GR-485- CORE -Gzip


GR-485-CORE specification contains the generic guidelines for Common Language Equipment Coding Processes and Guidelines (CLEI codes)m which are a standard method of identifying telecommunications equipment in a uniform, feature-oriented language. It's a text/ barcode label on the front of all equipment installed at RBOC facilities et. al. that facilitates inventory, maintenance, planning, investment tracking, and circuit maintenance processes. Suppliers of telecommunication equipment give Bellcore technical data on their equipment, and Bellcore assigns a CLEI code to that specific product. See CLEI.

Grace Login

Allows a user to finish logging on using an expired password without changing it. You can set the number of grace logons a user is allowed.

Graceful Close

Method terminating a connection at the transport layer with no loss of data.

Graceful Degradation

A condition in which a system continues to operate , providing services in a degraded mode rather than failing completely. See ABEND.

Graceful Discard

GD. A Frame Relay term . A congestion management mechanism in Frame Relay networks. Based on agreement between the user organization and the Frame Relay service provider (i.e., carrier), associated with every PVC (Permanent Virtual Circuit) is a CIR (Committed Information Rate). The CIR is the level of data traffic (in bits) which the carrier agrees to handle over a period of time. The Offered Load to the network can burst above the CIR for a measured interval of time (T). Burst levels are measured as Bc (Committed Burst Size), which is the maximum amount of data that the carrier agrees to transfer under normal circumstances, and Be (Excess Burst Size ), which is the maximum amount of additional data that the carrier will attempt to handle, assuming that congestion conditions in the network permit. Data bits at the Be level are contained within frames, of course, as are all data bits in the Frame Relay world. The excess frames at the Be level will be marked as DE (Discard Eligible), either by the user's Frame Relay Access Device (FRAD) or by the carrier's FRND (Frame Relay Network Device), which typically is a router that sits at the edge of the carrier network. The DE frames which fall within the Be will be discarded gracefully (i.e., only when absolutely necessary) by the carrier during periods of congestion. If the network is not congested , the carrier will deliver the excess frames and bits. Typically, at the point of network ingress, the carrier will discard any frames above the Bc+Be-and not very gracefully, I might add. See also Committed Burst Size, Committed Information Rate, Discard Eligible, Excess Burst Size, FRAD, Frame Relay, FRND, Measurement Interval, Offered Load, Permanent Virtual Circuit, and Router.

Grade 1 Cable

Twisted pair cables specifically designed for analog voice circuits and data transmissions up to 1 Mbps. Applications ” Key systems, analog and digital PBX, low speed data, RS-232, etc.

Grade 2 Cable

Twisted pair cables designed to meet the IBM Type 3 specification. These cables are capable of data transmissions at 4 Mbps, IBM 3270, STAR-LAN I, IBM PC Network, ISDN, etc.

Grade 3 Cable

Twisted pair grade 3 LAN cables have performance characteristics that permit data transmissions at 10 Mbps. Each have been tested to insure they meet the EIA/TIA 568 emerging standard. Applications ” 802.3 10BASE-T at 10 Mbps, STARLAN 10 and 802.5 token ring at 4 Mbps.

Grade 4 Cable

The highest quality twisted pair cables available. Super grade cables have been tested up to speeds of 20 Mbps, 802.5 token ring at 4 Mbps and 802.3 10Base-T at 10 Mbps.

Grade 5 Cable

These are the IBM-type individually shielded 2 pair twisted data cables. They're currently being tested for data rates at 100 Mbps. Applications ” IBM Cabling System, 802.5 token ring at 16 Mbps and FDDI at 100 Mbps. Grade 5 cable is not the same as CAT 5 cable. See Category of Performance.

Grade Of Service

GOS. A term associated with telephone service indicating the probability that a call attempted will receive a busy signal, expressed as a decimal fraction. Grade of service may be applied to the busy hour or to some other specified period. A P.01 Grade of Service means the user has a 1% chance of reaching a busy signal. See Traffic Engineering.

Graded-Index Fiber

Graded-index fiber is a type of MultiMode Fiber (MMF) optical cable that is improved over earlier step-index fiber. Graded-index fiber has a thinner inner core and a gradual, rather than an abrupt, change in refractive index between the core and the cladding. The change in refractive index supports higher speed signal propagation for errant light pulses. The gradual change in the refractive index takes into account the fact the different light pulses travel in different modes (i.e., physical paths), some of which are longer than others. Both the smaller diameter of the inner core and the gradual change in refractive index make graded-index fiber much better at overcoming modal dispersion. As graded-index fiber can support transmission at 100 Mbps over distances of 2km or so, it is widely used in LAN backbones to interconnect high speed switches, routers, servers, etc. See also Modal Dispersion, MMF, Refractive Index and Step-Index Fiber.


In graphics, having an area smoothly blend from one color to another, or from black to white, or vice versa. See Gradient Fill.

Gradient Fill

A computer imaging term. A fill composed of a smooth blend from a starting color to an ending color. There are many variations on this theme. Most programs let you apply textures, and others have "smart" gradient fill routines that lend a three- dimensional appearance.

Gradium Glass

Gradium glass is capable of reducing optical aberrations inherent in conventional lenses and performing, with a single lens, tasks traditionally performed by multi-element conventional lens systems. By reducing optical aberrations and the number of lenses in an optical system, Gradium glass may provide more efficient light transmission and greater brightness, lower production costs, and a simpler, smaller product. Gradium glass is used in collimation in fiber optics. See Collimation.


The name of the handwriting recognition software used by Palm and other hand-held devices.

Grand Alliance

Also known as HDTV Grand Alliance. Comprises AT&T, General Instrument Corporation, Massachusetts Institute of Technology, Philips Electronics North America Corporation, Thomson Consumer Electronics, The David Sarnoff Research Center, and Zenith Electronics Corporation. These organizations had developed and promoted competing digital standards for HDTV. In May 1993, and under pressure from the FCC, they joined together in a "Grand Alliance" to develop a final digital standard for HDTV, which then became known as ATV (Advanced TV). The resulting single standard was documented in the ATSC (Advanced Television Systems Committee) DTV (Digital TV) Standard, which was accepted in large part by the FCC in December 1996. See ATV and HDTV.

Grand Pooh-Bah

See GPB.

Grandfather Clause

See Grandfathered.

Grandfather Tape

The first backup of a program or a data record, saved so that you can always go back to step one if something goes wrong.


A piece of equipment or service that has a right to exist at the price it is being charged and in the configuration it is by reason of it being that thing before laws or rules were introduced to change it all. The term goes back to the Civil War. Grandfathering was a provision in several southern state constitutions designed to enfranchise poor whites and disfranchise blacks by waiving voting requirements for descendants of men who voted before 1867. The word derives from a "grandfather clause." Grandfather clauses stated that the right to vote was only available to those Americans whose grandfathers had been eligible to vote. These clauses were used, primarily in the South, to discriminate against blacks and immigrants shortly after Lincoln's issuance of the Emancipation Proclamation and congressional ratification of the Fourteenth Amendment. As a result, "grandfather" has come to mean something allowable because it was allowable before prohibitive legislation. See also Grandfathered Equipment.

