1537 lines
67 KiB
Plaintext
1537 lines
67 KiB
Plaintext
A & B LEADS
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Designation of leads derived from the midpoints of the two
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pairs comprising a 4-wire circuit. ++
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ABBREVIATED DIALING (AD)
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Preprogramming of a caller's phone system or long distance
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company's switch to recognize a 2- to 4-digit number as an
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abbreviation for a frequently dialed phone number, and
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automatically dial the whole number.
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Synonym: Speed Dialing. ++
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ACCESS CHARGE (AC)
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Monies collected by local phone companies for use of their
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circuits to originate and terminate long distance calls.
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Can be per minute fees levied on long distance companies,
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Subscriber Line Charges (SLCs) levied directly on regular
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local lines, fixed monthly fees for special telco circuits
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(ie. WAL, DAL,T-1), or Special Access Surcharge (SAS) on
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special access circuits. ++
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ACCESS LINE (AL)
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A telephone circuit which connects a customer location to a
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network switching center. ++
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AIRLINE MILEAGE (AM)
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Calculated point-to-point mileage between terminal
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facilities. ++
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ALL TRUNKS BUSY (ATB) A single tone interrupted at a 120 ipm
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(impulses per minute) rate to indicate all lines or trunks
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in a routing group are busy. ++
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ALTERNATE ROUTE (AR)
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A secondary communications path used to reach a destination
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if the primary path is unavailable. ++
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ALTERNATE USE (AU)
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The ability to switch communications facilities from one
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type to another, i.e. , voice to data, etc. ++
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ALTERNATE VOICE DATA (AVD)
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A single transmission facility which can be used for either
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voice or data. ++
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ANALOG SIGNAL (AS)
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A signal in the form of a continuous varying physical
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quantity, e.g. , voltage which reflects variations in some
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quantity, e. g. , loudness in the human voice. ++
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ANNUNCIATOR (AN)
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An audible intercept device that states the condition or
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restrictions associated with circuits or procedures. ++
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ANSWER BACK (AB)
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An electrical and/or visual indication to the calling or
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sending end that the called or received station is on the
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line. ++
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ANSWER SUPERVISION (AS)
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An electrical signal fed back up the line by the local
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telephone company at the distant end of a long distance call
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to indicate positively the call has been answered by the
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called party. Tells billing equipment to start timing the
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call. ++
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AREA CODE (AC)
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A three digit number identifying more than 150 geographic
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areas of the United States and Canada which permits direct
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distance dialing on the telephone system. A similar global
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numbering plan has been established for international
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subscriber dialing.
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Synonym: Numbering Plan Area (NPA). ++
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ATTENDANT POSITION (AP)
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A telephone switchboard operator's position. It provides
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either automatic (cordless) or manual (plug and jack)
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operator controls for incoming and/or outgoing telephone
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calls. ++
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ATTENTUATION (AT)
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A general term used to denote the decrease in power between
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that transmitted and that received due to loss through
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equipment, lines, or other transmission devices. It is
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usually expressed as a ratio in dB (decibel). ++
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AUDIBLE RINGING TONE (ART)
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An audible signal heard by the calling party during the
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ringing-interval. ++
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AUTHORIZATION CODE (AC)
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A 5- to 14-digit number entered using a touch-tone phone to
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identify the caller as a customer of the long distance
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service. Used primarily before Equal Access as a way to
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verify the caller as a customer and bill calls. ++
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AUTO ANSWER (AA)
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A machine feature that allows a transmission control unit or
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station to automatically respond to a call that it receives. ++
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AUTOMATIC CALL DISTRIBUTOR (ACD)
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A switching system designed to queue and/or distribute a
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large volume of incoming calls to a group of attendants to
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the next available "answering" position. ++
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AUTOMATIC DIALING UNIT (ADU)
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A device which is programmed with frequently called numbers.
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The caller presses one to three digits and the preprogrammed
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number is automatically dialed into the phone circuit. ++
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AUTOMATIC IDENTIFICATION OF OUTWARD DIALING (AIOD)
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The ability of some centrex units to provide an itemized
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breakdown of charges (including individual charges for toll
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calls) for calls made by each telephone extension. ++
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AUTOMATIC NUMBER IDENTIFICATION (ANI)
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On long distance calls, the process by which the local phone
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company passes a caller's local billing phone number to
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his/her long distance company when a "1+" or "10-XXX" call
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is made. With ANI a caller's long distance carrier knows
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who (what phone number) to bill without requiring the caller
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to enter any extra digits to be identified. ++
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AUTOMATIC ROUTE SELECTION (ARS)
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Synonym: Least Cost Routing ++
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BAND
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(1) The range of frequencies between two defined limits.
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(2) In reference to WATS, one of the five specific
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geographic areas as defined by the carrier.
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Synonym: Bandwidth. ++
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BANDWIDTH
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see BAND. ++
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BASEBAND
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The total frequency band occupied by the aggregate of
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all the voice and data signals used to modulate a radio
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carrier. ++
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BAUD
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A unit of signaling speed. The speed in Baud is the number
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of discrete conditions or signal elements per second. If
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each signal event represents only one bit condition, then
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Baud is the same as bits per second. Baud does not equal
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bits per second. ++
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BLOCKED CALLS
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Attempted calls that are not connected because (1) all lines
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to the central offices are in use; or (2) all connecting
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paths through the PBX/switch are in use. ++
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BREAK
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A means of interrupting transmission, a momentary
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interruption of a circuit. ++
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BREAKEVEN POINT (BP)
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Level of usage at which the total cost of a service with a
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high fixed up-front monthly fee but low minute costs becomes
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equal to the total cost of another service with low (or
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zero) monthly fee but relatively high per minute cost. At
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usage levels higher than breakeven, the service with the
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high monthly fee is cheaper. ++
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BROADBAND
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A transmission facility having a bandwidth of greater than
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20 kHz. ++
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BUS
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A heavy conductor, or group of conductors, to which several
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units of the same type of equipment may be connected. ++
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BUSY (BY)
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The condition in which facilities over which a call is to be
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transmitted are already in use. ++
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BUSY HOUR (BH)
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The time of day when phone lines are most in demand. ++
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BUSY TONE (BT)
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A single tone that is interrupted at 60 ipm (impulses per
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minute) to indicate that the terminal point of a call is
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already in use. ++
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BYPASS (BP)
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The direct connection to customer-premises equipment by an
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IC. This occurs when an IC connects its own facilities (or
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facilities leased from a non-BOC entity) directly to an end
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user's premises, circumventing the use of the BOC network. ++
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CARRIER
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A long distance company which uses primarily its own
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transmission facilities, as opposed to resellers which lease
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or buy most or all transmission facilities from carriers.
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Many people refer to any type of long distance company,
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whether it has its own network or not, as a carrier, so the
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term is not as restrictive as it used to be. ++
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CARRIER ACCESS CODE (CAC)
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The sequence an end user dials to obtain access to the
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switched services of a carrier. Carrier Access Codes for
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Feature Group D are composed of five digits, in the form
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10XXX, where XXX is the Carrier Identification Code. ++
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CARRIER COMMON LINE CHARGE (CCLC)
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A per minute charge paid by long distance companies to local
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phone companies for the use of local public switched
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networks at either or both ends of a long distance call. ++
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This charge goes to pay part of the cost of telephone poles,
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wires, etc. ++
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CARRIER IDENTIFICATION CODE (CIC)
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The three-digit number that uniquely identifies a carrier.
