a given day only half the usual number of calls occur for that day of the week and that time of year, the holiday factor for that date would be .5.

Hollerith Card

A punched-hole 80 column card used for storing information for input into a computer. Remember the cards you got telling you "not to fold, bend, punch, spindle, etc."? They were Hollerith Cards. They're now falling into disfavor as other, less tamper-proof methods appear.

Hollerith Code

Twelve level punched card code.

Hollow Pipeline

Jargon for a broad bandwidth circuit that has no framing. A private out-of-band signaled (CCC, Clear Coded Channel) DS1. There is no timing, framing or error connection. You input a bit stream into one end and it comes out the other end in the same order. The maximum speed for DS-1 is 1.536 Mbps. This is 1.544 Mbps less than the framing overhead of 8 Kbps.


A three-dimensional image produced by a system that uses lasers instead of lenses.

Holographic Storage

A technology still in the labs. It uses lasers and crystals rather than magnetic or optical medium to store bits of data in holograms. Holographic data storage portends big reduction in physical storage space and much quicker seek time. Images of data are stored on holographic crystals. More than a million bits of data can be stored on a single hologram, and thousands of holograms can fit on a square that is just a single centimeter. Holographic storage has no moving parts . Experts predict holographic storage will emerge as a commercially available technology by 2005, and will, once again, change the economics of data storage.

Holy War

Arguments that involve basic tenets of faith, about which one cannot disagree without setting one of these off. For example: PCs are superior to Macintoshes.


The beginning place of a cursor on a CRT screen. Usually it's the top left hand corner. The function key on an IBM PC or clone marked "Home" will take the cursor to the home position, namely the top left hand corner.

Homebrew Computer Club

In March, 1975 a peace activist, called Frederick Moore Jr. rode his bicycle around Palo Alto and Menlo Park, tacking up small 3-by-5-inch notices on bulletin boards and telephone poles. The tiny flier read in part: "Are you building your own computer? Terminal? TV Typewriter? I/O device? Or some other digital black magic box? Or are you buying time on a time-sharing service? If so, you might like to come to a gathering of people with like-minded interests. Exchange information, swap ideas, help work on a project, whatever . . ." Thirty-two people showed up at the first meeting. Over time, the group got progressively bigger as people like Steve Jobs and Steve Wozniak (founders of Apple) and Bill Gates and Paul Allen (founders of Microsoft) visited the club to make presentations, to swap equipment and to learn. The group ultimately settled for many years at the Stanford Linear Accelerator auditorium, where as many as 750 computer enthusiasts would gather twice a month. Neither graphics nor sound were common computer features in those days, so when a hobbyist, Steve Dompier, demonstrated at the fourth meeting that he had laboriously programmed his new MITS Altair computer kit to play the Beatles' "Fool on the Hill," the assembly gave him a wild standing ovation . The typical Homebrew meeting began with a "mapping" session. The moderator ” for many years Lee Felsenstein ” would point to people around the room, and each would describe what they were working on. A formal presentation would follow. The meeting would conclude with a "random access" session in which people with similar interests would cluster to share information. It was at one such meeting, in the fall of 1981, that the transition from the hobbyist era of computing to today's booming world of corporate computing took place. Mr. Felsenstein pried open the case of the first IBM PC, examined its motherboard and pointed with glee to three "blue lines" ” wires that were evidence, he proclaimed, of a hastily patched-together computer that had been rushed to market. See also Morrow, George.


See Home Page.


HomePlug is an industry alliance, including over 50 major industry participants such as Cisco, Motorola, Panasonic, Philips, Compaq, Conexant, Sharp, Texas Instruments, Radio Shack, and others, and was organized to promote the use of powerline as a medium for communications and connectivity. Powerline is sending telecom over electricity lines. See Powerline Communications.


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.

Home Phoneline Networking Alliance

The Alliance is a consortium of more than 90 companies from the PC, consumer electronics, and network equipment manufacturing industries that are delivering easy-to-use, affordable, high-speed networking solutions over existing loop telephone wires. Its 10 Mbps home networking standard, called 2.0, has been finalized. Home networking allows multiple members of a household to simultaneously use PCs or consumer electronic devices to access files from local servers and from the the Internet, print documents, and play video games from external Internet connections including cable TV, Digital Subscriber Line (DSL), satellite or conventional analog modems. See the previous definition. www.homepna.org.


What Americans mean by homeland, the Russians use the word motherland and the Germans use the word fatherland. Essentially, homeland to Americans means the United States of America. Homeland came into use in late 2001 after the September 11 attack on New York City's World Trade Center. Shortly after the attacks, President George W. Bush formed The Office of Homeland Security, whose job is "coordinating national strategy to strengthen protections against terrorist threats or attacks in the United States."


