Telecommunications Acronyms and Glossary

2780: AT BATCH STANDARD USED TO COMMUNICATE WITH IBM MAINFRAMES OR COMPATIBLE SYSTEMS.
3270: IBM'S INTERACTIVE COMMUNICATIONS TERMINAL STANDARD USED TO COMMUNICATE WITH AN IBM MAINFRAME OR COMPATIBLE SYSTEM.
3780: A BATCH PROTOCOL USED TO COMMUNICATE WITH AN IBM MAINFRAME OR COMPATIBLE SYSTEM.
ABSORPTION: CONVERSION OF TRANSMITTED ENERGY, SUCH AS AN ELECTRONIC SIGNAL, INTO HEAT OR OTHER FORMS OF ENERGY.
ACC: AUTOMATIC CALLBACK CALLING. FEATURE THAT ALLOWS THE STATION USER, WHEN ENCOUNTERING AN INTERNAL STATION BUSY SIGNAL, TO DIAL A 1- OR 2-DIGIT CODE AND HANG UP. WHEN BOTH PARTIES ARE FREE, THE SYSTEM AUTOMATICALLY RINGS AND CONNECTS THE PARTIES. WHILE ACTIVATED, THIS FEATURE DOES NOT PREVENT THE CALLING STATION FROM EITHER INITIATING OR RECEIVING CALLS.
ACCEPTANCE TEST: OPERATING AND TESTING OF A NEW SYSTEM TO ENSURE THAT THE SYSTEM IS OPERATING SATISFACTORILY BEFORE BEING ACCEPTED BY THE PURCHASER.
ACCESS: TO OBTAIN DATA FROM MEMORY, A PERIPHERAL, OR ANOTHER SYSTEM.
ACCESS ARM: THE MECHANICAL DEVICE IN A DISK STORAGE UNIT THAT HOLDS ONE OR MORE READ/WRITE HEADS.
ACCESS CHARGE: COST ASSESSED TO COMMUNICATIONS USERS FOR ACCESS TO THE INTEREXCHANGE, INTERSTATE MESSAGE TOLL TELEPHONE NETWORK TO ORIGINATE AND RECEIVE INTERSTATE TOLL CALLS, AS WELL AS ACCESS TO THE CUSTOMER'S LOCAL ACCESS AND TRANSPORT AREA (LATA).
ACCESS CODE: THE DIGIT, OR DIGITS, THAT A USER MUST DIAL TO BE CONNECTED TO AN OUTGOING TRUNK FACILITY.
ACCESS CONTROL: HARDWARE, SOFTWARE, AND ADMINISTRATIVE TASKS THAT MONITOR SYSTEM OPERATION, PERFORM USER IDENTIFICATION, AND RECORD SYSTEM ACCESSES AND CHANGES.
ACCESS LINE: CONNECTION FROM THE CUSTOMER TO THE LOCAL TELEPHONE COMPANY FOR ACCESS TO THE TELEPHONE NETWORK; ALSO REPRESENTS THE CONNECTION BETWEEN THE SERVING TOLL CENTER AND THE SERVING OFFICE OF THE INTEREXCHANGE CARRIER USED FOR ACCESS TO PUBLIC SWITCHED NETWORK SERVICES. ALSO KNOWN AS LOCAL LOOP.
ACCESS METHOD: THE TECHNIQUE AND/OR THE PROGRAM CODE IN A COMPUTER OPERATING SYSTEM THAT PROVIDES INPUT/OUTPUT SERVICES. THE ACCESS METHOD TYPICALLY CARRIES WITH IT AN IMPLIED DATA AND/OR FILE STRUCTURE WITH LOGICALLY SIMILAR DEVICES SHARING ACCESS METHODS.
ACCESS TIME: THE INTERVAL BETWEEN A REQUEST TO READ OR STORE DATA AND THE COMPLETION OF THAT TASK.
