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TUCoPS :: Phreaking Technical System Info :: mcitg3.txt

MCI Telecom Glossary Pt.3

                                 _  _        _______
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                            The Dark Tower Phase II
                                 <314> 432-0756

                                Proudly Presents

                      The MCI Telecommunications Glossary

                           Part I Volume III (O - S)

                      Typed and edited by Knight Lightning


                                     - O -

OFFERED TRAFFIC                        The number of call attempts in any
                                       specified period of time.

OFF HOOK                               The condition which which results when a
                                       telephone handset is lifted from its
                                       mounting, allowing the hookswitch to

OFF NETWORK ACCESS LINE (ONAL)         A connection from a private switched
                                       service or transmission network accessing
                                       the public switched network.

OFF NETWORK CALLING                    Telephone calls through a private
                                       switching system and transmission network
                                       which extend to the public telephone

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 up its contacts.

ON NETWORK CALLING                     A term used to describe a call that
                                       originates and terminates on private

OPERATOR ASSISTED CALLS                Non-DDD calls requiring manual

ORIGINATING OFFICE                     The central office that serves the
                                       calling party.

OTHER COMMON CARRIER (OCC)             A company which provides long distance
                                       telephone services, other than AT&T.

OUT-OF-BAND                            Any frequency outside the band used for
                                       voice frequencies.

OUT-OF-BAND SIGNALING                  Use of a 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.

                                     - P -

PAD                                    A non-adjustable resistance network used
                                       to insert transmission loss into a

PHASE JITTER                           (See JITTER.)

POINT-TO-POINT                         A communications circuit between two
                                       terminations which does not connect with
                                       a public telephone system.

POLLING                                A progress by which a computer
                                       interrogates the "readiness to transmit"
                                       status outlying terminals.

PORT                                   (See COMPUTER PORT.)

POSTAL TELEPHONE AND TELEGRAPH (PTT)   Foreign government agencies responsible
                                       for regulating communications.

PRIMARY AREA                           A customer"s local telephone calling

PRIMARY ROUTING POINT                  The switch designated as the control
                                       point for a longhaul telephone call.

PRIVATE AUTOMATIC BRANCH EXCHANGE/     A switching system that provides internal
PRIVATE BRANCH EXCHANGE (PABX/PBX)     telephone communications between stations
                                       located on a customer's premises as well
                                       as between these stations and public or
                                       private telephone networks.

PRIVATE LINE                           A dedicated communications path for use
                                       between specific points.

PRIVATE LINE SERVICE                   Subscribers have dedicated, usually
                                       full-time communications facilities.
                                       Services can range from standard
                                       communications lines to highly
                                       sophisticated unique arrangements
                                       tailored to a customer need. Channels
                                       may be established between two points,
                                       (e.g., tie together several customer
                                       PABX's linking various locations.)
                                       Subscribers may elect to purchase
                                       transmission facilities  and create
                                       their own privately owned network.

PRIVATE USE NETWORK                    Two or more private line channels
                                       contracted for by a customer and
                                       restricted for use by the customer only.

PROGRAMMABLE READ ONLY MEMORY (PROM)   Memory which is electrically programmed
                                       by the equipment manufacturer into a
                                       computer and can only be changed with
                                       special equipment which erases the
                                       previous program. Unaffected by power

PROGRAMMED SPEED DIALING               Synonym:  Abbreviated Dialing.

PUBLIC SWITCHED NETWORK (PSN)          The nationwide network maintained by AT&T
                                       and the independent telephone companies
                                       which provide nationwide, unrestricted
                                       telephone service.

PUBLIC UTILITY COMMISION (PUC)/        The state commisions regulating
PUBLIC SERVICE COMMISION (PSC)         intrastate communications.

PULSE CODE MODULATION (PCM)            The conversation of an analog signal to a
                                       digital one through rapid sampling of the
                                       signal amplitude (minimum 7,000 samples
                                       per second).  Provides undistorted
                                       transmission, even in the presence of

PULSE-LINK REPEATER                    Connects one E&M signaling circuit
                                       directly to another.

PUSH BUTTON DIALING                    Synonym: Dual Tone Multi-Frequency.

                                     - Q -

QUEUE                                  A temporary delay in providing service
                                       caused by the inability of the system
                                       provided to handle the number of messages
                                       or calls attempted.

