494 lines
18 KiB
Plaintext
494 lines
18 KiB
Plaintext
===============================================================================
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_ _ _______
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|_||_|etal / /hop
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__________/ /
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/___________/
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(314)432-0756
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Proudly Presents
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The MCI Telecommunications Glossary
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Part I Volume I (A - D)
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Typed by Knight Lightning
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===============================================================================
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- A -
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A & B LEADS Designation of leads derived from the
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midpoints of the two 2-wire pairs
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comprising a 4-wire circuit.
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ABBREVIATED DIALING The ability of a telephone user to
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reach frequently called numbers by
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using less than seven digits.
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Synonym: Speed Dialing
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ACCESS CHARGE A fee paid for the use of local lines.
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ACCESS CODE A digit or number of digits required
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to be connected to a privat line
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arranged for dial access.
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ACCESS LINE A telephone circuit which connects a
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customer location to a network switching
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center.
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AIRLINE MILEAGE Calculated point-to-point mileage
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between terminal facilities.
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ALL TRUNKS BUSY (ATB) A single tone interrupted at a 120 ipm
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(impulsess per minute) rate to indicate
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all lines or trunks in a routing group
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are busy.
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ALTERNATE ROUTE A secondary communications path used to
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reach a destination if the primary path
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is unavailable.
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ALTERNATE USE The ability to switch communications
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facilities from one type of service to
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another, i.e., voice to data, etc.
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ALTERNATE VOICE DATA (AVD) A single transmission facility which
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can be used for either voice or data.
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AMERICAN STANDARD CODE FOR An 8 level code developed for the
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INFORMATION INTERCHANGE (ASCII) interchange of information between data
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processing and communications systems.
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ANALOG SIGNAL A signal in the form of a continuous
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varying physical quantity, e.g., voltage
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which reflects variations in some
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quantity, e.g., loudness in the human
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voice.
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ANNUNICATOR An audible intercept device that states
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the condition or restrictions
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associated with circuits or procedures.
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ANSWER BACK An electrical and/or visual indication
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to the calling or sending end that the
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called or received station is on the
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line.
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ANSWER SUPERVISION An off-hook signal transmitted toward
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the calling end of a switched
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connection when the called party
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answers.
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AREA CODE Synonym: Numbering Plan Area (NPA).
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A three digit number identifying more
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than 150 geographic areas of the United
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States and Canada which permits direct
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distance dialing on the telephone
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system. A similar global numbering
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plan has been established for
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international subscriber dialing.
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ATTENDANT POSITION A telephone switchboard operator's
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position. It provides either
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automatic (cordless) or manual (plug
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and jack) operator controls for
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incoming and/or outgoing telephone
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calls.
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ATTENTUATION A general term used to denote the
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decrease in power between that
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transmitted and that received due to
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loss through equipment, lines, or
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other transmission devices. It is
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usually expressed as a ration in db
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(decibel).
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AUDIBLE RINGING TONE An audible signal heard by the calling
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party during the ringing-interval.
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AUTHORIZATION CODE An identification number that the
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caller enters when placing a call
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which is used for billing purposes.
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AUTHORIZED USER A person, firm, organization,
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corporation or any other entity
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authorized by the customer to send or
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receive communications over a specific
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communications network.
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AUTO ANSWER A machine feature that allows a
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transmission control unit or station to
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automatically respond to a call that it
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receives.
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AUTOMATIC CALL DISTRIBUTOR (ACD) A switching system designed to queue
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and/or distribute a large volume of
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incoming calls to a group of attendents
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to the next available "answering"
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position.
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AUTOMATIC DIALING UNIT A device which automatically generates
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a predetermined set of dialing digits.
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AUTOMATIC IDENTIFICATION OF A computer generated report showing all
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OUTWARD DIALING (AIOD) long distance calls placed over AT&T's
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toll network.
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AUTOMATIC NUMBER IDENTIFICATION (ANI) Automatic equipment at a local dial
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office used on customer dialed calls to
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identify the calling-station.
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AUTOMATIC ROUTE SELECTION (ARS) Least cost routing via AT&T CENTREX
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system.
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- B -
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BAND (1) The range of frequencies between
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two defined limits. (2) In reference
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to WATS, one of the five specific
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geographic areas as defined by AT&T.
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Synonym: BANDWIDTH.
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BANDWIDTH See BAND.
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BASEBAND The total frequency band occupied by
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the aggregate of all the voice and
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data signals used to modulate a radio
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carrier.