ACD: AUTOMATIC CALL DISTRIBUTOR. SYSTEM DESIGNED TO DISTRIBUTE A LARGE VOLUME OF INCOMING CALLS UNIFORMLY TO A NUMBER OF OPERATORS OR AGENTS. E.G., FOR AIRLINE RESERVATIONS.
ACF: ADVANCED COMMUNICATIONS FUNCTION. A SERIES OF SOFTWARE PRODUCTS BY IBM THAT SUPPORTS SOPHISTICATED COMPUTER NETWORKING FUNCTIONS FOR IBM SYSTEMS AND TERMINALS.
ACK: "ACKNOWLEDGE" CHARACTER. A TRANSMISSION CONTROL CHARACTER TRANSMITTED BY A STATION AS AN AFFIRMATIVE RESPONSE TO THE STATION WITH WHICH A CONNECTION HAS BE SET UP. AN ACKNOWLEDGE CHARACTER MAY ALSO BE USED A AN ACCURACY CONTROL CHARACTER.
ACOUSTIC COUPLER: A DEVICE THAT CONVERTS ELECTRICAL SIGNALS INTO AUDIO SIGNALS ENABLING DATA TO BE TRANSMITTED OVER THE PUBLIC TELEPHONE NETWORK VIA A CONVENTIONAL TELEPHONE.
ACU: AUTOMATIC CALLING UNIT. A DIALING DEVICE SUPPLIED BY THE COMMUNICATIONS COMMON CARRIER.
ADAPTER: A CONNECTIVE DEVICE DESIGNED TO LINK DIFFERENT PARTS OF ONE OR MORE SYSTEMS AND/OR SUBSYSTEMS.
ADAPTIVE EQUALIZATION: EQUALIZATION THAT IS ADJUSTED WHILE SIGNALS ARE BEING TRANSMITTED IN ORDER TO ADAPT TO CHANGING LINE CHARACTERISTICS.
ADAPTIVE ROUTING: ROUTING THAT AUTOMATICALLY ADJUSTS TO NETWORK CHANGES SUCH AS CHANGES OF TRAFFIC PATTERN OR FAILURES.
ADC: ANALOG-TO-DIGITAL CONVERSION. A METHOD OF SAMPLING AND COSTING AN ANALOG SIGNAL TO CREATE A DIGITAL SIGNAL.
ADCCP: ADVANCED DATA COMMUNICATIONS CONTROL PROCEDURES. THIS IS THE ANSI VERSION OF A BIT-ORIENTED DLC, BSR 3.66.
ADPCM: ADAPTIVE DIFFERENTIAL PULSE CODE MODULATION. ENCODING TECHNIQUE (CCITT) THAT ALLOWS ANALOG VOICE SIGNALS TO BE CARRIED ON A 32K BPS DIGITAL CHANNEL. SAMPLING IS DONE AT 8KHZ WITH 3 OR 4 BITS USED TO DESCRIBE THE DIFFERENCE BETWEEN ADJACENT SAMPLES.
ADVANCED MOBILE PHONE SERVICE: AT&T DEVELOPED ANALOG CELLULAR RADIO STANDARD, ADOPTED IN THE USA AND IN MAY OTHER PARTS OF THE WORLD.
AGCOMNET: U.S. DEPARTMENT OF AGRICULTURE'S VOICE AND DATA COMMUNICATIONS NETWORK
ALGORITHM: A PRESCRIBED SET OF WELL-DEFINED RULES FOR THE SOLUTION OF A PROBLEM IN FINITE NUMBER OF STEPS, EG., A FULL STATEMENT OF AN ARITHMETIC PROCEDURE FOR EVALUATING SINE X TO A STATED PRECISION.
ALU: ARITHMETIC LOGIC UNIT. PART OF A COMPUTER THAT PERFORMS THE ACTUAL COMPUTATIONS.
AM: AMPLITUDE MODULATION. A METHOD OF TRANSMISSION WHEREBY THE AMPLITUDE OF THE CARRIER FREQUENCY IS MODIFIED IN ACCORDANCE WITH THE BIT VALUE OF THE INTELLIGENCE SIGNAL.