Grandfathered Equipment

Non-FCC registered telephone equipment that was directly connected to the telecommunications network without a phone company-provided protective connecting arrangement (PCA) prior to the formalized FCC registration program. See Grandfathered.


The people who think your children are wonderful even though they're sure you're not raising them right.


  1. Microsoft Corporation jargon for complexity. For example, when you "achieve granularity," you grasp the complexity of the issue or problem.

  2. Scalable in the most agreeable terms. A granular technology is scalable in very small increments, like grains of sand. In other words, it can be upscaled in small increments , matching the small, incremental requirements of the user while avoiding disproportionately large increases in cost. It's an overused , overly optimistic, and misleading term which finds its application primarily in sales presentations and brochures . See Brochureware.

Graphic Character

A character, other than a character representing a control function (like Ctrl G being, in WordStar and dBASE nomenclature , to delete the character on the right) that has a visual representation normally handwritten , printed, or displayed, and that has a coded representation consisting of one or more bit combinations.

Graphic Equalizer

A device which adjusts the tone by changing specific frequencies. The tone control on a radio is a type of equalizer. A radio transmitter may amplify lowend signals better than high-end signals. An equalizer can reduce or increase the amplification of the broadcast for an even and accurate reproduction of the input.

Graphic Violator

Picture the home page of a typical Web site. Somewhere on the page is a moving graphic ” perhaps an animated GIF ” that screams at you and violates the visual integrity and consistency of the page. Most often, such graphic is designed to deliberately violate the integrity of the page. It is often a paid-for advertisement. And the advertiser wants to draw your attention to his graphic ad. After all, he paid big money for the ad.

Graphical Browser

A graphical browser is another, more commonly used, term for a World Wide Web(WWW) client program. A graphical browser can display inline graphics and allows the user to choose hyperlinks to move between hypertext documents. All browsers are graphical these days. The two leading browsers are Netscape and Microsoft Internet Explorer.

Graphical User Interface

GUI. A fancy name probably originated by Microsoft which lets users get into and out of programs and manipulate the commands in those programs by using a pointing device (often a mouse). Microsoft's own definition is more elaborate. Namely that GUI puts visual metaphor that uses icons representing actual desktop objects that the user can access and manipulate with a pointing device.

Graphics Coprocessor

A programmable chip that speeds video performance by carrying out graphics processing independently of the computer's CPU. Among the coprocessor's common abilities are drawing graphics primitives and converting vectors to bitmaps.

Graphics Engine

The print component that provides WYSIWYG (What You See Is What You Get) support across devices.

Graphics File

In terms of the World Wide Web (WWW), a graphics file is a file in graphics format that can be retrieved through a Web browser. The Web browser may need an add-on or file viewer in order to be able to display the file.

Graphics Interchange Format

Graphics Interchange Format (GIF) is pronounced "Jiff." GIF is a format for encoding images (pictures, drawings, etc.) into bits so that a computer can "read" the GIF file and throw the picture up on a computer screen. The advantage of GIF files of images is that they're small, i.e. few bytes. It is a format for encoding images (pictures, drawings, logos, etc.) into bits so that a computer can "read" the GIF file and display the picture up on a computer screen. GIF can only handle 256 colors. The major advantage of GIF is that it compresses the image to a very small size, thus making it faster to transmit across phone lines. As a result, the GIF format has now become the standard for putting images up on web sites. Web page authors also often use GIF images because GIFs can be interlaced, which produces a melting effect on the client screen as the image is loading. CompuServe, the on-line service, invented GIF in 1987. GIF is based on a mathematical algorithm called LZW, which is a set of mathematical formulae used to compress images into GIF files. Unisys has a patent on LZW. GIF was originally used in the electronic bulletin board world and is used primarily to carry photographs of women in semi-clad and naked poses. According to Jack Rickard, ex-publisher of Boardwatch Magazine, "some of the photographs are reasonably good, but most feature strikingly plain women rather artlessly photographed by those whose higher calling is probably more aptly found in the building trades or automotive repair." Some argue that GIF really stands for Girls in Files. (That's a joke.) See also Internet.

Graphics Mode

PCs work in two modes ” text and graphics. In graphics mode, the pixels are individually addressable. In text mode, the graphics card inside your PC throws a type font on your screen. And that's it. You can't change it. In graphics mode, you can. Graphics and text modes are mutually exclusive.

Graphics Pipeline

The conceptual framework for 3-D graphics processing. The pipeline consists of the application/scene, gemoety, triangle setup and rendering/ rasterization.

Grasshopper Fuse

A fuse that indicates that it has been blown by the movement of a piece of springy metal.


See Fiber Grating.

Grating Lobes

Secondary main lobes.

Grave Dancing

Rejoicing in someone else's disaster.

Graveyard Shift

In the 1500s, local folks started running out of places to bury people. So they would dig up coffins and would take the bones to a "bone-house" and reuse the grave. When reopening these coffins, 1 out of 25 coffins were found to have scratch marks on the inside and they realized they had been burying people alive . So they thought they would tie a string on the wrist of the corpse, lead it through the coffin and up through the ground and tie it to a bell. Someone would have to sit out in the graveyard all night the ("graveyard shift") to listen for the bell; thus, someone could be "saved by the bell" or was considered a "dead ringer."

Gravity Cell

A closed circuit cell used where a continuous flow of current is desired. This type consists of copper and zinc electrodes with copper sulfate and zinc sulfate electrolyte. These are separated because of difference in their specific gravity.


  1. Elisha Gray was an inventor who filed for a patent on his own telephone design a few hours after Alexander Graham Bell. Gray was involved in a number of lawsuits with the young AT&T, and ultimately co-founded (with Enos BARTON) electrical equipment maker Western Electric, which was later sold to American Bell, which became AT&T. In 1984, Western Electric was renamed AT&T Technologies, and was spun off from AT&T in 1996 as part of Lucent Technologies. Stay tuned for another 10 years or so to see what becomes of Mr. Gray's company.

  2. In America, it's gray. In Britain, Australia, New Zealand and South Africa, it's grey.

Gray Code

A code used for translating certain analog representations into binary representations, such as the representation of angle. Gray code may also be called cyclic binary code or reflective code.

Gray Lady

An endearing term for the New York Times newspaper.

Gray Scale

The spectrum, or range, of shades of black that an image has. An optical pattern consisting of discrete steps or shades of gray between black and white. Early facsimile machines could only receive black and white images and print them in black or white. Now they can print 16 shades of gray. This way if they receive a photo, it will look like a photo.

Gray Whale

One of the first non-Bell key systems sold in North America. It was a 1A2 electromechanical key system from TIE/communications. TIE was a shortening of the words Telephone Interconnect Equipment. It was a wonderfully reliable phone system. A gray whale is now a prized possession.


Probably the oldest distributor of phone equipment, as well as various electrical products. Named for Elisha GRAY and Enos BARTON, who formed Western Electric. The company is headquartered in St. Louis, though there is a famous Graybar building in Manhattan, attached to Grand Central Terminal. A plaque in the terminal near stairs leading into the Graybar building shows Gray and Barton (if it hasn't been defaced or stolen).


