Frequently used telephone terms, acronyms and abbreviations with a brief
definition of each:
ABD - Average Business Day; message figure based on telephone messages handled
Monday through Friday.
ACCESS CODE - Number prefix a subscriber dials to reach the nationwide long
AMA - Automatic Message Accounting; automatically records the data needed for
billing customer-dialed long distance calls.
AMPLIFIER - Device for boosting the energy of communications signals.
ANC - All Number Calling; system of telephone numbering that uses seven digits
within a Numbering Plan Area.
ANI - Automatic Number Identification; equipment that automatically records the
calling number. This is part of automatic message accounting.
AREA CODE - Three-digit code used in dialing long distance calls from one
Numbering Plan Area to another.
BELLCOMM, INC. - Bell System company formed in 1962 to assist National Aeronautics
and Space Administration.
BME - Basic Medical Expense Plan; hospitalization and
medical insurance plan for employees.
BSP - Bell System Practices; detailed procedures written by Bell System companies
to cover nearly every phase of the business.
BY - Subscriber's line is busy.
BY-PASS ROUTES - Lines, cables, or systems that go around key cities.
CALCULAGRAPH - Clock used by operators to record duration of calls.
CATV - Community Antenna Television;
service that carries TV signals from antenna tower straight to
subscriber's home; subscribers buy the service directly from the operator of the
CARD DIALER - Automatic pushbutton dialer combined with regular telephone; phone
numbers coded on plastic cards are inserted in dialer slot for fast, accurate
CARRIER - Equipment that electronically stacks one voice on top of another at the
beginning end and separates them at the receiving end.
CCITT - International Telegraph and Telephone Consultative Committee; an
organization that sets standards and promotes worldwide cooperation in
CENTRAL OFFICE - Switching unit in telephone system providing service to general
CENTREX - Type of private branch exchange (PBX) that enables incoming calls to be
dialed direct to any extension, and lets extension users dial their own calls
without switchboard assistance.
CHANNEL - Electrical path furnished by the telephone company for communications
purposes between two or more points.
DATA LANGUAGE - Language of computers and other business machines expressed as
perforations on tape, punched holes on cards, or electronic Impressions on
DATA-PHONE SERVICE - With Data-Phone sets, customers can transmit wide range of
data from one business machine to another over the telephone network.
DATASPEED* TAPE-TO-TAPE TRANSMISSION - Transmits over the telephone network at
more than 1,000 words a minute.
DDD - Direct Distance Dialing; easy, fast telephone service which permits
customers to dial their own long distance calls.
DID - Direct Inward Dialing; enables outside calls to be dialed direct to
extensions without going through a switchboard
DOD - Direct Outward Dialing; the reverse of DID: an extension user dials out
without switchboard assistance.
DROP - Wire that leads from customer's premises to cable connected with central
ECO - Electronic Central Office; telephone office that uses electronic switching.
EDP - Electronic Data Processing; computer processing of a series of operations.
EME - Extraordinary Medical Expense Plan; company-sponsored plan that applies when
coverage in Basic Medical Expense Plan is exceeded.
ESS - Electronic Switching System; using computer-type equipment and operating at
lightning speed, this system makes possible many additional services for
ETV - Educational Television; service offering for transmission of televised
instruction; term also used by broadcasters to describe instructional and
EXCHANGE - Unit of territory for telephone rate purposes; includes city, village
or other community and is served by one or more central offices.
EXECUTIVE INSTRUCTIONS - Set of instructions by vine president in charge of Long
Lines which assigns responsibilities and delegates authorities to Individuals by
FACILITIES - Non-specific catchall word for telephone equipment,
installations, systems or complex of property and equipment.
FACSIMILE TRANSMISSION - Transmission of handwritten messages or sketches by means
of private line or, when associated with Data-Phone® set, over the
regular telephone network
HARDENED - Term for blast-resistant construction.
LASER - Device that produces a coherent light beam so intense that it has
potential as a communications carrier.