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The Carrier Identification Code is indicated by XXX in the
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Carrier Access Code. The same code applies to an individual
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carrier throughout the area served by the North American
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Numbering Plan. ++
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CARRIER SYSTEM (CS)
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A system for providing several communications channels over
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a single path. ++
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CELLULAR MOBILE RADIO (CMR)
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A high capacity land mobile radio system in which an
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assigned frequency spectrum is divided into discrete
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channels that are assigned to a cellular geographic serving
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area. ++
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CENTRAL OFFICE (CO)
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With local telephone companies, the nearby building
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containing the local telco switch which provides local
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telephone service. Also the physical point where calls
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enter the long distance network. Sometimes referred to as
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Class 5 office, end office, or Local Dial Office. ++
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CENTREX, CO
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PBX Service provided by a switch located at the telephone
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company central office. ++
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CENTREX, CU
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A variation on Centrex CO provided by a telephone company
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maintained "Central Office" type switch located at the
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customer's premises. ++
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CHANNEL
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A communications path via a carrier or microwave radio. ++
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CIRCUIT A path for the transmission of electromagnetic signals to
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include all conditioning and signaling equipment.
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Synonym: Facility. ++
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CIRCUIT SWITCHING
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A switching system that completes a dedicated transmission
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path from sender to receiver at the time of transmission. ++
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CLASS OF SERVICE/CLASS MARK (COS)
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A subgrouping of telephone customers or users for the sake
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of rate distinction or limitation of service. ++
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COAXIAL CABLE (COAX)
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A cable with a solid outer shield, a space and then a solid
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inner conductor. The electromagnetic wave travels between
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the outer shield and the conductor. It can carry a much
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higher band width than a wire pair. ++
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CODEC
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Coder-Decoder. Used to convert analog signals to digital
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form for transmission over a digital median and back again
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to the original analog form. ++
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COMMON CARRIER (CC)
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A government regulated private company that provides the
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general public with telecommunications services and
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facilities. ++
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COMMON CHANNEL INTEROFFICE SIGNALING (CCIS)
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A digital technology used by AT&T to enhance their
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Integrated Services Digital Network. It uses a separate
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data line to route interoffice signals to provide faster
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call set-up and more efficient use of trunks. ++
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COMMON CONTROL SWITCHING ARRANGEMENT (CCSA)
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The use of carrier switches under a carrier's control as
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part of a customer's private network. The carrier's
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software controls and switches the customer's calls over
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private lines the customer has rented. Control of the
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switch and switching functions is done in common for all
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users using the software and switching system. ++
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CONDITIONING EQUIPMENT (CE)
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Equipment modifications or adjustments necessary to match
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transmission levels and impedances and which equalize
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transmission and delay to bring circuit losses, levels, and
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distortion within established standards. ++
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CONFIGURATION
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The combination of long-distance services and/or equipment
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that make up a communications system. ++
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CONTROL UNIT (CU)
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The central processor of a telephone switching device. ++
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COST COMPONENT (CC)
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The price of each type of long distance service and/or
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equipment that constitutes a configuration. ++
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CROSS CONNECTION (CC)
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The wire connections running between terminals on the two
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sides of a distribution frame, or between binding posts in a
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terminal. ++
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CROSS TALK (CT)
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The unwanted energy (speech or tone) transferred from one
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circuit to another circuit. ++
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CUSTOMER ACCESS LINE CHARGE (CALC)
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The FCC-imposed monthly surcharge added to all local lines
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to recover a portion of the cost of telephone poles, wires,
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etc. from end users. Before deregulation, a large part of
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these costs were financed by long distance users in the form
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of higher charges. ++
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CUSTOMER OWNED AND MAINTAINED (COAM)
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Customer provided communications apparatus and associated
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wiring. ++
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CUSTOMER PREMISE EQUIPMENT (CPE)
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Telephone equipment, usually including wiring located within
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the customer's part of a building. ++
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CUT
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To transfer a service from one facility to another. ++
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CUT THROUGH
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The establishment of a complete path for signaling and/or
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audio communications. ++
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DATA SET (DS)
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A device which converts data into signals suitable for
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transmission over communications lines. ++
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DATA TERMINAL (DT)
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A station in a system capable of sending and/or receiving
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data signals. ++
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DECIBEL (DB)
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A unit measurement represented as a ratio of two voltages,
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currents or powers and is used to measure transmission loss
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or gain. ++
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DEDICATED ACCESS LINE (DAL)
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An analog special access line going from a caller's own
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equipment directly to a long distance company's switch or
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POP. Usually provided by a local telephone company. The
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line may go through the local telco Central Office, but the
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local telco does not switch calls on this line. ++
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DELAY DIAL
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A dialing configuration whereby local dial equipment will
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wait until it receives the entire telephone number before
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seizing a circuit to transmit the call. ++
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DELTA MODULATION (DM)
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A variant of pulse code modulation whereby a code
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representing the difference between the amplitude of a
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sample and the amplitude of the previous one is sent.
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Operates well in the presence of noise, but requires a wide
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frequency band. ++
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DEMODULATION (MOD)
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The process of retrieving data from a modulated signal. ++
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DIAL LEVEL (DL)
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The selection of stations or services associated with a PBX
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using a one to four digit code (e.g., dialing 9 for access
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to outside dial tone). ++
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DIAL PULSING (DP)
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The transmitting of telephone address signals by momentarily
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opening a DC circuit a number of times corresponding to the
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decimal digit which is dialed. ++
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DIAL REPEATING TIE LINE/DIAL REPEATING TIE TRUNK (TT)
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A tie line arrangement which permits direct trunk to trunk
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connections without use of the attendant. ++
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DIAL SELECTIVE SIGNALING (DSS)
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A multipoint network in which the called party is selected
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by a prearranged dialing code. ++
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DIAL TONE (DT)
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A tone indicating that automatic switching equipment is
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ready to receive dial signals. ++
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DIALING PLAN (DP)