Older, more mature executives and scientists who are typically more conservative and more skeptical than the younger workers on the team. Consent of the graybeards is typically required for any wild-eyed R&D idea in the military or bigger companies.

Grayscale Monitor

Any monitor capable of showing levels of gray and not just black or white.


Generic Routing Encapsulation. An Internet term. GRE is one of the basic operations performed by tunnel servers when tunneling through the Internet in order to provide a secure VPN (Virtual Private Network). GRE simply provides for the encapsulation of one data packet inside another data packet. The original packet becomes the payload (i.e., data field, or content) for the final packet, which also includes a new header and trailer. Tunnel servers also encrypt the payload, and continuously authenticate the identity of the communicating machines on a packet-by-packet basis. GRE for IPX tunneling is defined by the IETF (Internet Engineering Task Force) in RFC 1701, and for IP-in-IP or bridge tunneling in RFC 1702. See also IETF, IP, IPX, Packet, and VPN.

Grease Monkey

The word "grease monkey" comes from the person (usually a young boy) that would crawl up in the rafters to grease all of the pulleys and belts that ran all of the equipment in a blacksmith shop or machine shop.

Great Circle

A circle defined by the intersection of the surface of the Earth and any plane that passes through the center of the Earth. The shortest distance, over the idealized surface of the Earth, between two points, lies along a great circle.

Great Wall of China

A vast Chinese defensive fortification begun in the 3rd century B.C. and running along the northern border of the country for 2,400 kilometers or 1,500 miles.

Greek Prefixes

Remember the word "chronous?" It's used to mean the process of adjusting intervals or events of two signals to get the desired relationship between them. Here are the Greek prefixes that describe different timing conditions:

asyn - not with

hetero - different

homo - the same

iso - equal

meso - middle

piesio - near

syn - together


Green is a term being applied by manufacturers to mean their equipment uses less electricity than other equipment. Classic PC equipment include screens that shut themselves almost down if they haven't been accessed for a minute or two. Much of the technology of "green" has already been used in laptops. When it moves to the desktop, there are occasionally compromises ” such as moving from a 3/4rds off to full-on might take a moment or two. Are you willing to live with it?

Green Bean

A consultant who has no practical experience, i.e. most of them.

Green Eggs and Ham

Dr. Seuss wrote "Green Eggs and Ham" after his editor dared him to write a book using fewer than 50 different words. He never made it as a lexicographer, like me. Lucky man.

Green Energy

See Green.


Also spelled green field. Greenfield is a fancy way of saying new. It is the opposite of "legacy". A greenfield telecom network is one that is being designed and built from scratch, with no need to accommodate legacy (i.e., old) equipment or architectures. Usage extends to almost any aspect of describing a new venture: greenfield companies, greenfield evaluation, greenfield opportunities, greenfield factors, etc. An existing network being expanded has both greenfield and "brownfield" components . A variant is to describe a greenfield effort as a "greenstart." See Brownfield and Legacy.


A business that uses the fact that it recycles to promote itself.

Greenwich Mean Time

GMT. Also called Zulu Time (Z) and Universal Time Coordinated (UTC). Greenwich is a borough in South East London, England. It is located on the prime meridian, which is zero degrees geographic longitude. Greenwich was formerly the site of the Greenwich Observatory. For historic reasons, Greenwich is the place from which world time starts. When it is midnight there, it is 00:00:00:0000, or "all balls." For example, Greenwich Mean Time (GMT) is five hours later than United States Eastern Standard Time ” i.e. the time in the northern hemisphere summer. Local time ” what it was at your place ” used to be good enough for business and government International shipping and commerce changed all of that many years ago, creating the need for a global standard and reference point. GMT was created in October 1884 to satisfy that need, with the reference being the average (i.e., mean) time it takes the earth to rotate from noon-to-noon as measured from the Greenwich Meridian Line, or prime meridian, which runs through the principal Transit Instrument at the Royal Observatory in Greenwich, England. The Greenwich Meridian Line is used as it is at zero degrees longitude, thereby serving as the reference point for all measurements of longitude. Although GMT technically has been replaced by Coordinated Universal Time (UTC), it still is widely regarded as the correct time for every international time zone. Communication network switches are typically coordinated on UTC, which is based on GMT, but is controlled by highly sensitive atomic clocks which keep accurate time measured in microseconds or better. See also UTC and Zulu Time.

Greetings Only Mailboxes

Mailboxes that deliver a message to incoming callers but do not allow a message to be left. The Greeting Only Mailbox may transfer a caller to a designated telephone number.


Dual-reflector antenna system employing a paraboloidal main reflector and a concave ellipsoidal subreflector.


Generalized Regular Expression Parser. A really powerful UNIX utility which can search a text file or program, finding and displaying or printing lines of computer code which contain specific character strings.


Random binary data rendered as unreadable text. For example, noise characters in a data stream are displayed as gribble. Dumping a binary file (a file containing more than plain text, such as images, etc., which must be converted to ASCII ”usually automatically ”before being sent as email) is a great way to create great gribble. ASCII is, of course, a plain text file containing letters normally found on an, um, ordinary typewriter.


Global Reach Internet Connection. An alliance of ISPs (Internet Service Providers) and IAPs (Internet Access Providers) to provide roaming capabilities for travelers. Based on proprietary standards, roamers are authenticated before being afforded Internet access. Usage is cross-billed through the GRIC clearinghouse, with fees being set by each ISP for use of its facilities by roamers. GRIC includes over 100 member ISPs in approximately 30 countries , and includes over 1,000 POPs (Points of Presence). Members include Prodigy in the U.S., and Telstra in Australia. GRIC competes with I-PASS. The IETF's Roamops working group is developing a standard for roaming, as well. See also I-PASS and Roamops.


  1. That element in a vacuum tube having the appearance of a grid and which controls the flow of electrons from the filament to the plate. "Grid" generally refers to the control grid.