AMBIENT NOISE: COMMUNICATONS INTERFERENCE PRESENT IN A SIGNAL PATH AT ALL TIMES. AMPLIFIER: AN ELECTRONIC COMPONENT THAT BOOSTS THE STRENGTH OR AMPLITUDE OF A TRANSMITTED, USUALLY ANALOG, SIGNAL; FUNCTIONALLY EQUIVALENT TO A REPEATER IN DIGITAL TRANSMISSIONS.
AMPLITUDE: MAGNITUDE OR SIZE. IN WAVE FORMS OR SIGNALS OCCURRING IN A DATA TRANSMISSION, A COMPLETE DEFINITION OF THE WAVE FORM CAN BE MADE IF THE VOLTAGE LEVEL IS KNOWN AT ALL TIMES. IN THIS CASE, THE VOLTAGE LEVEL IS CALLED THE AMPLITUDE.
AMPLITUDE MODULATION: A METHOD OF TRANSMISSION WHEREBY THE AMPLITUDE OF THE CARRIER FREQUENCY IS MODIFIED IN ACCORDANCE WITH THE BIT VALUE OF THE INTELLIGENCE SIGNAL.
ANALOG: REFERRING OR PERTAINING TO A SIGNALING TECHNIQUE IN WHICH A TRANSMISSION IS CONVEYED BY MODULATING (VARYING) THE FREQUENCY, AMPLITUDE, OR PHASE OF A CARRIER.
ANALOG LOOPBACK: TECHNIQUE FOR TESTING TRANSMISSION EQUIPMENT AND DEVICES THAT ISOLATE FAULTS TO THE ANALOG SIGNAL RECEIVING OR TRANSMITTING CIRCUITRY, WHERE A DEVICE, SUCH AS A MODEM, ECHOES BACK A RECEIVED (TEST) SIGNAL THAT IS THEN COMPARED WITH THE ORIGINAL SIGNAL.
ANALOG SIGNAL: SIGNAL IN THE FORM OF A CONTINUOUS WAVELIKE PATTERN REPRESENTING A PHYSICAL QUANTITY, SUCH AS VOLTAGE, WHICH REFLECTS VARIATIONS IN SOME QUANTITY, SUCH AS LOUDNESS OF THE HUMAN VOICE. ANALOG SIGNALING IS GENERIC TO THE PUBLIC SWITCHED TELEPHONE NETWORK (PSTN), AS WELL AS TO CERTAIN OTHER AUDIO-FREQUENCY AND RADIO-FREQUENCY FACILITIES.
ANALOG TRANSMISSION: TRANSMISSION OF A CONTINUOUSLY VARIABLE SIGNAL AS OPPOSED TO A DISCRETELY VARIABLE SIGNAL.
ANC: ALL NUMBER CALLING. CALLIN BY MEANS OF SEVEN DIGITS INSTEAD OF PREVIOUSLY USED TWO LETTERS PLUS FIVE DIGITS.
ANCILLARY EQUIPMENT: TERMINAL OR COMMUNICATIONS DEVICES NOT REQUIRED FOR THE PROVISION OF BASIC TELEPHONE SERVICE. ANSWERING MACHINES, CONFERENCING DEVICES, AND AUTOMATIC DIALERS ARE TYPES OF ANCILLARY EQUIPMENT.
ANGLE MODULATION: A FORM OF MODULATION IN WHICH THE ANGLE OF A SINE WAVE CARRIER IS VARIED.
ANSI: AMERICAN NATIONAL STANDARDS INSTITUTE. A PRIVATE U.S. STANDARDS BODY.
ANSWERBACK: A MANUALLY OR AUTOMATICALLY INITIATED RESPONSE FROM A TERMINAL THAT USUALLY INCLLUDES THE TERMINAL ADDRESS TO VERIFY THAT THE CORRECT TERMINAL HAS BEEN REACHED AND THAT IT IS OPERATIONAL.
ANTENNA: DEVICE USED TO TRANSMIT AND/OR RECEIVE RADIO WAVES. THE PHYSICAL DESIGN OF THE ANTENNA DETERMINES THE FREQUENCY RANGE OF TRANSMISSION/RECEPTION.