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A description of the dialing arrangements for customer use
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on a network. ++
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DIRECT DISTANCE DIALING (DDD)
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A basic toll service that permits customers to dial their
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own long distance call without the aid of an operator. ++
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DIRECT INWARD DIALING (DID)
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A PBX or CENTREX feature that allows a customer outside the
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system to directly dial a station within the system. ++
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DIRECT OUTWARD DIALING (DOD)
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A PBX or CENTREX feature that allows a station user to gain
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direct access to an exchange network. ++
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DROP
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The portion of outside telephone plant which extends from
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the telephone distribution cable to the subscriber's
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premises. ++
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DRY CIRCUIT (DC)
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A circuit which transmits voice signals and carries no
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direct current. ++
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DUAL TONE MULTI-FREQUENCY (DTMF)
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Also known as Touch-Tone. A type of signaling which emits
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two distinct frequencies for each indicated digit. ++
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DUPLEX
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Simultaneous two-way independent transmission. ++
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DUPLEX SIGNALING (DS)
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A long-range bidirectional signaling method using paths
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derived from transmission cable pairs. It is based on a
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balanced and symmetrical circuit that is identical at both
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ends. This circuit presents an E&M lead interface to
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connecting circuits. ++
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ECHO
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A signal that has been reflected or otherwise returned with
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sufficient magnitude and delay to be perceived by the
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speaker. ++
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ECHO RETURN LOSS (ERL)
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The loss which must be in the echo path to reduce echo to a
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tolerable amount. ++
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ECHO SUPPRESSOR
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A device which detects speech signals transmitted in either
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direction on a four-wire circuit, and introduces loss in the
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direction of transmission. ++
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EITHER END HOP OFF (EEHO)
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In private networks, a switch program that allows a call
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destined for an off-net location to be placed into the
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public network at either the closest switch to the
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origination or to the destination. The choice is usually by
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time of day. Uses either Head End Hop Off or Tail End Hop
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Off. ++
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ELECTRONIC KEY TELEPHONE SETS (EKTS)
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A generic term indicating key telephones with built-in
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microprocessors which allow access to PBX-like features as
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well as access to multiple CO lines, using 2 to 4 pair
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wiring. ++
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ELECTRONIC SWITCH (ESS)
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Modern programmable switch (often denoted ESS, for
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Electronic Switching System) used in most BOC telephone
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companies, many independent telephone companies, and by
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virtually all new long distance companies. Completely solid
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state electronics, as opposed to older electro-mechanical
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switches. ++
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ELECTRONIC SWITCHING SYSTEM (ESS)
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Used as a station instrument on a PBX. Also a Bell System
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term for electronic exchange switching equipment. ++
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ELECTRONIC TANDEM NETWORK (ETN)
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(1) A private network automatically and electronically
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connecting the calling office to the called office through
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Tandem-Tie Trunks. The network switches also function as
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PBXs. (2) An AT&T product name. (3) Used as a generic term
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for a PBX base network. ++
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ENHANCED PRIVATE SWITCHED COMMUNICATIONS SERVICE (EPSCS)
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A private network utilizing Bell provided equipment located
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in the central office and dedicated to a specific customer. ++
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E&M LEADS
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A pair of leads which carry signals between trunk equipment
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and separate signaling equipment unit. The M lead transmits
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battery or ground signals to the signaling equipment, and
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the E lead receives open or ground signals from the
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signaling equipment. ++
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E&M SIGNALING
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An arrangement whereby signaling between a trunk circuit and
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an associated signaling unit is effected over two leads
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providing full-time, 2-way, 2-level supervision. ++
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ENTERPRISE NUMBER
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A unique telephone exchange number that permits the called
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party to be automatically billed for incoming calls. ++
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EQUAL ACCESS
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Reprogramming of Local Exchange Company (LEC) switches to
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allow other long distance companies besides AT&T to be the
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"1+" primary long distance company for users of long
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distance (by creating a new type of Feature Group access
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circuit, FGD). Also provides "10-XXX" dialing for secondary
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and casual calling, generates true hardware Answer
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Supervision when calls are terminated over FGD circuits, and
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provides ANI (Automatic Number Identification) on
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originating calls. ++
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EQUALIZATION
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The procedure of compensating for fluctuation in circuit
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amplitude, delay, or distortion. ++
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ERLANG
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A unit of traffic intensity. One Erlang is the intensity at
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which one traffic path would be continuously occupied, e. g.
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one call per hour. ++
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ERLANG B TABLE
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A widely used table derived from a mathematical formula
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which allows the determination of the traffic capacity of a
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given group of circuits. ++
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EXCHANGE
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A telephone switching center. ++
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EXCHANGE NETWORK FACILITIES FOR INTERSTATE ACCESS (ENFIA)
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AT&T's pricing arrangement for local loops offered to OCCs
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for connecting the OCC's network to the local telephone
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company's central office. ++
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EXTENDED AREA SERVICE (EAS)
|
|
Adding expanded local calling areas to a caller's basic
|
|
local calling area for a (generally) small additional
|
|
monthly fee. The EAS local calls can be either free (after
|
|
a small additional monthly fee is paid) or at a cost of
|
|
reduced per call charges. ++
|
|
|
|
FACILITIES
|
|
Typically refers to transmission lines or circuits, or long
|
|
distance services. A caller's facilities are the circuits
|
|
available to make calls. ++
|
|
|
|
FACSIMILE (FAX)
|
|
The transmission of pictures, maps or other documents via
|
|
communications circuits using a device which scans the
|
|
original document, transforms the image into coded signals
|
|
and reproduces the original document at a distant point. ++
|
|
|
|
FEATURE GROUP A (FGA)
|
|
Line-side originating and terminating LATA access for which
|
|
an originating subscriber dials an assigned telephone number
|
|
that connects to a specific IC. The IC returns a tone to
|
|
signal the caller to input additional tone-generated digits
|
|
of the called number. ++
|
|
|
|
FEATURE GROUP B (FGB)
|
|
Trunk-side originating and terminating LATA access for which
|
|
an originating subscriber dials a 950-WXXX number (where
|
|
W=0,1 and XXX is the Carrier Access Code), which is
|
|
translated to a specified XXX carrier trunk group. Optional
|
|
rotary dial service and ANI may be available. ++
|
|
|
|
FEATURE GROUP C (FGC)
|
|
Trunk-side LATA access for AT&T, generally, on a direct
|
|
basis between each EO and an AT&T switching system. ++
|
|
|
|
FEATURE GROUP D (FGD)
|
|
Also referred to as "Equal Access," Feature Group D is
|
|
trunk-side LATA access affording call supervision to an IC,
|
|
a uniform access code (10XXX), optional calling-party
|
|
identification, recording of access-charge billing details,
|
|
and presubscription to a customer-specified IC. ++
|
|
|
|
FEDERAL COMMUNICATIONS COMMISSION (FCC)
|
|
The government agency established by the Communications Act
|
|
of 1934 which regulates the interstate communications
|
|
industry. ++
|
|
|
|
FIBER OPTICS
|
|
High speed transmission using light to send images (in
|
|
telecommunications: voice or data) through a flexible
|
|
bundle of glass fibers. ++
|
|
|
|
FOUR WIRE CIRCUITS
|
|
Circuits which use two separate one-way transmission paths
|
|
of two wires each, as opposed to regular local lines which
|
|
usually only have two wires to carry conversations in both
|
|
directions. One set of wires carries conversation in one
|
|
direction, the other in the opposite direction. ++
|
|
|
|
FREQUENCY
|
|
The number of complete cycles per unit of time. ++
|
|
|
|
FREQUENCY DIVISION MULTIPLEXING (FDM) The division of an
|
|
available frequency range (bandwidth) into various
|
|
subdivisions, each having enough bandwidth to carry one
|
|
voice or data channel. ++
|
|
|
|
FREQUENCY RESPONSE (FR)
|
|
The reaction of frequencies to the circuit components. ++
|
|
|
|
FULL DUPLEX (FD)
|
|
A circuit which allows transmission of a message in both
|
|
directions at the same time.