  2. Global Resource Information Database: part of the United Nations environment program.

  3. A nickname for Internet2. See Internet2.

Grid Computing

A type of distributed computing in which a wide- ranging network connects multiple geographically disperse computers. Thereby, the users gain a unified view of multiple computing resources such as CPU cycles, disk space, software and files. Grid computing includes what is often called "peer-to-peer" computing. Open Grid Services Architecture is a standard set of protocols developed for grid computing by the Open Grid Services Architecture Working Group (OGSA WG) of the Global Grid Forum (GGF). More information is available at

MIT's Technolgy Review writes : "In the 1980s internetworking protocols allowed us to link any two computers, and a vast network of networks called the Internet exploded around the globe. In the 1990s the "hypertext transfer protocol" allowed us to link any two documents, and a vast, online library-cum-shoppingmall called the World Wide Web exploded across the Internet. Now, fast emerging "grid protocols" might allow us to link almost anything else: databases, simulation and visualization tools, even the number- crunching power of the computers themselves. And we might soon find ourselves in the midst of the biggest explosion yet. "We're moving into a future in which the location of [computational] resources doesn't really matter," says Argonne National Laboratory's Ian Foster. Foster and Carl Kesselman of the University of Southern California's Information Sciences Institute pioneered this concept, which they call grid computing in analogy to the electric grid, and built a community to support it. Foster and Kesselman, along with Argonne's Steven Tuecke, have led development of the Globus Toolkit, an open-source implementation of grid protocols that has become the de facto standard. Such protocols promise to give home and office machines the ability to reach into cyberspace , find resources wherever they may be, and assemble them on the fly into whatever applications are needed. Imagine, says Kesselman, that you're the head of an emergency response team that's trying to deal with a major chemical spill. "You'll probably want to know things like, What chemicals are involved? What's the weather forecast, and how will that affect the pattern of dispersal? What's the current traffic situation, and how will that affect the evacuation routes?" If you tried to find answers on today's Internet, says Kesselman, you'd get bogged down in arcane log-in procedures and incompatible software. But with grid computing it would be easy: the grid protocols provide standard mechanisms for discovering, accessing, and invoking just about any online resource, simultaneously building in all the requisite safeguards for security and authentication. Construction is under way on dozens of distributed grid computers around the world ” virtually all of them employing Globus Toolkit. They'll have unprecedented computing power and applications ranging from genetics to particle physics to earthquake engineering. The $88 million TeraGrid of the U.S. National Science Foundation will be one of the largest. When it's completed later this year (2003) the general-purpose, distributed supercomputer will be capable of some 21 trillion floating-point operations per second, making it one of the fastest computational systems on Earth. And grid computing is experiencing an upsurge of support from industry heavyweights such as IBM, Sun Microsystems, and Microsoft. IBM, which is a primary partner in the TeraGrid and several other grid projects, is beginning to market an enhanced commercial version of the Globus Toolkit. Out of Foster and Kesselman's work on protocols and standards, which began in 1995, "this entire grid movement emerged," says Larry Smarr, director of the California Institute for Telecommunications and Information Technology. What's more, Smarr and others say, Foster and Kesselman have been instrumental in building a community around grid computing and in advocating its integration with two related approaches: peer-to-peer computing, which brings to bear the power of idle desktop computers on big problems in the manner made famous by SETI@home, and Web services, in which access to far-flung computational resources is provided through enhancements to the Web's hypertext protocol. By helping to merge these three powerful movements, Foster and Kesselman are bringing the grid revolution much closer to reality. And that could mean seamless and ubiquitous access to unfathomable computer power."


Gradient index. Generally refers to the SELFOC lens often used in fiber optics.


A computer complaint.


Grok comes from the 1961 sci-fi classic novel "Stranger in a Strange Land" by Robert A. Heinlein. Grok was a Martian word meaning "to drink" and metaphorically "to be one with." In contemporary usage among the techie crowd , you grok something if you understand it so completely that know it so intimately and exhaustively that you are "one with it," i.e., it is part of your very being. If you read this dictionary thoroughly, you will grok the language of telecom. See also Zen.


In telephony, terms associated with more efficient use of T-1 trunks by combining partially filled input T-1 trunks into fully filled outgoing T-1 trunks.


Consolidating or segregating traffic for efficiency. Managing bandwidth on a wide area, public or private network to use the long haul transmission facilities as effectively as possible. The basic concept is much like that of grooming your hair with a comb or brush, which is a matter of getting things in nice, neat little bundles which you then organize by direction through a part or a mechanism like a beret or a clip. Grooming of network traffic takes place at various points in the network, like COs (Central Offices), tandem offices, POPs (Points Of Presence), or peering points. At those physical locations, incoming traffic is organized by attributes such as type (e.g., voice, Frame Relay, and ATM), destination, and QoS (Quality of Service) requirement. Once organized, traffic with similar attributes is aggregated (i.e. joined together) and sent over outgoing circuits. Different types of traffic headed for the same destination, or intermediate point in the network, can share the same circuit, as long as each traffic type is separated by some sort of framing convention so that one can be distinguished from another.

Gross Additions

A cellular industry term. The amount of new subscribers signing up for the service before adjusting for disconnects (churn).

Gross Margin

A financial term, gross margin is the percentage of sales remaining after the costs of production are subtracted. To get to net profit from gross margin, you deduct marketing, sales and overhead costs.


Connecting equipment by some conductor (wire) to a route that winds up in the earth (ground), or some suitable alternative, for electrical purposes. A "hard ground" is a direct connection between a device to ground through a wire or other conductor that has a negligible resistance to ground. One purpose of a "ground" wire is to carry spurious voltage (e.g. lightning strikes) away from the electrical and electronic circuits to which it can cause harm. Incorrect grounding is probably the major cause of telephone systems problems. See Grounding (the major explanation), Ground Return and Ground Start.

Ground Absorption

The loss of energy in transmission of radio waves due to dissipation in the ground.

Ground Block

A device used to ground the shield of a coaxial cable usually at the point where the cable enters a building.

Ground Bulkhead

A special grounded metal entrance plate to which the shields of up-tower transmission lines, waveguides, or other up-tower cables are bonded.

Ground Button

A button needed on phones used for power failure transfer behind a PBX. You need the button because many trunks behind a PBX are ground start (as compared to loop start).

Ground Clamp

A clamp or strap used to provide make a secure connection to a water pipe or grounding rod. It connects a wire to earth ground.

Ground Constants

The electrical constants of the earth, such as conductivity and dielectric constant. The values vary with frequency, and also with local moisture content and chemical composition of the earth.

Ground Fault

In AC electricity, a ground fault is any unintended connection between a supply conductor and ground (i.e.: hot conductor in contact with the metal case of a piece of equipment). A ground fault will cause a high current flow and should operate the over- current protection (fuse or breaker provided such devices are functionally adequate) only if the ground path impedance is sufficiently low ” but under no circumstances greater than two ohms.

Ground Fault Circuit Interrupter

GFCI or GFI. A device intended to interrupt the electrical circuit when the fault current to ground exceeds a predetermined value (usually 4 to 6 milliamps) that is less than required to operate the overcurrent protection (fuse or breaker) for the circuit. This device is intended to protect people against electrocution. It does not protect against fire from circuit overload.

Ground-Fault Current Path

An electrically conductive path from the point of a ground fault on a wiring system through normally non-current-carrying conductors, equipment, or the earth to the electrical supply source.

Ground Fault Protector

GFP. A device designed to protect electrical service equipment from arcing ground faults. A GFP does not provide protection for people.

Ground Kit

A kit of the parts necessary to ground the shield of a coaxial cable or body of a waveguide to the structure of an antenna tower at periodic intervals.

Ground Lead

The conductor leading to the ground. Connection.

Ground Loop

This occurs when a circuit is grounded at one or more points. It can cause telephone system problems. Here's an explanation from American Power Conversion Corp.: Common wiring conditions where a ground current may take more than one path to return to the grounding electrode at the service panel. AC powered computers all connected to each other through the ground wire in common building wiring. Computers may also be connected by data communications cables. Computers are therefore frequently connected to each other through more than one path. When a multi-path connection between computer circuits exists, the resulting arrangement is known as a "ground loop". Whenever a ground loop exists, there is a potential for damage from inter system ground noise.

