Telephone Terminolgy Written by Elric of Imrryr Lunatic Labs UnLimited A & A BUREAU: Abuse & Annoyance Bureau. The personal in this line of work spend their time helping customers get rid of nuts, obscene callers, harassing collectors, etc. ACCESS: The existence of paths within a network from an input terminal to a set of output terminals in the absence of traffic is indicated by the term, ACCESS. Full access permits connecting to all output terminals by unique paths; multiple access indicates that all output terminals can be reached in more than one way; partial access refers to the ability to reach only a fraction of the output terminals ACCESSIBILITY--(availability): The number of trunks of the required route in a switching network which can be reached from an inlet. ADAPTOR: A device designed to switch a number of voice-frequency telephone channels coming from a non-time-division switching system to a time-division multiplex highway. ALIASING: The occurrence of spurious frequencies in the output of a PCM system that were not present in the input, due to foldover of higher frequencies. ALTERNATE ROUTING: A procedure by which several routes involve different switching stages or networks. Usually the route having the fewest switching stages is tested first. ANALOG TRANSMISSION: The transmission of continuously variable signals rather than descretely variable signals. Prior to the use of digital encoding and PCM, it was the only way of transmitting voice signals over telephone channels ASYNCHRONOUS SYSTEM: A system in which the transmission of each information character is individually synchronized usually by the use of start and stop elements. AUTOVON: AUTOmatic VOice Network AVERAGE HOLDING TIME: The average duration of a call expressed in seconds or minutes. BIT: The smallest binary unit of information. A contraction of the word binary digit. BIT RATE: The rate or speed at which bits are transmitted. Bits per second is a common measure. BLOCKING (CONGESTION): A condition where the immediate establishment of a new connection is impossible due to the lack of available paths, or the inability to interconnect two idle network terminals because some of the applicable links between them are used for other connections. BORSCHT: An acronym for the functions that must be performed in the CO when digital voice transmission occurs: Battery, Overvoltage, Ringing, Supervision, Coding, Hybrid, and Test Business Office Supervisor (BOS):The boss of the service representatives BROADBAND EXCHANGE (BEX): Public switched communication system featuring full duplex (FDX) connections of various bandwidths. A Western Union facility. BUSINESS SERVICE INSTRUCTOR (BSI): A traffic employee who will come out and teach you how to use your phone system. BUSY HOUR: An uninterrupted period of 60 minutes in which the total traffic of a sample is maximum. BYTE: A unit of information in electronic computer terminology consisting of 8 bits, referred to as extended binary coded decimal information of an EBCDIC code. CALL CONGESTION RATIO: The ratio of the time during which congestion exists to the total time considered. It is an estimate of the probability that an external observer will find a system in a congested condition. CALLING RATE: Average calls per subscriber per hour. CALL STORE: The memory section of a stored program control switching system in which temporary information used in the processing of calls through the exchange is contained. It is also referred to as the Process Store. CELL: In cellular mobile telephony, the geographic area served by one transmitter. Subscribers may move from cell to cell. CENTRAL OFFICE: Exchanges where subscriber lines and PBX lines terminate. There they are switched to provided the "desired" connection with other subscribers. Such an exchange is called an end office and is designated as a Class 5 office in the U.S. CENTRAL OFFICE SWITCH: (CO SW) This term is used to describe a connection point which gives access to the DDD network. CENTRAL PROCESSOR: The main computer element of a stored program control switching system, which under the direction of the stored program establishes switching network connections and also monitors and analyzes the system to insure proper operation. Routine process testing, maintenance and administrative funtions are also carried out. CENTREX: A PBX system in which the switching equipment is located centrally and away from the location being served. Direct inward dialing (DID) and direct outward dialing (DOD) as well as automatic number identification (ANI) are provided by such a system. CHANNEL: An electronic commications path, usually of 4,000 Hz (voice) bandwidth. COMMON BATTERY: A system of supplying direct current for the telephone set from the central office. CONCENTRATORS: Equipment used to connect a large number of path, for example: ANSWERING SERVICE CONCENTRATORS: Equipment provided in local central offices which, together with identifying equipment at the answering service location makes it possible to answer a large number of customer lines on a few pairs CROSSBAR SWITCH:An electromechanical switching machine utilizing a relay mechanism with horizontal and vertical input lines (usually 10 by 20), using a contact matrix to connect any vertical to any horizontal. CROSSPOINT: The element that actually performs the switching functions in a telephone system. May be