|
|
Synonym: 4-wire. ++
|
|
|
|
FULL PERIOD (FP)
|
|
Relates to private line service, which is rented for the
|
|
exclusive use of a single customer for an entire month. ++
|
|
|
|
FX (FOREIGN EXCHANGE) SERVICE (FX)
|
|
A service which allows a customer to appear to have a local
|
|
presence in a distant part of town or, a different town
|
|
altogether, by connecting his/her phone directly to a local
|
|
business line in a part of town with a different exchange
|
|
than his/her local calling area over a leased private line,
|
|
or to a local telco in a distant town through long haul
|
|
private lines purchased from a long distance carrier. ++
|
|
|
|
GRADE OF SERVICE (GS)
|
|
The probability of a call being blocked by busy trunks,
|
|
expressed as a decimal fraction, and usually meaning the
|
|
busy-hour probability. ++
|
|
|
|
GROUP
|
|
12 circuits processed as a unit in a carrier system. ++
|
|
|
|
HALF DUPLEX (HD)
|
|
A circuit for transmitting or receiving signals in one
|
|
direction at a time. ++
|
|
|
|
HARDWIRE
|
|
To wire or cable directly between units of equipment. ++
|
|
|
|
HARMONIC
|
|
The full multiple of a base frequency. ++
|
|
|
|
HARMONIC DISTORTION (HD)
|
|
The ratio, expressed in decibels, of the power at the
|
|
fundamental frequency, to the power of a harmonic of that
|
|
fundamental. ++
|
|
|
|
HEAD END HOP OFF (HEHO)
|
|
A method of traffic engineering whereby calls are completed
|
|
by using long distance facilities directly off the switch
|
|
that serves that location. ++
|
|
|
|
HERTZ (HZ)
|
|
International standard unit of frequency. Replaces, and is
|
|
identical to, the order unit "Cycles-per-second. ++"
|
|
|
|
HOMING
|
|
Returning to the starting position, as in a rotary stepping
|
|
switch. ++
|
|
|
|
HOOKSWITCH
|
|
The device on which the telephone receiver hangs or on which
|
|
a telephone handset hangs or rests when not in use. The
|
|
weight of the receiver or handset operates a switch which
|
|
opens the telephone circuit, leaving only the bell connected
|
|
to the line. ++
|
|
|
|
HOT-CUT
|
|
Virtually instantaneous replacement of one line with
|
|
another. ++
|
|
|
|
HYBRID
|
|
An electronic circuit which performs the wire conversions
|
|
necessary for the connection of a local loop with a long-
|
|
haul facility. ++
|
|
|
|
INTERCEPT
|
|
To stop a telephone call directed to an improper telephone
|
|
number, and redirect that call to an operator or a
|
|
recording. ++
|
|
|
|
INTERCONNECT (IC)
|
|
(1) The arrangement that permits the connection of
|
|
customer's telecommunications equipment to a communications
|
|
common carrier network. (2) The industry name for
|
|
manufacturers, excluding the Bell system, which provide
|
|
telephone equipment for the customer premises. ++
|
|
|
|
INTER-EXCHANGE MILEAGE (IXC)
|
|
The airline mileage between two cities.
|
|
Synonym: Long Haul Mileage. ++
|
|
|
|
INTEREXCHANGE PLANT (IP)
|
|
The facilities between the subscriber switching center and
|
|
another switching center. ++
|
|
|
|
INTERFACE
|
|
The junction or point of interconnection between two systems
|
|
or equipment having different characteristics. ++
|
|
|
|
INTERFERENCE
|
|
Any unwanted noise or crosstalk on a communications circuit
|
|
which acts to reduce the intelligibility of the desired
|
|
signal or speech. ++
|
|
|
|
INTER-MACHINE TRUNK (IMT)
|
|
A circuit which connects two automatic switching centers. ++
|
|
|
|
INTER-OFFICE TRUNK (IOT)
|
|
A direct trunk between local exchange offices. ++
|
|
|
|
INTERNATIONAL RECORD CARRIER (IRC)
|
|
Carriers providing international telecommunications
|
|
services, including voice, telex, and data communications. ++
|
|
|
|
INTERSTATE
|
|
Any connection made between two states. ++
|
|
|
|
INTRASTATE
|
|
Any connection made that remains within the boundaries of a
|
|
single state. ++
|
|
|
|
JITTER
|
|
Short term instability of the amplitude and/or phase of a
|
|
signal. Commonly called PHASE JITTER. ++
|
|
|
|
KEYSET
|
|
A telephone instrument having an appearance of two or more
|
|
telephone lines which can be accessed by depressing a button
|
|
(key) on the face of the set. ++
|
|
|
|
KEY SYSTEM
|
|
The equipment utilized to provide the features associated
|
|
with key sets, including keysets, multipair cable, key
|
|
service unit, distribution frames. ++
|
|
|
|
LEASED LINES (LL)
|
|
Any circuit or combination of circuits designated to be at
|
|
the exclusive disposal of a given subscriber.
|
|
Synonym: Private line; Full Period Line. ++
|
|
|
|
LEAST COST ROUTING (LCR)
|
|
A method of automatically selecting the least costly
|
|
facility for transmission of a call.
|
|
Synonym: Most Economical Route Selection (MERS); Automatic
|
|
Route Selection; Flexible Route Selection. ++
|
|
|
|
LEVEL
|
|
An expression of the relative signal strength at a point in
|
|
a communications circuit compared to a standard. ++
|
|
|
|
LOADING
|
|
A system for adding regularly spaced inductance units to a
|
|
circuit to improve its transmission characteristics. ++
|
|
|
|
LOCAL ACCESS AND TRANSPORT AREA (LATA)
|
|
A geographic area (called "exchange" or "exchange area" in
|
|
the MFJ) within each BOC's franchised area that has been
|
|
established by a BOC in accordance with the provisions of
|
|
the MFJ for the purpose of defining the territory within
|
|
which a BOC may offer its telecommunications services. ++
|
|
|
|
LOCAL AREA NETWORK (LAN)
|
|
Intraoffice communication system usually used to provide
|
|
data transmission in addition to voice transmission. ++
|
|
|
|
LOCAL EXCHANGE CARRIER (LEC)
|
|
A local telephone company, either one of the Bell Operating
|
|
Companies or one of the 1400+ independent local telephone
|
|
companies. ++
|
|
|
|
LOCAL LOOP
|
|
The local connection between the end user and the Class 5
|
|
central office. ++
|
|
|
|
LONG HAUL
|
|
Circuits spanning considerable distances. ++
|
|
|
|
LOOP BACK
|
|
A method of performing transmission tests on a circuit not
|
|
requiring the assistance of personnel at the distant end. ++
|
|
|
|
LOOP SIGNALING
|
|
Any of the three signaling methods which use the metallic
|
|
loop formed by the trunk conductors and the terminating
|
|
equipment bridges. ++
|
|
|
|
MAIN DISTRIBUTION FRAME (MDF)
|
|
The point where outside plant cables terminate and from
|
|
which they cross connect to terminal or central office line
|
|
equipment. ++
|
|
|
|
MAIN PBX (PBX)
|
|
A PBX directly connected to a tandem switch via an access
|
|
trunk group. ++
|
|
|
|
MANUAL TIE LINE (TIE LINE)
|
|
A tie line which requires the assistance of an attendant at
|
|
both ends of the circuit in order to complete a call. ++
|
|
|
|
MASTER GROUP (MG)
|
|
240 circuits processed as a unit in a carrier system. ++
|
|
|
|
MESSAGE TELEPHONE SERVICE (MTS)
|
|
AT&T's tariffed pricing name for long distance telephone
|
|
calls. ++
|
|
|
|
MESSAGE UNIT (MU)
|
|
A local toll rate calling plan which is time and distance
|
|
sensitive. ++
|
|
|
|
MICROWAVE (M/W)
|
|
Radio transmission using very short lengths, corresponding
|
|
to a frequency of 1,000 megahertz or greater. ++
|
|
Synonym: Microwave Radio. ++
|
|
|
|
MICROWAVE RADIO
|
|
|
|
Synonym: Microwave. ++
|
|
|
|
MODEM
|
|
A device which modulates and demodulates signals on a
|
|
carrier frequency and allows the interface of digital
|
|
terminals with analog carrier systems. ++
|
|
|
|
MODIFIED FINAL JUDGEMENT (MFJ)
|
|
The agreement between the U.S. Department of Justice and
|
|
AT&T governing the breakup of the pre-Divestiture Bell
|
|
System into AT&T and 22 Bell Operating Companies and other
|
|
entities. On August 26, 1982, U. S. District Court Judge
|
|
Harold Greene accepted, with modifications, an AT&T/Justice
|
|
Department settlement terminating the government's 1974
|
|
antitrust suit against AT&T. Judge Greene's decree did away
|
|
with the provisions of the 1956 consent decree that had kept
|
|
AT&T out of competitive, unregulated ventures. ++
|
|
|
|
MODULATION
|
|
Alterations in the characteristics of carrier waves. Usually
|
|
impressed on the amplitude and/or the frequency. ++
|
|
|
|
MONITORING DEVICE
|
|
Records data on calls placed through a company's telephone
|
|
system: number called, length of calls, calling location. ++
|
|
|
|
MOST ECONOMICAL ROUTE SELECTION (MERS)
|
|
|
|
Synonym: Least Cost Routing. ++
|
|
|
|
MULTIPLEXING (MP)
|
|
The act of combining a number of individual message circuits
|
|
for transmission over a common path. Two methods are used:
|
|
(1) frequency division, and (2) time division. ++
|
|
|
|
NETWORK
|
|
A collection of switches connected to one another by
|
|
transmission facilities.