Ground Mount

A flat plate used for mounting antenna masts on the ground or sometimes on flat roofs.

Ground Noise

Thermal Noise emanating from either an electrical ground or from the earth itself.

Ground Plane

The surface existing or provided, that serves as the near-field reflection point for an antenna.

Ground Potential

The electrical potential of the earth with respect to another body or region. The ground potential of the earth will vary with locality and also as a function of certain phenomena such as meteorological disturbances.

Ground Radials

Horizontal copper rods buried at the base of an antenna tower to establish an earth ground either for lightning protection or for a propagation plane depending upon the type of antenna being used.

Ground Return

If a battery is connected to a closed electrical circuit, an electric current will flow in the circuit. In the early days of the telegraph, the circuit consisted of a long wire, the telegraph key, the electromagnet of a telegraph sounder and a return path through the ground, which served as a conductor. Thus the current flowed from one terminal of the battery through the wire, through the electromagnet, to a metal stake driven into the ground (a "ground" electrode), back through hundreds of miles of earth to the distant stake at the distant telegraph office and then to the other terminal of the battery. In later telecommunications, the ground return path was replaced by a second wire.

Ground Return Circuit

A circuit in which the earth serves as one conductor. A circuit in which there is a common return path, whether or not connected to earth ground.

Ground Rod

Usually a six or eight foot copper rod driven into the earth to establish an earth ground.

Ground Start

A way of signaling on subscriber trunks in which one side of the two wire trunk (typically the "Ring" conductor of the Tip and Ring) is momentarily grounded (often to a cold water pipe) to get dialtone. There are two types of switched trunks typically for lease by a local phone company ” ground start and loop start. PBXs used to work best on ground start trunks. Now most work on loop start. Normal single line phones and key systems typically work on loop start lines. You must be careful to order the correct type of trunk from your local phone company and correctly install your telephone system at your end ” so that they both match. In technical language, a ground start trunk initiates an outgoing trunk seizure by applying a maximum local resistance of 550 ohms to the tip conductor. See Loop Start.

Ground Start Supervision

Telephone circuitry developed to prevent Glare.

Ground Start Trunk

A phone line that uses a ground instead of a short to signal the CO for a dial tone. required by some PBXs. See Ground Start.

Ground Station

A cluster of communications equipment, usually including signal generator, transmitter, receiver and antenna that receives and/or transmits to and from a communications satellite. Also called a satellite earth station.

Ground Strap

A wide copper strap used to ground equipment.

Ground to Air Paging

GAP. The ability to deliver a message (also called a page) from the ground to a user in an airplane.

Ground Wave

In radio transmission, a surface wave that propagates close to the surface of the Earth. The Earth has one refractive index and the atmosphere has another, thus constituting an interface. These refractive indices are subject to spatial and temporal changes. Ground waves do not include ionospheric and tropospheric waves.


There are two distinct and unique categories in this broad area called grounding. One is earth grounding. The purpose of an earth grounding system is essentially threefold:

  1. To guard against the adverse effects of lightning,

  2. To assist in the reduction of static and

  3. To bring a zero-voltage reference to system components in order that logic circuits can communicate from a known reference. The other category of grounding is known as equipment grounding. The purpose of equipment grounding is threefold:

    • To maintain "zero volts " on all metal enclosures under normal operating conditions. This provides protection from shock or electrocution to personnel in contact with the enclosure. This is the safety aspect. This is the primary means of protecting personnel from electrocution.

    • To provide an intentional path of high current carrying capacity and low impedance to carry fault current under ground fault conditions; and

    • To establish a zero voltage reference for the reliable operation of sensitive electronic equipment. Effective equipment grounding is defined in the National Electrical Code, Article 250-51 and the Canadian Electrical Code Article 10-500. These Codes read almost identically. They say: The path to ground from circuits, equipment and metallic enclosures for conductors shall;

  4. Be permanent and continuous.

  5. Have the capacity to conduct safely any fault current likely to be imposed on it.

  6. Have sufficiently low impedance to limit the voltage to ground and to facilitate the operation of the circuit protective devices in the circuit.

The Earth shall not be used as the sole equipment grounding conductor. According to the Electric Power Research Institute, "electrical wiring and grounding defects are the source of 90% of all equipment failures." Many telephone system installer/contractors have found that checking for and repairing grounding problems can solve many telephone system problems, especially intermittent "no trouble found" problems. As electrical connections age, they loosen, corrode and become subject to thermal stress that can increase the impedance of the ground path or increase the resistance of the connection to earth. Equipment is available to test for proper grounding. (Ecos Electronics of Oak Park, IL makes some.) Before you install power conditioning equipment such as voltage regulators, surge arresters, etc. you should test for and correct any problems you have with grounding and wiring.

This story is related by Pat Routledge of Winnepeg, Ontario, Canada about an unusual telephone service call he handled while he was living in England. It is common practice in England to signal a telephone subscriber by signaling with 90 volts across one side of the two wire circuit and ground (earth in England). When the subscriber answers the phone, it switches to the two wire circuit for the conversation. This method allows two parties on the same line to be signalled without disturbing each other. This particular subscriber, an elderly lady with several pets called to say that her telephone failed to ring when her friends called and that on the few occasions when it did manage to ring, her dog always barked first. Torn between curiosity to see this psychic dog and a realization that standard service techniques might not suffice in this case, Pat proceeded to the scene. Climbing a nearby telephone pole and hooking in his test set, he dialed the subscriber's house. The phone didn't ring. He tried again. The dog barked loudly, followed by a ringing telephone. Climbing down from the pole, Pat found: several things. First, the dog was tied to the telephone system's ground post via an iron chain and collar ; Second, every time a call came in, the dog received 90 volts of signalling current. Third, after several 90 volt jolts, the dog began to urinate on the ground. Lastly, the wet ground now conducted the 90 volt signaling current, which caused the phone rang. See also AC, AC Power and Battery.

Grounding Electrode Conductor

The conductor used to connect the grounding electrode to the equipment grounding conductor, to the grounded conductor of the circuit at the service equipment, or at the source of a separately derived system.

Grounding Field

Grounding rods placed in the ground and connected together around an antenna site or central office site. This provides the best possible ground for electronic equipment.

Grounding Strap

A device worn on the wrist or on the shoe when handling a static-sensitive component to prevent static shocks ( sparks ) which could damage the component. Don't even think of touching a printed circuit card without wearing a grounding strap. See Grounding.


  1. In call centers or in automatic call distributors , a group is the same as GATE or SPLIT. A group is an ACD routing division that allows calls arriving on certain telephone trunks or calls of certain transaction types to be answered by specific groups of employees .

  2. A group is a collection of voice channels, typically 12. In AT&T jargon, a group is 12 channels. A supergroup is 60 channels. A mastergroup is 10 supergroups or 600 voice channels.