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BAUD A unit of signaling speed. The speed in
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baud is the number of discrete conditions
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conditions or signal elements per
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second. If each signal event represents
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only one bit condition, then Baud is the
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same as bits per second. When each
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signal event represents other than one
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bit, Baud does not equal bits per
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second.
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BELL OPERATING COMPANY (BOC) /BELL Any of the 24 AT&T affiliated
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SYSTEMS OPERATING COMPANY (BSOC) companies providing local service.
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BELL SYSTEM The aggregate of AT&T's 24 associated
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telephone companies, Long Lines,
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Western Electric, and Bell Labs.
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BILLING NUMBER The MCI term for the number which
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identifies a customer on a billing
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location level, assigned to Network
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Service Customer (by COMS). Assigned for
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each unique customer name and billing
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location. For internal use only.
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BINARY A number system that uses only two
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characters ("0" and "1").
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BIT A binary digit. The smallest unit of
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coded information.
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BITS PER SECOND (BPS) The rate at which data transmission
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is measured.
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BLOCKED CALLS Attempted calls that are not connected
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because (1) all lines to the central
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offices are in use; or (2) all connecting
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connecting paths through the PBX/switch
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are in use.
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BLOCKED ANI ANI prohibited from completing a call
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over the MCI network.
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BREAK A means of interrupting transmission,
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a momentary interruption of a circuit.
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BROADBAND A transmission facility having a
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bandwidth of greater then 20 kHz.
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BUS A heavy conductor, or group of
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conductors, to which several units of
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the same type of equipment may be
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connected.
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BUSY The condition in which facilities over
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which a call is to be connected are
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already in use.
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BUSY HOUR The time of day when phone lines are
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most in demand.
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BUSY TONE A single that is interrupted at
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60 ipm (impulses per minute) rate to
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indicate that the terminal point of a
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call is already in use.
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BYTE A group of binary digits that are
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processed by a computer as a unit.
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- C -
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CARRIER High frequency current that can be
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modulated with voice or digital signals
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for bulk transmission via cable or radio
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circuits.
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CARRIER SYSTEM A system for providing several
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communications channels over a single
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path.
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CATHODE RAY TUBE (CRT) The "television-like" screen used to
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display the output from a computer.
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CELLULAR MOBILE RADIO A system providing exchange telephone
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service to a station located in an auto
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or other mobile vehicle, using radio
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circuits to a base radio station which
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covers a specific geographical area and
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as the vehicle moves from one area to
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another, different base radio stations
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handle the call.
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CENTRAL OFFICE (CO) A telephone switching center that
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provides local access to the public
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network. Sometimes referred to as:
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Class 5 office, end office, or Local
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Dial Office.
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CENTREX, CO PBX Service provided by a switch located
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at the telephone company central office.
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CENTREX, CU A variation on Centrex CO provided by
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a telephone company maintained "Central
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Office" type switch located at the
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customer's premises.
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CENTRAL PRCESSING UNIT (CPU) The control unit within a computer which
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handles all the intelligent functions of
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the systems. In a telephone switch,
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directs all potions of the system to
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carry out their appropiate functions.
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Synonym: Common Control.
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CHANNEL A communication path via a carrier or
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microwave radio.
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CHARACTER Any letter, digit, or special symbol.
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In data transmission would be
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represented by a specific code made up
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of a group of binary digits.
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CIRCUIT A path for the transmission of
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electromagnetic signals to include all
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conditioning and signaling equipment.
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Synonym: Facility
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CIRCUIT SWITCHING A switching system that completes a
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dedicated transmission path from sender
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to receiver at the time of transmission.
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CLASS OF SERVICE/CLASS MARK (COS) A subgrouping of telephone customers or
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users for the sake of rate distinction
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or limitation of service.
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COAXIAL CABLE A cable having several coaxial lines
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under a single protective sheath.
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Usually used as a high capicity carrier
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in urban areas between interexchange and
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toll offices.
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CODEC Coder-Decoder. Used to convert analog
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signals to digital form for transmission
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over a digital median and back again to
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the original analog form.
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COMMON CARRIER A government regulated private company
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that provides the general public with
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telecommunications services and
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facilities.
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COMMON CHANNEL INTEROFFICE A digital technology used by AT&T to
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SIGNALING (CCIS) enhance their Integrated Services
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Digital Network. It uses a seperate
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data line to route interoffice signals
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to provide faster call set-up and more
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efficient use of trunks.
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COMMON CONTROL SWITCHING ARRANGEMENT An arrangement for telecommunications
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(CCSA) networks in which common controlled
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switching machines are used to route
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traffic over network routes and access
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lines. The switching machine may be
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shared with other users and is
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maintained by the telephone company.