|
|
|
|
NETWORK NUMBERING EXCHANGE (NXX)
|
|
The three digit location code representing the central
|
|
office. "N" may be any number between "2" and "9" and "X"
|
|
may be any number. ++
|
|
|
|
NETWORK TRUNKS
|
|
Circuits connecting switching centers. ++
|
|
|
|
NNX CODES
|
|
The 3-digit code used historically for local Exchange Codes.
|
|
"N" can be any number from 0 to 2, "X" can be any digit.
|
|
The current numbering plan allows for more variation in
|
|
assigning Exchange Codes, and under it Exchange Codes are
|
|
commonly referred to as "NXXs." ++
|
|
|
|
NODE
|
|
A major switching center of a network. ++
|
|
|
|
NON-BLOCKING
|
|
A switching network having a sufficient number of paths such
|
|
that a subscriber originating a call can always reach any
|
|
other idle subscriber without encountering a busy. ++
|
|
|
|
NUMBERING PLAN AREA (NPA) (NANP) (AREA)
|
|
A geographical division within which no two telephones will
|
|
have the same 7 digit number. "N" is any number between "2"
|
|
and "9"; "P" is always "1" or "0"; and "A" is any number
|
|
excluding "0". Commonly referred to as "area code." ++
|
|
|
|
NXX CODES (NNX)
|
|
The current general configuration for Exchange Codes within
|
|
each Area Code. See also: "NNX Codes" ++
|
|
|
|
OFFERED TRAFFIC
|
|
The number of call attempts in any specified period of time. ++
|
|
|
|
OFF HOOK
|
|
The condition which results when a telephone is lifted from
|
|
its mounting, allowing the hookswitch to operate. ++
|
|
|
|
OFF-NETWORK ACCESS LINE (ONAL)
|
|
A local exchange (Feature Group access), Foreign Exchange,
|
|
or WATS line connecting both incoming and outgoing traffic
|
|
from a long distance company's network to the public
|
|
switched network. Generally a circuit leased by a long
|
|
distance carrier to be used by many customers not hooked
|
|
directly into the long distance carrier's network. ++
|
|
|
|
OFF NETWORK CALLING
|
|
Telephone calls through a private switching system and
|
|
transmission network which extend to the public telephone
|
|
system. ++
|
|
|
|
OFF PREMISES EXTENSION (OPX)
|
|
An extension telephone or keyset that is geographically
|
|
separated from its associated PBX. ++
|
|
|
|
ON HOOK
|
|
The condition which results when a telephone handset is
|
|
placed on its mounting, which causes the hook-switch to open
|
|
its contacts. ++
|
|
|
|
ON NETWORK CALLING
|
|
A term used to describe a call that originates and
|
|
terminates on a private network. ++
|
|
|
|
OPERATOR ASSISTED CALLS (OAC) (AOS)
|
|
Non-DDD calls requiring manual intervention. ++
|
|
|
|
ORIGINATING OFFICE
|
|
The central office that serves the calling party. ++
|
|
|
|
OTHER COMMON CARRIER (OCC) (AOS)
|
|
A long distance company other than AT&T having many of its
|
|
own long distance circuits, either owned or leased. Some
|
|
people use OCC to refer to all AT&T long distance
|
|
competitors, including resellers, but this is not
|
|
technically correct. ++
|
|
|
|
OUT-OF-BAND
|
|
Any frequency outside the band used for voice frequencies. ++
|
|
|
|
OUT-OF-BAND SIGNALING
|
|
Use of narrow band filters to place the voice signal on a
|
|
carrier channel below 3,400 CPS, reserving the 3,400 - 3,700
|
|
CPS band for supervisory signals. ++
|
|
|
|
OVERBUILD
|
|
Adding radio capacity to a telecommunications network. ++
|
|
|
|
OVERFLOW
|
|
Switching equipment which operates when the traffic load
|
|
exceeds the capacity of the regular equipment. ++
|
|
|
|
PAD
|
|
A non-adjustable resistance network used to insert
|
|
transmission loss into a circuit. ++
|
|
|
|
PHASE JITTER
|
|
SEE Jitter ++
|
|
|
|
POINT OF PRESENCE (POP)
|
|
A physical location within a LATA at which an IC establishes
|
|
itself for the purpose of obtaining LATA access and to which
|
|
the BOC provides access services. ++
|
|
|
|
POINT-TO-POINT
|
|
A communications circuit between two terminations which does
|
|
not connect with a public telephone system. ++
|
|
|
|
PORT
|
|
Entrance or access point to a computer, multiplexor device
|
|
or network where signals may be supplied, extracted or
|
|
observed. ++
|
|
|
|
POSTAL TELEPHONE AND TELEPGRAPH (PTT)
|
|
Foreign government agencies responsible for regulating
|
|
communications. ++
|
|
|
|
PRIMARY AREA
|
|
A customer's local telphone calling area. ++
|
|
|
|
PRIMARY INTEREXCHANGE CARRIER (PIC)
|
|
The IC designated by a customer to provide inter-LATA
|
|
service automatically without requiring the customer to dial
|
|
an access code for that carrier. ++
|
|
|
|
PRIMARY ROUTING POINT (PRP)
|
|
The switch designated as the control point for a longhaul
|
|
telephone call. ++
|
|
|
|
PRIVATE BRANCH EXCHANGE (PBX)
|
|
A private phone system (switch) used by medium and large
|
|
companies which is connected to the public telephone network
|
|
(local telco) and performs a variety of in-house routing and
|
|
switching. User usually dial "9" to get outside system to
|
|
the local lines. ++
|
|
|
|
PRIVATE LINE (PL)
|
|
A full-time leased line directly connecting two points, used
|
|
soley by purchaser. The most common form is a tie line
|
|
connecting two pieces of a user's own phone equipment - flat
|
|
rate billing, not usage sensitive. ++
|
|
|
|
PRIVATE USE NETWORK
|
|
Two or more private line channels contracted for by a
|
|
customer and restricted for use by that customer only. ++
|
|
|
|
PUBLIC SWITCHED NETWORK (PSN)
|
|
The pre-Divestiture nationwide network maintained by AT&T
|
|
and the independent telephone companies which provides
|
|
nationwide, unrestricted telephone service. ++
|
|
|
|
PUBLIC UTILITY COMMISION (PUC)/PUBLIC SERVICE COMMISSION
|
|
(PSC)
|
|
The state commissions regulating intrastate communications. ++
|
|
|
|
PULSE CODE MODULATION (PCM)
|
|
The form of modulation in which the information signals are
|
|
sampled at regular intervals and a series of pulses in coded
|
|
form are transmitted representing the amplitude of the
|
|
information signal at that time. ++
|
|
|
|
PULSE-LINK REPEATER