LOCAL CALL - Any call within the local calling area.
LOCAL CALLING AREA - The area, consisting of one or more exchanges within which
calls may be made without a toll charge.
LONG DISTANCE CALL - Any call beyond the local calling area.
MARK SENSE - To record billing information while handling calls, operators mark
preprinted cards with graphite pencils; data processing machines respond to the
cards as though they were punched.
MASER - Precision amplifier developed for satellite communications which will
amplify very weak signals.
MEASURED RATE SERVICE - Monthly rate for local telephone service which provides
for a specified number of message units; any over that amount are charged for.
MESSAGE - Completed communication; telephone call becomes message when
conversation takes place between the calling and called persons.
MESSAGE UNIT - Unit of charge for local calls within local service areas where
multi-unit rate treatment is applicable.
MICROWAVE - Line-of-sight radio transmission using super-high frequencies.
NC - No circuit: available.
NON-LIST - Telephone numbers not listed in the directories but included
records of directory assistance operators.
NON-PUBLISHED- Telephone numbers neither listed in directories nor available in
records of directory assistance.
PBX -. Private Branch Exchange; switching system of business or other
organization which serves its telephones over a common group of lines from the
PEG COUNT - A count of the number of times a circuit or piece of apparatus is used
in a given period.
PRIVATE LINE - Point-to-point communications arrangement apart from the regular
exchange or toll system; also used to refer to an individual line as against a
RELAY - An electromagnetic device which operates other devices such as switches
and spring contacts.
SEEING-AID SYSTEM - Sensing device which indicates switchboard line and permits
blind persons to operate switchboards.
SERVICE CODES - Codes for reaching telephone company services such as repair,
directory assistance and business office.
SOLAR CELL - Device which derives electrical energy from light.
STATION - Telephone or teletypewriter on customer premises through which service
is furnished. A main station is just that; an extension, an additional set.
SWITCHED NETWORK - Nationwide complex of diversified channels and reliable
switching equipment that automatically routes communications to their
TASI - Equipment used with underseas cables to double conversation capacity; takes
advantage of times when people are listening or pausing the voice channels they
leave temporarily unused are automatically assigned to other talkers.
TELSTAR - Bell System's experiments with Telstar I and II in early '60s proved
feasibility of transmitting all kinds of communications via satellite and paved
way to commercial service.
TICKET - Record made by an operator of information required for billing a long
TOUCH-TONE® TELEPHONE - Phone with electronic pushbuttons that allow
calls to be made more quickly and conveniently than with rotary dials.
TSP - Traffic Service Position; console with pushbutton equipment that reflects
the operator's role as service specialist.
TTY - Teletypewriter; equipment used to transmit and receive a typed record at
relatively low speeds, generally from 60 to 100 words per minute.
TTYS - Teletypesetter; special type of teletypewriter equipment linked to linotype
machine which automatically sets a teletypewriter message in metal type.
WATS - Wide Area Telephone Service; customer can make all calls he wants at flat
monthly rate; service is available across continental U.S., or by region, on
full or measured time basis.
*Service mark of the Bell System
Some books and pamphlets for additional information on the telephone
Alexander Graham Bell
AT&T Annual Report
AT&T Your Business
At Your Service (how the Bell System maintains its nationwide network)
Bell System Overseas Telephone Serwce
Business Purposeand Performance, by Frederick R. Kappel
Early Corporate Development of the Telephone
Events in Telephone History
Laser :the New Light
Long Lines and You( for new employees)
Project Telstar (Bell System experiments in space communications)
Signals in Space (the Bell System's role in space)
The Birth and Babyhood of the Telephone, by Thomas Watson
The Telephone at Your Command( nontechnical explanation)
The Telephone in America (the Bell System, its function and parts)
The Transistor Age
The24 Partners (Division of Revenues)
The World's Telephones (statistics)
Vitality in a Business Enterprise, by Frederick R. Kappel