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COMPUTER PORT/TKI PORT The interface through which the computer
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connects to the communications circuit.
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CONDITIONING EQUIPMENT Equipment modifications or adjustments
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necessary to match transmission levels
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and impedances and which equalizes
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transmission and delay to bring circuit
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losses, levels, and distortion within
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established standards.
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CONFIGURATION The combination of long-distance
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services and/or equipment that make up a
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communications system.
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CONTROL UNIT (CU) The central processor of a telephone
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switching device.
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CORPORATE ID NUMBER The MCI term for the number which
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identifies a customer on a corporate
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level. (Not all MCI customers have
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this).
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COST PER HOUR (CPH) Total cost of different services divided
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by total holding time (in minutes).
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CROSS CONNECTION The wire connections running between
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terminals on the two sides of a
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distribution frame, or between binding
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posts in a terminal.
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CUSTOMER OWNED AND MAINTAINED (COAM) Customer provided communications
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apparatus, and their associated wiring.
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CUSTOMER PREMISE EQUIPMENT (CPE) Telephone equipment, usually including
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wiring located within the customer's
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part of a building.
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CUT To transfer a sevice from one facility
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to another.
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CUT THROUGH The establishment of a complete path for
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signaling and/or audio communications.
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- D -
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DATA Any representation, such as characters
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to which a meaning is assigned.
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DATA COMMUNICATIONS The movement of coded information by
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means of electronic transmission
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systems.
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DATA SET A device which converts data into
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signals suitable for transmission over
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communications lines.
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DATA TERMINAL A station in a system capable of sending
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and/or receiving data signals.
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DECIBEL (db) A unit measurment represented as a ratio
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of two voltages, currents or powers and
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is used to measure transmission loss or
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gain.
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DELAY DIAL A dialing configuration whereby local
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dial equipment will wait until it
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receives the entire telephone number
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before seizing a circuit to transmit
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the call.
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DELTA MODULATION (DM) A variant of pulse code modulation
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whereby a code representing the
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difference between the amplitude of a
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sample and t~he amplitude of a previous
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one is sent. Operates well in the
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presence of noise, but requires a wide
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frequency band.
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DEMODULATION The process of retrieving data from a
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modulated signal.
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DIAL LEVEL The selection of stations or services
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associated with a PBX using a one to
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four digit code (e.g., dialing 9 for
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access to outside dial tone).
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DIAL REPEATING TIE LINE/ A tie line which permits direct station
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DIAL REPEATING TIE TRUNK to station calling without use of the
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attendant.
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DIAL SELECTIVE SIGNALING A multipoint network in which the called
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party is selected by a prearranged
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dialing code.
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DIAL TONE A tone indicating that automatic
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switching equipment is ready to receive
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dial signals.
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DIALING PLAN A description of the dialing
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arrangements for customer use on a
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networks.
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DIGITAL Referring to the use of digits to
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formulate and solve problems, or to
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encode information.
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DIMENSION CUSTOM TELEPHONE SERVICE AT&T's electronically programmable
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(DCTS) telephone station sets which use special
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buttons to access PBX features.
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DIRECT DISTANCE DIALING (DDD) A toll service that permits customers to
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dial their own long distance call
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without the aid of an operator.
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DIRECT INWARD DIALING (DID) A PBX or CENTREX feature that allows a
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customer outside the system to directly
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dial a station within the system.
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DIRECT OUTWARD DIALING A PBX or CENTREX feature that allows a
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station user to gain direct access to
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an exchange network.
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DROP That direction of a circuit which looks
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towards the local operator.
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DRY CIRCUIT A circuit which transmits voice signals
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and carries no direct current.
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DUAL TONE MULTI-FREQUENCY (DTMF) Also know as Touch Tone. A type of
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signaling which emits two distinct
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frequencies for each indicaated digit.
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DUPLEX Simultaneous two-way independent
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transmission.
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DX SIGNALING A long-range bidirectional signaling
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method using paths derived from
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transmission cable pairs. It is based
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on a balanced and symetrical circuit
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that is identical at both ends. This
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circuit pre[eYts an E&M lead interface
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to connecting circuits.
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===============================================================================
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This concludes Part 1 Volume I of the MCI Telecommunications Glossary. Look for
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more G-philes from The MCI School of Telecommunications Management Reference
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Guide coming soon.
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This has been a 2600 Club production
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Thanx to Taran King
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Call The Works BBS - 1600+ Textfiles! - [914]/238-8195 - 300/1200 - Always Open
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