|
|
Connects one E&M signaling circuit directly to another. ++
|
|
|
|
PULSE MODULATION (PAM) (PWM) (PPM) (PCM)
|
|
The modulation of a series of pulses which
|
|
represents information-bearing signals. Typical methods
|
|
involve modifying the amplitude (PAM), width or duration
|
|
(PWM) or position (PPM). Pulse Code Modulation (PCM) is the
|
|
most common modulation technique involved in telephone work. ++
|
|
|
|
PUSH BUTTON DIALING
|
|
|
|
Synonym: Dual Tone Multi-Frequency. ++
|
|
|
|
QUEUE
|
|
A temporary delay in providing service caused by the
|
|
inability of the system provided to handle the number of
|
|
messages or calls attempted. ++
|
|
|
|
RADIO COMMON CARRIER (RCC)
|
|
A communications common carrier that provides radio paging
|
|
and mobile telephone services to the public. ++
|
|
|
|
RATE CENTER (RC)
|
|
A specified geographic location used by the telephone
|
|
company to determine interchange mileage for rate
|
|
determination purposes. ++
|
|
|
|
REDUNDANCY
|
|
Duplicate equipment that is provided to minimize the effect
|
|
of failures or equipment breakdowns. ++
|
|
|
|
REGENERATION
|
|
The process of receiving distorted signal pulses and from
|
|
them recreating new pulses at the correct repetition rate,
|
|
pulse amplitude, and pulse width. ++
|
|
|
|
RE-HOMING
|
|
A major network change which involves moving customer
|
|
services from one switching center to another and
|
|
establishing the necessary trunking facilities to do so. ++
|
|
|
|
REMOTE ACCESS (RA)
|
|
The ability of transmission points to gain access to a
|
|
computer which is at a different location. ++
|
|
|
|
REPEATER
|
|
An electronic device used to amplify signals which have
|
|
become too weak. ++
|
|
|
|
REPEATING COIL (RC)
|
|
The telephone industry's term for a voice-frequency
|
|
transformer. ++
|
|
|
|
RESELLER (AOS) (OCC)
|
|
A long distance company that purchases large amounts of
|
|
transmission capacity or calls from other carriers and
|
|
resells it to smaller users. ++
|
|
|
|
RESTORATION
|
|
The re-establishment of service by rerouting, substitution
|
|
of component parts, or as otherwise determined. ++
|
|
|
|
RETARD COIL
|
|
A coil having a large inductance which retards sudden
|
|
changes of the current flowing through its winding. ++
|
|
|
|
RINGBACK TONE (RT}
|
|
|
|
Synonym: Audible Ringing Tone. ++
|
|
|
|
RINGDOWN
|
|
A circuit or method of signaling where the incoming signal
|
|
is actuated by alternating current over the circuit. ++
|
|
|
|
ROUTE DIVERSITY
|
|
Two (or more) private line channels (circuits) furnished
|
|
partially or entirely over two physically separate routes.
|
|
Serves to prevent total loss of service if one cable gets
|
|
cut or goes out. ++
|
|
|
|
ROUTE OPTIMIZATION
|
|
|
|
Synonym: Least Cost Routing. ++
|
|
|
|
ROTARY HUNT
|
|
An arrangement which allows calls placed to seek out an idle
|
|
circuit in a prearranged multi-circuit group and find the
|
|
next open line to establish a through circuit. ++
|
|
|
|
SATELLITE RELAY
|
|
An active or passive repeater in geosynchronous orbit around
|
|
the Earth which amplifies the signal it receives before
|
|
transmitting it back to earth. ++
|
|
|
|
SELECTIVE CALLING
|
|
The ability of a transmitting station to specify by the use
|
|
of assigned codes which of several stations is to receive a
|
|
message. ++
|
|
|
|
SERVICE AND EQUIPMENT RECORD (SAER)
|
|
A list of equipment billed to customer by type, quantity,
|
|
monthly charge, location and billing dates. ++
|
|
|
|
SF SIGNALING (SINGLE-FREQUENCY) (SFS)
|
|
A signaling system which uses a 2,600 Hz in-band signal on
|
|
the voice path. The tone is on in the idle condition,
|
|
pulsed for dialing, and off when the circuit is in use. ++
|
|
|
|
SHORT HAUL
|
|
Circuits designed for use over distances of 10-200 miles. ++
|
|
|
|
SIGNALING
|
|
The process of transferring information between two parts of
|
|
a telephone network to control the establishment of
|
|
communications between long distance carrier terminal
|
|
points, and customer equipment required for voice grade
|
|
dedicated circuits. ++
|
|
|
|
SIGNALING CONVERTER (SC)
|
|
A device with input and output signals that contain the same
|
|
information but employ different electrical systems for
|
|
transmitting that information. Used at the terminal of a
|
|
trunk to convert the equipment signals to the system used on
|
|
the trunk. Examples are: (1) ring down to SF, (2) E&M to
|
|
SF. ++
|
|
|
|
SIGNALING, IN-BAND
|
|
A type of signaling using an AC signal (usually 2,600 Hz)
|
|
within the normal voice band. This signal can be
|
|
transmitted from end to end of a long voice circuit without
|
|
an intermediate signaling equipment. Since the signaling is
|
|
audible, the signaling equipment must be arranged for "tone
|
|
on when idle" operation. ++
|
|
|
|
SIGNAL TO NOISE RATIO (SNR)
|
|
Ratio of the signal power to the noise power in a specified
|
|
bandwidth, usually expressed in db. ++
|
|
|
|
SIMPLEX (SX) SIGNALING A signaling path over a dry talking
|
|
circuit which uses the two sides of the circuit in parallel,
|
|
derived by connecting the midpoints of repeating coils or
|
|
retardation coils which are across the circuit. ++
|
|
|
|
SINGLE SIDEBAND RADIO (SSB)
|
|
A form of amplitude modulation of a radio signal in which
|
|
only one of the two sidebands is transmitted. ++ Either of the
|
|
two sidebands may be transmitted, and the carrier may be
|
|
transmitted, reduced or suppressed. ++
|
|
|
|
SINGING
|
|
A continued whistle or howl in an amplified telephone
|
|
circuit. It occurs when the sum of the repeater gains
|
|
exceeds the sum of the circuit losses. ++
|
|
|
|
SOFTWARE DEFINED NETWORK (SDN)
|
|
A switched long distance service for very large users with
|
|
multiple locations. Instead of putting together their own
|
|
network, large users can get special usage rates for calls
|
|
made on regular long distance company switched long distance
|
|
services.