                                     - R -

RADIO COMMON CARRIER (RCC)             A communications common carrier that
                                       provides radio paging  and mobile
                                       telephone services to the public.

RANDAM ACCESS MEMORY (RAM)             That portion of a computer's memory which
                                       can be accessed non-sequentially and,
                                       therefore, is considered the "working

RATE CENTER                            A specified geographic location used by
                                       the telephone company to determine
                                       interchange mileage for rate.determina-
                                       tion purposes.

READ ONLY MEMORY (ROM)                 That portion of a computer's memory which
                                       is programmed electrically by the
                                       manufacturer, is unchangeable, and is
                                       unaffected by a power loss.

REDUNDANCY                             Duplicate equipment that is provided to
                                       minimize the effect of failures or
                                       equipment breakdowns.

REGENERATION                           The process of recieving distorted signal
                                       pulses and from them recreating new
                                       pulses at the correct repitition rate,
                                       pulse amplitude, and pulse width.

REGIONAL OPERATING COMPANY (ROC)       There are currently 7 ROC's which own 22

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                          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                         The telephone industry's term for a
                                       voice-frequency transformer.

RESELLER                               A business which buys services from one
                                       business at a bulk rate and sells
                                       portions of those services to multiple

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                          Synonym: Audible Ringing Tone.

RINGDOWN                               A circuit or a method of signaling where
                                       the incoming signal is actuated by
                                       alternating current over the circuit.

ROTARY DIAL                            A rotary mechanism having a ten-hole
                                       finger wheel which when wound up and
                                       released causes pulsing contacts to
                                       interrupt the line current and operate
                                       the central office selecting equipment in
                                       accordance with the digit dialed.

ROUTE GUIDE                            A map showing how a customer's calls are

ROUTE OPTIMIZATION                     Synonym: Least Cost Routing.

ROTARY HUNT                            An arrangement which allows calls placed
                                       to seek out an ideal circuit in a pre-
                                       arranged multi-circuit group and find the
                                       next open line to establish a through

                                     - S -

SATELLITE COMMUNICATIONS               A vehicle in geosynchronous orbit with
                                       the Earth which contains a source of
                                       energy, such as solar cells, and
                                       amplifies the signals it recieves
                                       before transmitting it back to Earth.

SECONDARY CARRIER                      Customer can override their primary
                                       carrier selection on a call by call basis
                                       and select other IC's to carry their long
                                       distance traffic in equal access areas.

SELECTIVE CALLING                      The ability of a transmitting station to
                                       specify by the use of assigned codes
                                       which of several stations is to receive a

SERVICE                                A group of circuits which terminate at
                                       the same location and provide the same

SERVICE AND EQUIPMENT RECORD           A list of equipment billed to customer by
                                       type, quantity, monthly charge, location,
                                       and billing dates.

SF SIGNALING (SINGLE-FREQUENCY)        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 circuits is
                                       in use.

SHORT HAUL                             Curcuits designated for use over
                                       distances of 10 - 200 miles.

SIGNALING                              A procedure for indicating to the
                                       receiving end of a communications circuit
                                       that data is to be transmitted

SIGNALING CONVERTER                    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, (b) E&M to SF.

SIGNALING, IN-BAND                     A type of signaling using an AC signal
                                       (usually a 2,600 Hz) within the normal
                                       voice band. This signal can be trans-
                                       mitted from and end to end of a long
                                       voice circuit without any intermediate
                                       signaling equipment. Since the signaling
                                       is audibile, the signaling equipment must
                                       be arranged for "tone on when idle"

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 gain exceeds
                                       the sum of the circuit losses.

SOFTWARE                               (1)  Any of the routines, programs, and
                                       instructions required to use computers.
                                       (2)  A written statement of the
                                       procedures to be used and the format of
                                       the data at every step.

SPECIAL GRADE NETWORK TRUNK            A trunk specially conditioned by
                                       providing amplitudeand delay
                                       equalization for the purpose of handling
                                       special services such as medium-speed
                                       data (600 to 2400 BPS).

SPECIALIZED COMMON CARRIER             A new type of common carrier specializing
                                       in providing transmission facilities.
                                       (e.g., Microwave Communication Inc.(MCI),
                                       Southern Pacific Communication Co.(SPC),
                                       and the satelite communication companies
                                       like Satellite Business System (SBS).)

SPEED NUMBER                           A one, three, or four digit number that
                                       replaces a seven or ten digit telephone
                                       number. These numbers are programmed

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