mechanical using metal contacts, or solid-state using integrated circuits. CUSTOMER:The person, firm, or corporation which orders service and is reponsible for the payment of charges and compliance with Telephone Company regulations. CUSTOMER-PROVIDED EQUIPMENT (CPE): This includes any equipment provided by the customer and connecting to the Telephone Company facilities. This equipment may be customer-provided and maintained (CPM) or customer-provided and telephone maintained (CPT). CUT-OFF FREQUENCY: The frequency above or below which signals are blocked by a circuit or network. DATA SET: Telephone company term for a modem. DIAL PULSING: A system of dc pulsing in which the digits are transmitted by the interruption of the dc circuit a number of times, one to ten interruptions corresponding DIAL TONE:A tone used in dial telephone systems to indicate that the equipment is ready for the dialing operation. This tone is 600Hz modulated by 120Hz when supplied by a tone alternator of 133Hz when supplied by an interrupter. The modulating frequency gives this tone its low-pitched sound. Interrupted low tone is used for line busy reorder, and no ciruit tone signals reached by the customer DIRECT DISTANCE DIAL (DDD) NETWORK: All Bell and Independent Telephone Company equipment and facilities used to permit customers to dial their own long distance (toll) calls. DTMF: Dual-Tone-Multi-Frequency; Use of two simultaneous voice-bandsb tones for dialing. ESS: Electronic Switching System; A telephone switching machine using electronics, often combined with electromechanical crosspoints, and usually with a stored-program computer as the control element. EXCHANGE AREA: The territory within which telephone service is provided without extra charge. Also calling Local Calling Area or just Exchange. JUMPER: Two wires (a pair) twisted together and used on the frame to connect equipment and cables which provide customer service. LINE: Any type of circuit terminated in a telephone or equivalent at one end and a switching machine at the other end. LINESIDE: Refers to the portion of the central office that connects to the local loop. LOADED CABLE: Cable designed with LOAD POTS at designated intervals to balence tranmission characteristics of the voice frequencies, 300 to 3200 Hz. LOAD POTS (LOAD COILS): Load Poits are indutance coils arranged at designed intervals to balence transmission characteristics of the voice frequen- cies 300 to 3200Hz. LOCAL CHANNEL: The local Channel is the cable, or the outside wire, used to connect the serving CO to the customer location LOCAL LOOP:The voice-band channel connecting the subscriber to the central office LOSS: The decrease in energy, expressed in dB, between two points in a circuit. MESSAGE TELEPHONE SERVICE (MTS): The official name for long distance or toll service. NON-LOADED CABLE (NL): Cable without LOAD POTS to balence the transmission characteri OFF-HOOK: The condition that indicates the active state of a customer telephone circuit. The opposite condition is On-Hook. On-Hook: The condition that indicates the idle state (loop open) of a station line on other circuit. PABX or PBX: A private (automatic) branch telephone exchange system providing telephone switching in an office or building. PADS: A resistance network of value needed to introduce a specific transmission loss. Protector: A device used to prevent damage to lines or equipment by dangerously high voltages or currents. The device may be a sparkgap, varistor, thermistor, etc. The device usually has a very high resistance to ground until the presence of an abnormal voltage or current causes the resistance to decrease. The device will then conduct and eliminate thhe dangerous condition. PULSE CODE MODULATION: (PCM) A communication system technique of coding signals with binary codes to carry informations. RADIO COMMON CARRIER: (RCC) A company that provides mobile telephone service, but is not a telephone company. Repeat Coil: Two or more windings, each magnetically coupled to all other windings. Used for impedance matching facilities and equipment, simplexing and isolation. In signaling equipment repeat coils are used to pass VF(ac) while blocking dc. Repeater: An electronic device used on long circuits to amplify voice signals and/or repeat supervision, (D.C.) signals. (One of those often seen on telepone poles. RING: The alerting signal to the subscriber or terminal equipment; the name for one conductor of a wire pair, designated by R. Station (STA): Denotes transmitting and/or receiving equipment at any location on a customer's premises. SUBSCRIBER LINE INTERFACE CIRCUIT: (SLIC) In digital transmission of voice , the circuit which performs some or all of the interface functions at the central office. See BORSCHT. TIE PAIRS: TIE PAIRS are terminations on a frame block which will provide connections between frames. These connections are a wire path from one piece of equipment to another. Their only purpose is to tie equipment that is not located on the same frame or floor together. TIE PAIRS function as an extension cord. TOLL CALL: Any call for a destination outside of the local service area of the calling station. TRUNK CABLE: Trunk Cable, sometimes called Exchange Cable, is used to connect one central office to another. Trunk Cable is inventoried in the Facility System therefore the assignments are on the Circuit Layout Record (CLR).