|
|
Synonym: Virtual Private Network. ++
|
|
|
|
SPECIAL GRADE NETWORK TRUNK (SGNT)
|
|
A trunk specially conditioned by providing amplitude and
|
|
delay equilization for the purpose of handling special
|
|
services such as medium-speed data (600 to 2400 BPS). ++
|
|
|
|
SPECIALIZED COMMON CARRIER (SCC)
|
|
|
|
Synonym: Other Common Carrier. ++
|
|
|
|
SPEED NUMBER
|
|
A one, three, or four digit number that replaces a seven or
|
|
ten digit telephone number. These numbers are programmed
|
|
into the switch in the carrier's office or in a PBX. ++
|
|
|
|
STATION
|
|
Any customer location on a network capable of sending or
|
|
receiving messages or calls. ++
|
|
|
|
STATION MESSAGE DETAIL RECORDING (SMDR)
|
|
A computer generated report showing internal usage on a
|
|
telephone system. Usually including extension number, trunk
|
|
number used, phone number dialed, time of call, duration and
|
|
operator involvement. ++
|
|
|
|
STORE-AND-FORWARD
|
|
A technique in which a message is received from the
|
|
originator and held in storage until a circuit to the
|
|
addressee becomes available. ++
|
|
|
|
STORED PROGRAM CONTROL (SPC)
|
|
A system whereby the instructions are placed in the memory
|
|
of a commoncontrolled switching unit and to which it refers
|
|
while processing a call for instructions regarding class
|
|
marks, code conversions, routing, as well as for trouble
|
|
analysis. ++
|
|
|
|
SUPERGROUP (SG)
|
|
60 circuits processed as a unit in a carrier system. ++
|
|
|
|
SUPERMASTERGROUP (SMG)
|
|
600 circuits processed as a unit in a carrier system. ++
|
|
|
|
SUPERVISION (AS)
|
|
|
|
Synonym: Answer Supervision. ++
|
|
|
|
SUPERVISORY SIGNALS (SS) (AS)
|
|
A signal, such as "on-hook" or "off-hook," which indicates
|
|
whether a circuit or line is in use. ++
|
|
|
|
SWITCH
|
|
Equipment used to interconnect lines and trunks. ++
|
|
|
|
SWITCHED ACCESS (SA)
|
|
Connection between caller's phone system and switch of
|
|
chosen long distance carrier when a regular long distance
|
|
call using regular local lines is made. Also the connection
|
|
between the switch of caller's long distance carrier in the
|
|
distant city and the phone being called. ++
|
|
|
|
SWITCH HOOK
|
|
|
|
Synonym: Hookswitch. ++
|
|
|
|
SWITCHING
|
|
The operations involved in interconnecting circuits in order
|
|
to establish communications. ++
|
|
|
|
SWITCHING CENTER (SC) (CO)
|
|
A location at which telephone traffic, either local or toll,
|
|
is switched or connected from one circuit or line to
|
|
another. ++
|
|
|
|
SWITCHING OFFICE (SO) (CO)
|
|
A telephone company office which contains a switch. ++
|
|
|
|
T-1 (T-1) (T1)
|
|
24 voice channels digitized at 64,000 bps, combined into a
|
|
single 1. ++544 Mbps digital stream (8,000 bps signaling), and
|
|
carried over two pairs of regular copper telephone wires. ++
|
|
Used primarily by telephone companies until 1983. Now used
|
|
for dedicated local access to long distance facilities,
|
|
long-haul private lines, and for regular local service.
|
|
Today, most any 1.544 Mbps digital stream is called T-1,
|
|
regardless of its makeup or what the transmission medium is. ++
|
|
|
|
T-CARRIER (T-1)
|
|
A time-division, pulse-code modulation, voice carrier used
|
|
on exchange cable to provide short-haul trunks. ++
|
|
|
|
TAIL END HOP OFF (TEHO)
|
|
In a private network, a call which is carried over flat rate
|
|
facilities (Intermachine Trunks or IMT) to the closest
|
|
switch node to the destination of the call, and then
|
|
connected into the public network as a local call. ++
|
|
|
|
TANDEM
|
|
A switching arrangement in which the trunk from the calling
|
|
office is connected to a trunk to the called office through
|
|
an intermediate point. ++
|
|
|
|
TANDEM SWITCHING SYSTEM (TTTN) (TSS)
|
|
|
|
Synonym: Tandem Tie Trunk Network. ++
|
|
|
|
TANDEM TIE TRUNK NETWORK (TTTN)
|
|
A serving arrangement which permits sequential connection of
|
|
tie trunks between PBX/CENTREX locations by utilizing tandem
|
|
operation. ++
|
|
|
|
TANDEM TRUNKING
|
|
Trunks which connect two or more switches together. ++
|
|
|
|
TARIFF
|
|
The published rates, regulations, and descriptions governing
|
|
the provisions of communications service. ++
|
|
|
|
TELCO (BOC)
|
|
Local telephone company. ++
|
|
|
|
TELECOMMUNICATIONS
|
|
The transmission of voice and/or data through a medium by
|
|
means of electrical impulses and includes all aspects of
|
|
transmitting information. ++
|
|
|
|
TELEGRAPH (TELEX) (TWX)
|
|
A system employing the interruption of, or change in, the
|
|
polarity of DC current signaling to convey coded
|
|
information. ++
|
|
|
|
TELEPHONE
|
|
A device which converts acoustical (sound) energy into
|
|
electrical energy for transmission to a distant point. ++
|
|
|
|
TELETYPEWRITER (TTY) (TWX) (TELEX)
|
|
A machine used to transmit and/or receive communications on
|
|
printed page and/or tape. ++
|
|
|
|
TERMINAL
|
|
A point at which information can enter or leave a
|
|
communications network. ++
|
|
|
|
TERMINAL EQUIPMENT (TE)
|
|
Devices, apparatus and their associated interfaces used to
|
|
forward information to a local customer or distant terminal. ++
|
|
|
|
TERMINATION
|
|
(1) An item that is connected to the terminal of a circuit
|
|
or equipment. (2) An impedance connected to the end of a
|
|
circuit being tested. (3) The points on a switching network
|
|
to which a trunk or line may be attached. ++
|
|
|
|
TIE-LINE
|
|
A private leased line linking two phones or phone systems
|
|
directly. Can ring distant phone automatically when
|
|
telephone is lifted from its mounting, or when a short code
|
|
is dialed. ++
|
|
|
|
TIME DIVISION MULTIPLEXING (TDM)
|
|
Equipment which enables the transmitting of a number of
|
|
signals over a single common path by transmitting them
|
|
sequentially at different instants of time. ++
|
|
|
|
TOLL CALL
|
|
Any call to a point outside the local service area. ++
|
|
|
|
TOLL CENTER (TC) (CO)
|
|
A central office where operators (human or mechanical) are
|
|
present to assist in completing incoming toll calls. ++
|
|
|
|
TOLL OFFICE (TO) (TC)
|
|
A center for the switching of toll calls. ++
|
|
|
|
TOLL PLANT (TP) (TO)
|
|
The facilities that connect toll offices throughout the
|
|
country. ++
|
|
|
|
TOLL RESTRICTION (TR)
|
|
A restriction in outgoing trunks which counts the first
|
|
three digits dialed and diverts calls to forbidden codes
|
|
either to a busy tone, to the operator, or to a recorded
|
|
announcement. ++
|
|
|
|
TOUCH-TONE ADAPTOR (TT)
|
|
A device that can be connected to a rotary dial telephone to
|
|
allow for DTMF signaling. ++
|
|
|
|
TRAFFIC
|
|
Calls being sent and received over a communications network. ++
|
|
