470 lines
16 KiB
Plaintext
470 lines
16 KiB
Plaintext
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_ _ _______
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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 II (E - N)
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Typed and Edited by Knight Lightning
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===============================================================================
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- E -
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ECHO A signal that has been reflected or
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otherwise returned with sufficient
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magnitude and delay to be percieved by
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the speaker.
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ECHO RETURN LOSS (ERL) The loss which must be in the echo path
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to reduce echo to a tolerable amount.
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ECHO SUPRESSOR A device which detects speech signals
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transmitted in either direction on a
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four-way circuit, and introduces loss
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in the direction of transmission.
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EIGHT HUNDRED SERVICE (800) A commonly used reference for inward
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WATS service (See WATS, Inward).
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EITHER END HOP OFF (EEHO) Uses either Head Hop Off or Tail End Hop
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Off.
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ELECTRONIC DATA PROCESSING The use of electronic memories to store,
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up-date, read, and use information.
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ELECTRONIC KEY TELEPHONE SETS (EKTS) A generic term indicating key telephones
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with special buttons which are
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electronically programmed to access
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various PBX features.
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ELECTRONIC SWITCHING SYSTEM (ESS) A Bell System term for electronic
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exchange switching equipment.
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ELECTRONICALLY PROGRAMMABLE READ Memory which is initially programmed by
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ONLY MEMORY (EPROM) the manufacturer. Changes can be made
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to conform to the customer requirements
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at their premises.
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ELECTRONIC TANDEM NETWORK (ETN) 1. A private network automatically and
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electronically connecting the calling
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office to the called office through
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Tandem-Tie-Trunks. The network switches
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also function as PBX's. 2. An AT&T
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product name. 3. Used as a generic term
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a PBX base network.
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END OFFICE CONVERSATION When an end office offers equal access.
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ENHANCED PRIVATE SWITCHED A private network utilizing Bell
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COMMUNICATIONS SERVICE (EPSCS) provided equipment located in the
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central office and dedicated to a
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specific customer.
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E&M LEADS A pair of leads which carry signals
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between trunk equipment and separate
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signaling equipment unit. The M lead
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transmits battery or ground signals to
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the signaling equipment, and the E lead
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receives open or ground signals from the
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signaling equipment.
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E&M SIGNALING An arrangement whereby signaling between
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a trunk circuit and an associated
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signaling unit is effected over two
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leads providing full-time, 2-way,
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2-level supervision.
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ENTERPRISE NUMBER A unique telephone exchange number that
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permits the called party to be
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automatically billed for the incoming
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calls.
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Synonym: "Toll Free Number;" INWARD
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WATS.
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EQUALIZATION The procedure of compensating for
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fluctuation in circuit amplitude, delay,
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or distortion.
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ERLANG A unit of traffic intensity. One Erlang
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is the intensity at which one traffic
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path would be countinuously occupied,
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e.g., one call per hour.
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ERLANG B TABLE A method for determining grade of
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service for a specified amount of
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traffic.
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ERROR RATE The probability of an error ocurring
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during the transmission of a message.
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EXCHANGE A telephone switching center.
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EXCHANGE AREA A geographical unit established within a
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telephone company's serving area for the
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adminastration of telephone service
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provided. One schedule of charges
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applies to the whole area. Usually
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served by one or more central offices
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and their associated outside plant.
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EXCAHNGE NETWORK FACILITIES FOR AT&T's pricing arrangement for local
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INTERSTATE ACCESS (ENFIA) loops offered to OCCs for connecting the
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OCC's network to the local telephone
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company's central office.
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EXPECTED MEASURED LOSS (EML) The calculated 1 kH loss of the trunk
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shown on the circuit or design layout
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record.
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EXTENDED AREA SERVICE (EAS) A telco tariff giving customers the
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option whereby the subscriber can pay a
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higher flat rate in order to obtain
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geographic coverage without additional
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per-call charges (non-toll charges).
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- F -
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FACILITY Synonym: Circuit.
