470 lines
16 KiB
Plaintext
470 lines
16 KiB
Plaintext
===============================================================================
|
||
_ _ _______
|
||
| \/ | / _____/
|
||
|_||_|etal/ /hop
|
||
_________/ /
|
||
/__________/
|
||
|
||
(314)432-0756
|
||
|
||
Proudly Presents
|
||
|
||
The MCI Telecommunications Glossary
|
||
|
||
Part I Volume II (E - N)
|
||
|
||
Typed and Edited by Knight Lightning
|
||
|
||
===============================================================================
|
||
|
||
|
||
- E -
|
||
|
||
|
||
ECHO A signal that has been reflected or
|
||
otherwise returned with sufficient
|
||
magnitude and delay to be percieved by
|
||
the speaker.
|
||
|
||
ECHO RETURN LOSS (ERL) The loss which must be in the echo path
|
||
to reduce echo to a tolerable amount.
|
||
|
||
ECHO SUPRESSOR A device which detects speech signals
|
||
transmitted in either direction on a
|
||
four-way circuit, and introduces loss
|
||
in the direction of transmission.
|
||
|
||
EIGHT HUNDRED SERVICE (800) A commonly used reference for inward
|
||
WATS service (See WATS, Inward).
|
||
|
||
EITHER END HOP OFF (EEHO) Uses either Head Hop Off or Tail End Hop
|
||
Off.
|
||
|
||
ELECTRONIC DATA PROCESSING The use of electronic memories to store,
|
||
up-date, read, and use information.
|
||
|
||
ELECTRONIC KEY TELEPHONE SETS (EKTS) A generic term indicating key telephones
|
||
with special buttons which are
|
||
electronically programmed to access
|
||
various PBX features.
|
||
|
||
ELECTRONIC SWITCHING SYSTEM (ESS) A Bell System term for electronic
|
||
exchange switching equipment.
|
||
|
||
ELECTRONICALLY PROGRAMMABLE READ Memory which is initially programmed by
|
||
ONLY MEMORY (EPROM) the manufacturer. Changes can be made
|
||
to conform to the customer requirements
|
||
at their premises.
|
||
|
||
ELECTRONIC TANDEM NETWORK (ETN) 1. A private network automatically and
|
||
electronically connecting the calling
|
||
office to the called office through
|
||
Tandem-Tie-Trunks. The network switches
|
||
also function as PBX's. 2. An AT&T
|
||
product name. 3. Used as a generic term
|
||
a PBX base network.
|
||
|
||
END OFFICE CONVERSATION When an end office offers equal access.
|
||
|
||
ENHANCED PRIVATE SWITCHED A private network utilizing Bell
|
||
COMMUNICATIONS SERVICE (EPSCS) provided equipment located in the
|
||
central office and dedicated to a
|
||
specific customer.
|
||
|
||
E&M LEADS A pair of leads which carry signals
|
||
between trunk equipment and separate
|
||
signaling equipment unit. The M lead
|
||
transmits battery or ground signals to
|
||
the signaling equipment, and the E lead
|
||
receives open or ground signals from the
|
||
signaling equipment.
|
||
|
||
E&M SIGNALING An arrangement whereby signaling between
|
||
a trunk circuit and an associated
|
||
signaling unit is effected over two
|
||
leads providing full-time, 2-way,
|
||
2-level supervision.
|
||
|
||
ENTERPRISE NUMBER A unique telephone exchange number that
|
||
permits the called party to be
|
||
automatically billed for the incoming
|
||
calls.
|
||
Synonym: "Toll Free Number;" INWARD
|
||
WATS.
|
||
|
||
EQUALIZATION The procedure of compensating for
|
||
fluctuation in circuit amplitude, delay,
|
||
or distortion.
|
||
|
||
ERLANG A unit of traffic intensity. One Erlang
|
||
is the intensity at which one traffic
|
||
path would be countinuously occupied,
|
||
e.g., one call per hour.
|
||
|
||
ERLANG B TABLE A method for determining grade of
|
||
service for a specified amount of
|
||
traffic.
|
||
|
||
ERROR RATE The probability of an error ocurring
|
||
during the transmission of a message.
|
||
|
||
EXCHANGE A telephone switching center.
|
||
|
||
EXCHANGE AREA A geographical unit established within a
|
||
telephone company's serving area for the
|
||
adminastration of telephone service
|
||
provided. One schedule of charges
|
||
applies to the whole area. Usually
|
||
served by one or more central offices
|
||
and their associated outside plant.
|
||
|
||
EXCAHNGE NETWORK FACILITIES FOR AT&T's pricing arrangement for local
|
||
INTERSTATE ACCESS (ENFIA) loops offered to OCCs for connecting the
|
||
OCC's network to the local telephone
|
||
company's central office.
|
||
|
||
EXPECTED MEASURED LOSS (EML) The calculated 1 kH loss of the trunk
|
||
shown on the circuit or design layout
|
||
record.
|
||
|
||
EXTENDED AREA SERVICE (EAS) A telco tariff giving customers the
|
||
option whereby the subscriber can pay a
|
||
higher flat rate in order to obtain
|
||
geographic coverage without additional
|
||
per-call charges (non-toll charges).
|
||
|
||
|
||
|
||
|
||
- F -
|
||
|
||
|
||
|
||
|
||
FACILITY Synonym: Circuit.
|
||
|
||
FACSMILE 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 repoduces the
|
||
original document at a distant point.
|
||
|
||
FEDERAL COMMUNICATIONS COMMISON (FCC) The government agency established by the
|
||
Communications Act of 1934 which
|
||
regulates the interstate communications
|
||
industry.