|
|
TRAFFIC MEASUREMENT AND RECORDING SYSTEMS (TMRS)
|
|
A computer generated report showing usage information of
|
|
telephone systems. Usually this includes trunk utilization,
|
|
outages, queueing time, and the need for additional common
|
|
equipment. ++
|
|
|
|
TRAFFIC SERVICE POSITION SYSTEM (TSPS)
|
|
A toll switchboard position configured as a push button
|
|
console. ++
|
|
|
|
TRANSMISSION (XMISSION) (XMIT)
|
|
The electrical transfer of a signal, message or other form
|
|
of data from one location to another without unacceptable
|
|
loss of information content due to attenuation, distortion,
|
|
or noise. ++
|
|
|
|
TRANSMISSION LEVEL (TL)
|
|
The level of power of a signal, normally 1,000 Hz, which
|
|
should be measured at a particular reference point. ++
|
|
|
|
TRANSMISSION SPEED (TS) (WPM) (BAUD) (BPS)
|
|
Number of pulses or bits transmitted in a given period of
|
|
time, usually expressed as Bits Per Second (BPS) or Words
|
|
Per Minute (WPM). ++
|
|
|
|
TRUNK
|
|
A telephone circuit or path between two switches, at least
|
|
one of which is usually a telephone company Central Office
|
|
or switching center. Regular local CO circuits are called
|
|
PBX trunks, because there is a switch at both ends of the
|
|
circuit. ++
|
|
|
|
TRUNK GROUP (TG)
|
|
An arrangement of communications channels into an identical
|
|
group. ++
|
|
|
|
TRUNK TYPE (TT)
|
|
Trunks that use the same type of equipment going to the same
|
|
terminating location. ++
|
|
|
|
TRUNK UTILIZATION REPORT (TUR)
|
|
A computer printout detailing the traffic use of a trunk. ++
|
|
|
|
TWO-WIRE CIRCUIT
|
|
(1) A channel for transmitting data in one direction at a
|
|
time. (2) A short distance channel using a single
|
|
send/receive pathway, usually 2 copper wires, connecting a
|
|
telephone to a switch. ++
|
|
|
|
TELETYPEWRITER EXCHANGE SERVICE (TWX) (TELEX) (TTY)
|
|
A service whereby a customer's leased teletypewriter is
|
|
connected to a "TWX" switchboard and from there connected
|
|
over regular toll circuits to a teletypewriter of any U.S.
|
|
customer who subscribes to a similar service. ++
|
|
|
|
UNIFORM CALL DISTRIBUTOR (UCD) (ACD)
|
|
A device located at the telephone office or in a PABX which
|
|
distributes incoming calls evenly among individuals. ++
|
|
|
|
UNIFORM SERVICE ORDER CODE (USOC)
|
|
The information in coded form for billing purposes by the
|
|
local telephone company pertaining to information on service
|
|
orders and service equipment records. ++
|
|
|
|
VALUE-ADDED NETWORK SERVICE (VANS)
|
|
A data transmission network which routes messages according
|
|
to available paths, assures that the message will be
|
|
received as it was sent, provides for user security, high
|
|
speed transmission and conferencing among terminals. ++
|
|
|
|
VIA NET LOSS (VNL)
|
|
The lowest loss in dB at which a trunk facility can be
|
|
operated considering limitations of echo, crosstalk, noise
|
|
and singing. ++
|
|
|
|
VOICE CONNECTING ARRANGEMENT (VCA)
|
|
An interface arrangement provided by the telephone company
|
|
to accomodate the connections of non-carrier provided voice
|
|
terminal equipment to the public switched telephone network. ++
|
|
|
|
VOICE FREQUENCY (VF)
|
|
Any of the frequencies in the band 300-3,400 Hz which must
|
|
be transmitted to reproduce the voice with reasonable
|
|
fidelity. ++
|
|
|
|
VOICE GRADE (VG)
|
|
An access line suitable for voice, low-speed data,
|
|
facsimile, or telegraph service. Generally, it has a
|
|
frequency range of about 300-3000 Hz. ++
|
|
|
|
VOICE GRADE FACILITY (VGF)
|
|
A circuit designed to DDD network standards which is
|
|
suitable for voice, low-speed data, facsimile, or telegraph
|
|
service. ++
|
|
|
|
WIDE AREA TELECOMMUNICATIONS SERVICE (WATS)
|
|
WATS permits customers to make (OUTWATS) or receive
|
|
(INWATS) long-distance calls and to have them billed on
|
|
a bulk rather than individual call basis. The service
|
|
is provided within selected service areas, or bands,
|
|
by means of special private access lines connected to
|
|
the pubic telephone network via WATS-equipped central
|
|
offices. A single access line permits inward or outward
|
|
service, but not both. ++
|
|
|
|
WIDEBAND (WB)
|
|
A term applied to facilities or circuits where bandwidths
|
|
are greater than that required for one voice channel. ++
|
|
|
|
WIRE CENTER (WC)
|
|
The physical structure that houses one or more central
|
|
office switching systems. ++
|
|
|
|
"0" or "0-" (AOS)
|
|
Zero minus dialing. Allows a caller to dial zero and
|
|
nothing else to get the Operator. ++
|
|
|
|
"0+" (AOS)
|
|
Zero plus dialing. An operator assisted long distance call
|
|
which is charged to the calling party. ++
|
|
|
|
"00+" or "00-" (OCC) (AOS)
|
|
Double zero dialing. Allows a caller to get an AT&T
|
|
Operator in areas in which dialing only one zero would
|
|
connect the caller with the local Operator because AT&T has
|
|
given Operators back to the local telephone company. ++
|
|
|
|
"1+" DIALING (IXC) (OCC) (AOS)
|
|
The capability to dial "1" plus the long distance number for
|
|
calls withing the North American Numbering Plan area.
|
|
Intra-LATA calls are carried by the local telephone company.
|
|
Inter-LATA calls are carried by the caller's primary
|
|
carrier, or by AT&T if equal access has not come to the
|
|
caller's area yet. ++
|
|
|
|
"10-XXX" DIALING (OCC) (AOS) (IXC)
|
|
The ability to send calls over a carrier other than a
|
|
caller's primary carrier by dialing "10-XXX" then "1+" the
|
|
long distance number, where "XXX" is the 3-digit Carrier
|
|
Code of the alternative long distance company (also called a
|
|
secondary carrier). Available only to Equal Access
|
|
customers. ++
|
|
|
|
800 SERVICE (800)
|
|
The ability of a caller to dial a long distance telephone
|
|
number without incurring a charge for the call, which is
|
|
paid for by the party offering the 800 number.
|
|
Synonym: Inward WATS service. ++
|
|
|
|
900 SERVICE (900) (976)
|
|
Allows callers to receive information from the service
|
|
provider via a recorded audio message, which can range from
|
|
60 seconds to a continuous live hookup, by calling a 900
|
|
number. This service can also be used to enable callers to
|
|
vote or "make a choice" by dialing one of two 900 numbers.
|
|
900 calls are typically billed to the caller at much
|
|
higher rates than regular calls. ++
|
|
|
|
976 NUMBERS (900) (976)
|
|
Service which allows callers to listen to recorded messages
|
|
such as horoscopes, 'adult' dialogue, stock market or sports
|
|
reports by calling 976-xxxx. The local telephone company
|
|
charges callers a fee which is split between the local
|
|
telephone company and the service provider. ++
|
|
|