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FACSMILE The transmission of pictures, maps or
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other documents via communications
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circuits using a device which scans the
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original document, transforms the image
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into coded signals and repoduces the
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original document at a distant point.
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FEDERAL COMMUNICATIONS COMMISON (FCC) The government agency established by the
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Communications Act of 1934 which
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regulates the interstate communications
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industry.
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FIBER OPTICS High speed transmisson using light to
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send images ( in telecommunications:
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voice or data ) through a flexible
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bundle of glass fibers.
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FOREIGN EXCHANGE LINES (FX) A special access hardwire circuit that
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provides service between a telephone at
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a customer's location and a distant
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central office.
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FOUR WIRE CIRCUIT A communications path which employs two
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separate electrical paths one receiving
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and one transmitting.
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FREQUENCY The number of complete cycles per unit
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of time.
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FREQUENCY RESPONSE The reaction of frequencies to the
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circuit components.
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FULL DUPLEX A circuit which allows transmission of a
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message in both directions at the same
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time.
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FULL PERIOD The condition of a switching system
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where each input a switching stage has
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access to every output from the stage.
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- G -
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GRADE OF SERVICE The probability of a call being blocked
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by busy trunks, expressed as a decimal
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fraction, and usually meaning the
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busy-hour probability.
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GROUP 12 circuits processed as a unit in a
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carrier system.
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- H -
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HALF DUPLEX A circuit for transmitting or receiving
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signals in one direction at a time.
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HANDSET That portion of the telephone containing
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the transmitter and receiver which is
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hand-held when the telephone is in use.
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HARDWARE Physical equipment or components of a
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computer system rather than a programmed
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method use.
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HARDWIRE To wire or cable directly between units
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of equipment.
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HARMONIC The full multiple of a base frequency.
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HARMONIC DISTORTION The ratio, expressed in decibels, of the
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power at the fundamental frequency, to
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the power of a harmonic of that
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fundamental.
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HEAD END HOP OFF (HEHO) A method of traffic engineering whereby
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calls are completed by using long
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distance facilities directly off the
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switch that serves that location.
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HERTZ (Hz) International standard unit of frequency.
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frequency. Replaces, and is identical
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to, the order unit "Cycles-per-second."
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HOMING Returning to the starting position, as
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in a starting switch.
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HOOKSWITCH The device on which the telephone
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receiver hangs or on which a telephone
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handset hangs or rests when not in use.
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The weight of the receiver or handset
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operates a switch which opens the
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telephone circuit, leaving only the bell
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connected to the line.
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HOT-CUT Virtually instantaneous replacement of
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one line with another.
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HYBRID An electronic circuit which performs the
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wire conversations necessary for the
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connection of a local loop with a
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long-haul facility.
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- I -
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INTERCEPT To stop a telephone call directed to an
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improper telephone number, and redirect
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that call to an operator or a recording.
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INTERCONNECT 1) The arrangement that permits the
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connection of customer's telecommunica-
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tions equipment to a communications
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common carrier network. 2) The industry
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name for manufacturers, excluding the
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Bell system, which provide CPE telephone
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equipment.
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INTER-EXCHANGE MILEAGE (IXC) The airline mileage between two cities.
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Synonym: Long Haul Mileage.
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INTEREXCHANGE PLANT The facilities between the subscriber
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switching center and another switching
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center.
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INTERFACE The junction or point of interconnection
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between two systems or equipment having
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different characteristics.
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INTERFERENCE Any unwanted noise or crosstalk on a
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communications circuit which acts to
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reduce the intelligibilty of the desired
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signal or speech.
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INTER-MACHINE TRUNK (IMT) A circuit which connects two automatic
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switching centers.
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INTER-OFFICE TRUNK (IOT) A direct trunk between local exchange
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offices.
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INTERNATIONAL RECORD CARRIER (IRC) Companies that handle the intra-U.S.
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portion of international record
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transmission.
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INTERSTATE Any connection made between two states.
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INTRASTATE Anyconnection made that remains within
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the boundaries of a single state.
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- J -
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JACK A connecting device having springs which
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make electrical contact with mating
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contacts of a plug.