Home Radio Frequency. A wireless networking specification from the HomeRF Working Group for interoperable voice and data communications in the unlicensed 2.4 GHz band, known as the ISM (Industrial, Scientific and Medical) band. The ISM band is shared with garage door openers, cordless telephones, RF bar code scanners, microwave ovens, and a wide variety of other devices, all of which can (and do) interfere with each other. The ISM band also is shared with IEEE 802.11b WLANs (Wireless Local Area Networks). HomeRF makes use of the SWAP (Shared Wireless Access Protocol). See also 802.11b and ISM.

HomeRF Working Group

Home Radio Frequency Working Group, or HRFWG. An organization "formed to provide the foundation for a broad range of interoperable consumer devices by establishing an open industry specification for wireless digital communication between PCs and consumer electronic devices anywhere in and around the home." The Shared Wireless Access Protocol (SWAP) specification is intended to enable interoper- ability of electronic devices from a large number of manufacturers, while providing the flexibility and mobility of a wireless solution. SWAP is expected to yield a wireless home network to share voice and data between devices such as PCs, peripherals, PC-enhanced cordless phones, and devices yet to be developed. According to its Web site, the HRFWG "was formed to provide the foundation for a broad range of interoperable consumer devices by establishing an open industry specification for wireless digital communication between PCs and consumer electronic devices anywhere in and around the home." The Shared Wireless Access Protocol (SWAP) specification is intended to enable interoperability of electronic devices from a large number of manufacturers, while providing the flexibility and mobility of a wireless solution. SWAP is expected to yield a wireless home network to share voice and data between devices such as PCs, peripherals, PC-enhanced cordless phones, and devices yet to be developed. www.homerf.org. See also HomeRF.

Home Agent

A Mobile IP term. Mobile nodes associated with nomadic users register their presence at a remote location through a foreign agent. The foreign agent communicates with the home agent in order that data packets can be forwarded to the remote subnet. See also Mobile Agent and Mobile IP.

Home Automation

HA. Home Automation is basically anything that gives us remote or automatic control of things around the home ” like lights, sound systems, security systems, thermostats, irrigation, door openers, etc. You control your remote gadgetry typically via low voltage cabling, via wireless connections (typically 802.11b) or with powerline systems, such as X10.

Home Carrier

The cellular operating company which a subscriber is registered with and pays the monthly service charge and usage charges to.

Home Location Register

HLR. A wireless telecommunications term. The knowledge center of the network, helping to route calls and ensure security. A HLR has a built-in Authentication Center (AuC), which is a database of subscriber information, including access rights and services subscribed to. A permanent SS7 database used in cellular networks, including AMPS (Advanced Mobile Phone System), GSM (Global System for Mobile Communications), and PCS. The HLR is located on the SCP (Signal Control Point) of the cellular provider of record, and is used to identify/verify a subscriber; it also contains subscriber data related to features and services. The HLR is used not only when you are making a call within the area of coverage supported by your cellular provider of record. It also is used to verify your legitimacy and to support the features to which you subscribe when you are roaming outside that home area. In a roaming scenario, the local service provider queries the HLR via a SS7 link. Once verified, your data is transferred via SS7 to the VLR (Visitor Location Register), where it is maintained during your period of roaming activity within the coverage area of that provider. HLR is a key element of IS-41, the predominant wireless standard in North America. See also AMPS, GSM, IS-41, PCS, SCP, SS7 and VLR.

Home Office

The most common form of telecommuting , in which employees work at home one or more days per week. See also VPN.

Home Page

The classic definition: The front page of an "online brochure" about an individual or organization. The Internet definition: The first page browsers see of the information you have posted on your computer attached to the World Wide Web is your "home page." It's a "welcome" page. It says "Welcome to my site, my home." It typically contains some sort of table of contents to more information which a visitor (browser, surfer, etc.) will find at your site by clicking onto hypertext links you've created. In a Web site, a home page is usually called index.htm, index.html or index.asp. The biggest mistake made by people creating Web sites is that they fail to call their home page index.* (that star depends on the operating system which the Web hoster is using). See HTML, Internet, Streaming and World Wide Web.

Home Run

Phone system wiring where the individual cables run from each phone directly back to the central switching equipment. Home run cabling can be thought of as "star" cabling. Every cable radiates out from the central equipment. All PBXs and virtually all key systems work on home run cabling. Some local area networks work on home run wiring. See Loop Through.

Home Run Cabling

There are basically two ways you can install phone cabling in a home. The old fashioned way is to instal loop wiring ” one or two pairs of wiring loop through the home, from one outlet to another. With loop wiring you install single line or two line phones around the house. Typically anyone picking up the phone can answer an incoming call or can hear the conversation. The second way to install wiring to home run cabling ” in which individual cables are run directly from a central location, which may be a telephone switch or a cross-connect panel. This configuration is also known as star topology. The advantage of home run or star cabling is typically you have privacy ” on one can pick up the phone while you're talking and most importantly, you can have an intercom. You can dial from one phone to other.

Newton[ap]s Telecom Dictionary
Newton[ap]s Telecom Dictionary
ISBN: 979387345
Year: 2004
Pages: 133

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