  3. An SCSA definition. A group is an associated set of one or more Resource Objects. Groups encapsulate the functionality of the Resource Objects that are associated with them. Resource Objects within a Group have defined connectivity. The Group provides three services to the application: implicit management of connectivity between group members; representation of a single entity to the applications (group ID); and reservation of all physical resources (CPU, memory, time slots) required to provide the application with exclusive use of configured resources.

Group 1, 2, 3, 3 bis & 4

These relate to the facsimile machine business. They are essentially standards of speed and sophistication. They were created by the ITU-T in Geneva, Switzerland to make sure facsimile machines from one maker could speak to facsimile machines of another maker.

Group 1 transmits an 8 1/2 by 11-inch page in around six minutes. It conforms to ITUT Recommendation T.2.

Group 2 transmits an 8 1/2 by 11-inch page in around three minutes. It conforms to ITU-T Recommendation T.3.

Group 3 ” the most common fax in the world today ” transmits an 8 1/2 by 11- inch page (also called A4) in as little as 20 seconds. It is a digital machine and includes a 9,600 baud modem. It transmits over dial up phone lines. Group 3 standards for facsimile devices were developed by ITU-T adopted in 1980 and modified in 1984 and 1988. Group 3 defines a resolution of 203 x 98 dots per inch and 203 x 196 for "fine." Group 3 uses modified Huffman code to compress fax data for transmission. For example, a white line with no text, called a run, extending across an 8.5" page equals 1728 bits. Modified Huffman Code compresses the 1728 bits into a 17-bit code word. The lengths for all possible white runs are grouped together into 92 binary codes that will handle any white run length from 0 to 1728.

Group 3 bis. This is an update to Group 3. It includes an image resolution of 406 x 196 dpi and a transfer rate of 14,400 bits per second. Fax machines that are Group 3 bis can transmit 50% faster to fax machines that are also Group 3 bis, which is a big speed improvement. Group 3 bis can drop to Group 3 if there's a Group 3 on the other end. Most of the modern plain paper fax machines and most of the today's computer fax modems are Group 3 bis. That means they transmit and receive at up to 14,400 bps.

Group 4 Fax. The latest and fastest international standard for facsimile machines. It specifies a machine which operates at 64 Kbps, which can only work on a digital channel and which takes six seconds to transmit a 8 1/2 x 11 inch page. The Group 4 standard was promulgated in January, 1987. Group 4 fax machines are designed to use one of the 64,000 bit per second B (Bearer) channels on ISDN. The main difference between Group 3 and Group 4 fax machines is that Group 4 fax machines do not convert the scanned information into an analog format before transmitting it down phone lines. Group 4 fax machines simply send the digitally scanned information down ISDN lines. The advantages of Group 4 fax are that quality is much higher, and call costs are much lower due to the increase in speed of transmission.

Most Group 3 machines will transmit and receive from Group 1, Group 2 and Group 3 machines (but at their slower speeds). Group 1, 2, 3 & 4 are international standards. Group 3 is now by far and away the most common. All Group 3 machines will transmit and receive from each other. Some manufacturers have improved on the standards by offering Group 3 "fine," for example. These "fines" can talk to the same machines. But often can't talk to other " fines ." If you're buying a facsimile machine and want super-quality transmission, check its compatibility with other machines. Or, easier, buy all identical machines. See Facsimile.

Group Address

A single address that refers to multiple network devices. Synonymous with multicast address.

Group Addressing

In transmission, the use of an address that is common to two or more stations. On a multipoint line, where all stations recognize addressing characters but only one station responds.

Group Busy Hour

GBH. The busy hour offered to a given trunk group.

Group Call

A special type of station (i.e. extension) hunting that requires a special access number to permit a call to the special access number and ring the first available phone in that group.

Group Channel

Twelve voice-grade channels. This is one of the levels of the transmission hierarchy.

Group Distribution Frame

GDF. In frequency-division multiplexing, a distribution frame that provides terminating and interconnecting facilities for the modulator output and demodulator input circuits of the channel transmitting equipment and modular input and demodulator output circuits for the group translating equipment operating in the basic spectrum of 60 kHz to 108 kHz.

Group Hug

A group hug is Microsoft Stratgegic relationship.

Group Hunting

Automatically finds free telephones in a designated group. See Hunt.

Group Scheduling Software

Software designed to coordinate and manage both worker schedules and office resources such as equipment and conference rooms.

Group Velocity

  1. The velocity of propagation of an envelope produced when an electromagnetic wave is modulated by, or mixed with, other waves of different frequencies. The group velocity is the velocity of information propagation.

  2. In optical fiber transmission, for a particular mode, the reciprocal of the rate of change of the phase constant with respect to angular frequency.


A facsimile term for periodic error in the spacing of recorded lines.


Ohio, January 8, 1997, GRoupIPC - North America (GRoupIPC-NA) has announced their official incorporation as a non-profit organization. Susan M. Chicoine, of Systran Corp., Dayton, Ohio, who served as a trustee during the incorporation process, was elected president of the group. The parent organization, GRoupIPC, was established in Europe in 1994 to provide a worldwide forum for the exchange of information on Industry Pack (IP) and PCI Mezzanine Card (PMC) technologies. GRoupIPC-NA promotes the embedded system industry's trend towards open, internationally recognized, standards solutions reinforcing the movement away from sole-vendor, proprietary solutions that limit the flexibility and upgradeability of embedded system designs. Member organizations support open-system solutions based upon the internationally recognized PMC and IP mezzanine board standards, and will promote their use to bring the benefits of stable, multi-vendor standards to embedded designs. GRoupIPC-NA will: (1) Promote market acceptance and the use of PMC and IP mezzanine board technology, (2) Disseminate information about products, applications and technical requirements, using or affecting IP and PMC mezza- nine board technology and (3) Provide market and technical support to users, distributors, and manufacturers of IP and PMC technology and products. GRoupIPC-NA is headquartered in Dayton, Ohio., email or phone 937-427- 9735.


A term for software which runs on a local area network and which allows people on the network (typically a team) to participate in a joint (often complex) project. According to Fortune Magazine, March 23, 1992, using groupware, "Boeing has cut the time needed to complete a wide range of team projects by an average of 91%, or to one- tenth of what similar work took in the past." Groupware can be used in a meeting, with everyone sitting around a conference table and typing their ideas into the PC in front of them. Groupware can also be used off-line, with members of the "team" in different cities adding their comments. The "bellwether" of groupware software is Lotus' program called Notes.

Growth Addition

A telephone company definition. Any equipment addition that increases the limiting capacity of an entity. Hence, a trunk relay addition will not generally be considered a growth addition since trunk relay equipments are not considered as limiting. However, if a trunk relay addition requires other equipment, such as trunk frames, or other common control equipment, then the addition should be considered a growth addition.

Growth Entity

A telephone company definition. The growth entity in a multi-entity wire center is that entity where all future network access line growth is engineered to take place. Non growth entities are normally loaded at or near capacity and excess demand is served via the growth entity. This distribution of demand is accomplished via the loading plan.