|
||
|
||
FIBER OPTICS High speed transmisson using light to
|
||
send images ( in telecommunications:
|
||
voice or data ) through a flexible
|
||
bundle of glass fibers.
|
||
|
||
FOREIGN EXCHANGE LINES (FX) A special access hardwire circuit that
|
||
provides service between a telephone at
|
||
a customer's location and a distant
|
||
central office.
|
||
|
||
FOUR WIRE CIRCUIT A communications path which employs two
|
||
separate electrical paths one receiving
|
||
and one transmitting.
|
||
|
||
FREQUENCY The number of complete cycles per unit
|
||
of time.
|
||
|
||
FREQUENCY RESPONSE The reaction of frequencies to the
|
||
circuit components.
|
||
|
||
FULL DUPLEX A circuit which allows transmission of a
|
||
message in both directions at the same
|
||
time.
|
||
|
||
FULL PERIOD The condition of a switching system
|
||
where each input a switching stage has
|
||
access to every output from the stage.
|
||
|
||
|
||
- G -
|
||
|
||
|
||
|
||
GRADE OF SERVICE 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.
|
||
|
||
|
||
|
||
- H -
|
||
|
||
|
||
|
||
HALF DUPLEX A circuit for transmitting or receiving
|
||
signals in one direction at a time.
|
||
|
||
HANDSET That portion of the telephone containing
|
||
the transmitter and receiver which is
|
||
hand-held when the telephone is in use.
|
||
|
||
HARDWARE Physical equipment or components of a
|
||
computer system rather than a programmed
|
||
method use.
|
||
|
||
HARDWIRE To wire or cable directly between units
|
||
of equipment.
|
||
|
||
HARMONIC The full multiple of a base frequency.
|
||
|
||
HARMONIC DISTORTION 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.
|
||
frequency. Replaces, and is identical
|
||
to, the order unit "Cycles-per-second."
|
||
|
||
HOMING Returning to the starting position, as
|
||
in a starting 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 conversations necessary for the
|
||
connection of a local loop with a
|
||
long-haul facility.
|
||
|
||
|
||
|
||
- I -
|
||
|
||
|
||
INTERCEPT To stop a telephone call directed to an
|
||
improper telephone number, and redirect
|
||
that call to an operator or a recording.
|
||
|
||
INTERCONNECT 1) The arrangement that permits the
|
||
connection of customer's telecommunica-
|
||
tions equipment to a communications
|
||
common carrier network. 2) The industry
|
||
name for manufacturers, excluding the
|
||
Bell system, which provide CPE telephone
|
||
equipment.
|
||
|
||
INTER-EXCHANGE MILEAGE (IXC) The airline mileage between two cities.
|
||
Synonym: Long Haul Mileage.
|
||
|
||
INTEREXCHANGE PLANT 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 intelligibilty 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) Companies that handle the intra-U.S.
|
||
portion of international record
|
||
transmission.
|
||
|
||
INTERSTATE Any connection made between two states.
|
||
|
||
INTRASTATE Anyconnection made that remains within
|
||
the boundaries of a single state.
|
||
|
||
|
||
- J -
|
||
|
||
|
||
JACK A connecting device having springs which
|
||
make electrical contact with mating
|
||
contacts of a plug.
|
||
|
||
JITTER Short term instability of the amplitude
|
||
and/or phase of a signal.
|
||
Commonly called: PHASE JITTER.
|
||
|
||
|
||
- K -
|
||
|
||
|
||
|
||
KEYSET Multi-push button keys located on a
|
||
telephone which may be punched in
|
||
sequence for sending telephone number
|
||
desired, precedence, or routing signals.
|
||
|
||
KEY SYSTEM The equipment utilized to provide the
|
||
features associated with key sets.
|
||
|
||
|
||
- L -
|
||
|
||
LEASED LINES Any circuit or combination of circuits
|
||
designated to be at the exclusive
|
||
disposal of a given subscriber.
|
||
Synonym: Private 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): Route Optimization.
|
||
|
||
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 Defines the local calling area as
|
||
(LATA) established by the court ordered AT&T
|
||
divestiture plan.
|
||
|
||
LOCAL AREA NETWORK (LAN) Intraoffice communication system usually
|
||
used to provide data transmission in
|
||
addition to voice transmission.
|
||
|
||
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.
|
||
|
||
|
||
|
||
|
||
- M -
|
||
|
||
|
||
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 A PBX directly connected to a switch via
|
||
an access trunk group.
|
||
|
||
MANUAL 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 service.
|
||
|
||
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.
|
||
|
||
METAL OXIDE SEMICONDUCTOR (MOS) A type of computer memory utilizing 1/4
|
||
inch square slices of silicon. These
|
||
silicon slices require constant electric
|
||
current for the data to be retained.
|
||
|
||
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.
|
||
|
||
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 Synonym: Least Cost Routing
|
||
(MERS)
|
||
|
||
MULTIPLEXING 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.
|
||
|
||
|
||
|
||
|
||
- N -
|
||
|
||
|
||
NETWORK A collection of switches connected to
|
||
one another by transmission facilities.
|
||
|
||
NETWORK NUMBERING EXCHANGE (NNX) 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.
|
||
|
||
NODE A terminal of any branch 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.
|
||
|
||
===============================================================================
|
||
This concludes Part I Volume II of the MCI Telecommunications Glossary. Look
|
||
for more G-philes on MCI by Knight Lightning coming soon to Metal Shop!
|
||
|
||
This has been a 2600 Club production
|
||
|
||
Thanx to Taran King
|
||
|
||
Call The Works BBS - 1600+ Textfiles! - [914]/238-8195 - 300/1200 - Always Open
|
||
|