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JITTER Short term instability of the amplitude
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and/or phase of a signal.
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Commonly called: PHASE JITTER.
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- K -
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KEYSET Multi-push button keys located on a
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telephone which may be punched in
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sequence for sending telephone number
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desired, precedence, or routing signals.
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KEY SYSTEM The equipment utilized to provide the
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features associated with key sets.
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- L -
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LEASED LINES Any circuit or combination of circuits
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designated to be at the exclusive
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disposal of a given subscriber.
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Synonym: Private Line.
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LEAST COST ROUTING (LCR) A method of automatically selecting the
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least costly facility for transmission
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of a call.
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Synonym: Most Economical Route Selection
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(MERS): Route Optimization.
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LEVEL An expression of the relative signal
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strength at a point in a communications
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circuit compared to a standard.
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LOADING A system for adding regularly spaced
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inductance units to a circuit to improve
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its transmission characteristics.
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LOCAL ACCESS AND TRANSPORT AREA Defines the local calling area as
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(LATA) established by the court ordered AT&T
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divestiture plan.
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LOCAL AREA NETWORK (LAN) Intraoffice communication system usually
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used to provide data transmission in
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addition to voice transmission.
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LOCAL LOOP The local connection between the end
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user and the Class 5 central office.
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LONG HAUL Circuits spanning considerable
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distances.
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LOOP BACK A method of performing transmission
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tests on a circuit not requiring the
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assistance of personnel at the distant
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end.
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LOOP SIGNALING Any of the three signaling methods which
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use the metallic loop formed by the
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trunk conductors and the terminating
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equipment bridges.
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- M -
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MAIN DISTRIBUTION FRAME (MDF) The point where outside plant cables
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terminate and from which they cross
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connect to terminal or central office
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line equipment.
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MAIN PBX A PBX directly connected to a switch via
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an access trunk group.
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MANUAL TIE LINE A tie line which requires the assistance
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of an attendant at both ends of the
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circuit in order to complete a call.
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MASTER GROUP (MG) 240 circuits processed as a unit in a
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carrier service.
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MESSAGE TELEPHONE SERVICE (MTS) AT&T's tariffed pricing name for long
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distance telephone calls.
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MESSAGE UNIT (MU) A local toll rate calling plan which is
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time and distance sensitive.
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METAL OXIDE SEMICONDUCTOR (MOS) A type of computer memory utilizing 1/4
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inch square slices of silicon. These
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silicon slices require constant electric
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current for the data to be retained.
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MICROWAVE (M/W) Radio transmission using very short
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lengths , corresponding to a frequency
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of 1,000 megahertz or greater.
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Synonym: Microwave Radio.
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MICROWAVE RADIO Synonym: Microwave.
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MODEM A device which modulates and demodulates
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signals on a carrier frequency and
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allows the interface of digital
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terminals with analog carrier systems.
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MODULATION Alterations in the characteristics of
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carrier waves. Usually impressed on the
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amplitude and/or the frequency.
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MONITORING DEVICE Records data on calls placed through a
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company's telephone system:number
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called, length of calls, calling
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location.
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MOST ECONOMICAL ROUTE SELECTION Synonym: Least Cost Routing
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(MERS)
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MULTIPLEXING The act of combining a number of
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individual message circuits for
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transmission over a common path. Two
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methods are used: (1) frequency
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division, and (2) time division.
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- N -
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NETWORK A collection of switches connected to
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one another by transmission facilities.
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NETWORK NUMBERING EXCHANGE (NNX) The three digit location code
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representing the central office. "N"
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may be any number between "2" and "9"
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and "X" may be any number.
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NETWORK TRUNKS Circuits connecting switching centers.
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NODE A terminal of any branch of a network.
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NON-BLOCKING A switching network having a sufficient
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number of paths such that a subscriber
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originating a call can always reach any
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other idle subscriber without
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encountering a busy.
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===============================================================================
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This concludes Part I Volume II of the MCI Telecommunications Glossary. Look
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for more G-philes on MCI by Knight Lightning coming soon to Metal Shop!
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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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