Growth Factor

A telephone company definition. A ratio derived by trending network access lines, traffic or loads and relating the future levels to current levels. Growth factors may be combined to develop a projection ratio or used individually as a projection ratio.


A pig's snout is called a "gruntle."


Generic Remote Switch Unit.


Ground Separator.


Gigabit Switch Router.


Group Switch Selector.

GS Trunk

Ground Start Trunk. A trunk on which the communications system, after verifying that the trunk is idle (no ground on tip), transmits a request for service (puts ground on ring) to a telephone company. The other and more common type of trunk is called a Loop Start Trunk.


General Services Administration.


See Global Software Defined Network.


See Generic Services Framework.


GSM originally stood for Groupe Speciale Mobile. Now it's known as Global System for Mobile Communications. It is the standard digital cellular (also called mobile) phone service you will find in Europe, Japan, Australia and elsewhere ” a total of 85 countries. Most countries decided to pick a single, standard wireless phone technology years ago, and they settled on GSM. The U.S. refused to settle on a standard and that has resulted in a patchwork of multiple, incompatible technologies. GSM exists in the U.S., and is gaining ground in the U.S. though it uses a different frequency than the system used in Europe adn elsewhere. In the U.S. used by companies including VoiceStream, Cingular and AT&T, which was, at the time of writing, is in the process of converting its network to GSM.

GSM actually is a set of ETSI standards specifying the infrastructure for a digital cellular service. ETSI has trademarked ETSI. To ensure interoperability between countries, these ETSI standards address much of the network wireless infrastructure, including the radio interface (900 MHz), switching, signaling, and intelligent network. An 1,800 MHz version, DCS1800, has been defined to facilitate implementation in some countries, particularly the UK. Since GSM is limited to technical standards, an association of GSM operators called the Memorandum of Understanding (MoU) ensures service interoperability, allowing subscribers to roam across networks. GSM has gained widespread acceptance. As of mid- 1999, there were operational GSM networks in 133 countries, with over 170 million customers ” more than all the Internet subscribers in the world. GSM accounted for 65 percent of the world's cellular users.

GSM subscriber data is carried on a Subscriber Identity Module (SIM) or " smartcard " which is inserted into the phone to get it going. As a result, the subscriber potentially has the option of either SIM card mobility or terminal mobility across multiple networks.

There are now four frequency flavors of GSM: 450 MHz (upgrade of old NMT systems in Scandinavia), 900 MHz (original flavor everywhere except North America and most countries in South America), 1800 MHz (new flavor everywhere except North and South America ” brought in to add capacity and competition), and 1900 MHz (North America and much of South America, i.e. the "PCS" frequencies. IN the United States, the GSM frequencies are 1850-1910 MHz and 1930-1990 MHz.

Here's the technology of GSM: Access method: mixed TDMA & FDMA with optional frequency hopping . Security: Optional radio interface encryption. Carrier frequency division: 200 KHz. Users per carrier frequency: 8. Speech bit rate (transfer rate): full rate (13 kbps) or half rate. Total bit rate: 21 Kbps. Bandwidth per channel: 25 KHz. The audio encoding subset of the GSM standard is best known to computer users because its data compression and decompression techniques are also being user for Web phone communication and encoding .wav and .aiff files.

The best book on GSM is "The GSM System for Mobile Communications" by Michael Mouly and Marie-Bernadette Pautet, both of France. The authors contributed to the development of GSM. See also BSS, which stands for Base Station System. See also SIM Card.


Global System for Mobile Communications at 900 MHz. A wireless telecommunications term. A GSM (Global System for Mobile Communications) standard for cellular phone systems operating at 900 Megahertz. See GSM.


The European Standard for Railway Communication Technology. The European railways have developed a communication network based on GSM, called GSM-R. GSM-R will integrate all existing mobile radio applications for railway use and provide a platform for new services and applications for future evolution. In particular, GSM-R will provide a communication platform to enable the interoperability of railway traffic and provide a bearer service for the European Train Control System. European Council Directives require a fully interoperable Control and Command System on the international high-speed lines of European Union railways, and GSM-R will enable this. GSM-R brings together in a single system most, if not all, of the applications needed by the railways, including: digital technology, the integration of services based on a standardized open system, interworking with railway and public mobile and fixed communication systems, Europe-wide roaming and mobility management appropriate to railway specific services and performance. Applications for railway operation include :

  • Logistics (tracing cargo coaches, containers, goods etc, polling of status information on goods).

  • Enhanced operational services for railway staff (Intranet access to operational databases, customized news services for time scheduling and tariffs, automatic seat reservation with display).

  • Telematic applications for rolling stock and fixed equipment.

  • Optimized freight load and on-line sale of free capacity.

  • On-line passenger information systems on trains and platform.

  • Internet terminals for reliable on-train WWW services.

  • Train journey specific car rental, taxi ordering, hotel reservations , etc. Background: In 1993, the Union Internationale des Chemins de Fer (UIC) chose the GSM standard as a basis for its future digital mobile system and established the European Integrated Railway Radio Enhanced Network project (EIRENE) to co-ordinate user requirements, establish the high level specifications and to co-ordinate the related standardization and pre-operation activities. The EIRENE project produced Specifications for the interoper- ability of mobile communications. To ensure that Member States complied with these Specifications, they were converted into European Standards by ETSI (the European Telecommunications Standards Institute) and CENELEC (the European Committee for Electrotechnical Standardization. See also GSM.


  1. Gigabyte System Network. See HIPPI.

  2. Global Subscriber Number. See UIFN.


GeoStationary Orbit . The path described by a satellite that always remains fixed with respect to all points on a rotating orbited body, is circular, lies in a plane and has points that revolve about the orbited body in the same direction and with the same period as the orbited body rotation. See Geostationary Satellite and NGSO Satellite.


Global Switched Telephone Network. The GSTN essentially is the international version of the PSTN (Public Switched Telephone Network). See also PSTN.


  1. Global Title. An address such as customer-dialed digits that does not explicitly contain information that would allow routing in the SS7 signaling network. The GTT translation function is required. See GTT.

  2. Gain Transfer.


  1. Government Telecommunications Association. An association of local, state and federal telecommunications professionals in Washington, D.C.

  2. The former Canadian Government Telecommunications Agency is now called GTIS (pronounced "GEE-tiss", Government Telecommunications and Informatics Service) and is part of the department called PWGSC (Public Works and Government Services Canada).


Global Tag. A standardization initiative of the Uniform Code Council (UCC) and the European Article Numbering Association (EAN) for asset tracking and logistics based on radio frequency identification (RFID). The GTAG initiative is supported by Philips Semiconductors, Intermec, and Gemplus, three major RFID tag makers .


General Telephone and Electronics. GTE was a major telecommunications company, whose main business was owning and operating independent (i.e., non Bell) local telephone companies, which were known as GTOCs (General Telephone Operating Companies). GTE also used to own part of Sprint, the long distance company, but sold its interest to United Telecom. On July 28, 1999, Bell Atlantic announced that it was merging with (i.e., acquiring) GTE. In 2000, Bell Atlantic changed its name to Verizon. See also GTE Sprint and Verizon.

GTE Sprint

A long distance service once provided by GTE Sprint, then a 50-50 joint venture of GTE and United Telecom. In 1989, United Telecom acquired the majority interest (80.1%), and in 1991, bought the remaining 19.9%. During this time, the company became Sprint Corporation. See also Sprint.


Generic Top Level Domain. An term for Internet and World Wide Web naming. The idea of gTLD is to allow web sites with creative, descriptive names such as, which is a lot easier to remember than an IP address. The original TLDs include .com (commercial), .edu (educational institution), .gov (government), .org (non-profit organization), .net (network provider) and .mil (military). There was a proposal that beginning in March 1998, new TLDs would be created in order to expand the available address options. After much wrangling, the decision was made on November 16, 2000 to create the following new TLDs: .aero (aviation industry), .biz (business), .coop (business cooperatives), . info (general use), .museum (museums), .name (individual, personal use), and .pro (professionals). The administration of the gTLDs has now been contracted by CORE (Council Of REgistrars) to Emergent Corporation, which developed, and is to maintain and operate the Shared Registry System (SRS). The SRS is a neutral, shared, and centralized database of the all gTLDs. A large number of independent entities, known as "registrants," were authorized to register domain names , or URLs (Uniform Resource Locators), with each relying on the SRS. A URL, such as (this is not a real URL, at least not at the time of this writing), is translated into an IP address by a Domain Name Server (DNS), also known as a "resolver." See also CORE, DNS, IP Address, SRS, TLD, and URL.


Global Transaction Network. An AT&T service which adds smarts to the routing of inbound 800 calls. It offers six call processing services: Next available agent routing, call recognition routing, transfer connect service (allows agents to transfer calls to distant ACDs), network queuing, 800 select again service and multiple number database (allows multiple 800 numbers to be assigned to a single routing plan in the network, rather than each 800 number having its own unique routing plan).


General Telephone Operating Company. An obsolete term for a local telephone company owned by the GTE (General Telephone and Electronics) system. GTE was acquired by Bell Atlantic, now known as Verizon. See also GTE and Verizon.


  1. General Telemetry Processor.

  2. GPRS Tunneling Protocol. GTP handles the flow of user packet data and signaling information between the SGSN and GGSN in a GPRS network. GTP is defined on both the Gn and Gp interfaces of a GPRS network.

GTP Tunnel

Used to communicate between an external packet data network and a mobile station in a GPRS network. A GTP tunnel is referenced by an identifier called a TID and is defined by two associated PDP contexts residing in different GSNs. A tunnel is created whenever an SGSN sends a Create PDP Context Request in a GPRS network.


Global Technical Services Solutions.


Global Title Translation. The process of translating a Global Title from dialed digits to a point code (network node) address and application address (subsystem number). This process is accomplished by the STP (Signal Transfer Point) in the SS7 network. GTT is defined in IS-41B. See also Global Title Translation, IS-41, SS7, and STP.

Guard Band

See Guardband.


A narrow bandwidth between adjacent channels which serves to reduce interference between those adjacent channels. That interference might be crosstalk. Guardbands are typically used in frequency division multiplexing. They are not used in time division multiplexing, because the technology is completely different.

Guardian Agent

A Guardian Agent is similar to an Intelligent Agent (which hunts for and grabs information off of the web that you specify) only the Guardian Agent prevents certain sites, such as pornographic pages, gambling sites, or other areas you don't want a child to see, from being accessed.

Guardian Chip

GPS-equipped microcircuit that can be embedded under the skin and used to ID and track lost kids , Alzheimer's patients , or people buried in collapsed buildings . The technology has civil liberties groups concerned about possible abuses .


The process of holding a circuit busy for a certain interval after its release to assure that a necessary minimum disconnect interval will occur between calls.

Guest Book

You own a Web site. You've spent megabucks attracting people to your Web site. You want to keep in touch with these visitors so you can sell them something. So you politely ask them to fill their names and email addresses in your "guest book," and your Web server captures the names into a emailing database.

Guest Mailbox

A mailbox used by a hotel or motel to set up temporary mailboxes for their guests. At least that was the original definition. Now it seems every voice mail system comes with guest mailboxes that could be used for visitors, employees from out of town, etc. Same application as a hotel ” temporary use.


Graphical User Interface. A generic name for any computer interface that substitutes graphics for characters. GUIs usually done with a mouse or trackball . Microsoft's Windows is the most famous GUI. Second most famous is the Apple operating system. GUI is pronounced "GOO-ey." See Graphical User Interface.


Globally Unique IDentifier. GUIDs are small pieces of information which some software programs embed into documents and files which you create, file and email to others. They allow others to know who created the document and when. You can find them on most Microsoft Office products, like Word, Excel, PowerPoint, etc. I find them useful. Others find them a little more sinister. According to the New York Times Magazine of April 30, 2000 GUIDs "are making it possible to to link every document you create, message you email and chat you post with your real-world identity. GUIDs are a kind of serial number that can be linked with your name and email mail address when you register online for a product or service. IN short, a GUID is a number that is known to be unique and which is assigned to a session or user in order to identify them. See also Globally Unique IDentifier.

Guided Ray

In an optical waveguide, a ray that is completely confined to the core. See also DWDM.

Guided Wave

A wave whose energy is concentrated near a boundary or between substantially parallel boundaries separating materials of different properties and whose direction of propagation is effectively parallel to these boundaries.


In Hinduism, a guru is a personal religious teacher and spiritual guide. In contemporary techie lingo, a guru is an expert who is not only a wizard at something, but also a highly knowledgeable resource of information for others.


See 1453, up front in this dictionary.


A latex substance first discovered in 1847 and derived from the sap of Malayan evergreen trees. It first found use circa 1851 as the insulation in the first international telegraph cable which ran between England and France. Gutta-Percha was also the first insulator to survive in underseas applications (particularly for submarine cables) and was still the insulator material of choice for golf balls and telephone receivers until about 1947, when polyethylene finally began to gain acceptance.

Guy Hook

A hook bolted to telephone poles and used to attach guy wires.

Guy Thimble

A device used to attach a guy wire to a bolt which is attached to an anchor in the ground.

Guy Wire

A wire used to support radio mast, microwave antennas, telephone poles ” in short anything that is tall and thin that needs supporting ” so it doesn't fall over. Guy wires attach at various heights to what you're trying to support and are then attached to devices hammered into the ground some distance from the thing they're trying to support. Imagine a telephone pole standing in some exposed place. Let's say we attach three guy hooks equidistant around the pole, and three guy wires to each other. Bingo, the pole is supported firmly and shouldn't fall. See also Guy Hook.


A type of wireless transmission tower that is supported by thin guy wires.


The GARP VLAN Registration Protocol (GVRP) is a GARP (Generic Attribute Registration Protocol) application that provides registration services in a VLAN context. See GARP for more information.


A free compression software program available for Unix and MS-DOS. Appends either a .z or a .gz to the file name. Compressing a file makes it smaller and therefore it takes less time to transmit. The most popular programs are Winzip and PKZIP.

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