APERTURE: THE DIAMETER OF A PARABOLIC ANTENNA.
APL: A PROGRAMMING LANGUAGE. A PROBLEM-SOLVING PROGRAMMING LANGUAGE DESIGNED FOR REMOTE TERMINALS; IT OFFERS AN EXTENSIVE SET OF OPERATORS AND DATA STRUCTURES FOR HANDLING ARRAYS AND PERFORMING MATHEMATICAL FUNCTIONS.
APLT: ADVANCED PRIVATE LINE TERMINATION. PROVIDES THE PBX USER WITH ACCESS TO ALL THE SERVICES OF AN ASSOCIATED ENHANCED PRIVATE SWITCHED COMMUNICATIONS SERVICES (EPSCS) NETWORK. IT ALSO FUNCTIONS WHEN ASSOCIATED WITH A COMMON CONTROL SWITCHING ARRANGEMENT (CCSA)
NETWORK. APPEND: TO CHANGE OR ALTER A FILE OR PROGRAM BY ADDING TO THE END OF THE FILE OR PROGRAM.
APPLICATION LAYER: THE TOPE OF THE SEVEN-LAYER OSI MODEL, GENERALLY REGARDED AS OFFERING AN INTERFACE TO, AND LARGELY DEFINED BY, THE NETWORK USER; IN IBMS SNA, THE END-USER LAYER.
APPLICATION PROGRAM: SOFTWARE PROGRAMS IN A SYSTEM ARE USUALLY KNOWN AS "APPLICATION PROGRAMS" AND "SUPERVISORY PROGRAMS." APPLICATIONS PROGRAMS CONTAIN NO INPUT/OUTPUT CODING (EXCEPT IN THE FORM OF MACROINSTRUCTIONS THAT TRANSFER CONTROL TO THE SUPERVISORY PROGRAMS) AND ARE USUALLY UNIQUE TO ONE TYPE OF APPLICATION.
ARCHITECTURE: THE PHYSICAL INTER-RELATIONSHIP BETWEEN THE COMPONENTS OF A COMPUTER.
ARCHIVE: A PROCEDURE FOR TRANSFERRING INFORMATION FROM AN ONLINE STORAGE DISKETTE OR MEMORY AREA TO AN OFF-LINE STORAGE MEDIUM.
ARCNET: THE LOCAL NETWORKING PRODUCTS AND PHILOSOPHY DEVELOPED BY DATAPOINT CORPORATION.
ARPA: THE GENERIC NAME FOR SERVICES DESIGNED BY THE DEPARTMENT OF DEFENSE IN THE 1970S; IT IS NOW A DEFACTO STANDARD FOR NETWORKING MULTIVENDOR COMPUTERS RUNNING ON DIFFERING OPERATING SYSTEMS. INCLUDES FTP, SMTP, AND TELNET.
ARQ: AN ERROR CONTROL TECHNIQUE THAT REQUIRES RETRANSMISSION OF A DATA BLOCK THAT CONTAINS DETECTED ERRORS. A SPECIAL FORM, CALLED "GO-BACK-N," ALLOWS MULTIPLE BLOCKS TO BE ACKNOWLEDGED WITH A SINGLE RESPONSE. "STOP AND WAIT" REQUIRES AN ACKNOWLEDGMENT AFTER EACH BLOCK.
ARRAY: A NAMED, ORDERED COLLECTION OF DATA ELEMENTS THAT HAVE IDENTICAL ATTRIBUTES; OR AN ORDERED COLLECTION OF IDENTICAL STRUCTURES.
ARTIFICIAL INTELLIGENCE: THE CAPABILITY OF A COMPUTER TO PERFORM SUCH FUNCTIONS THAT ARE ASSOCIATED WITH HUMAN LOGIC AS REASONING, LEARNING, AND SELF-IMPROVEMENT.
ARTIFICIAL LANGUAGE: A CONVENTION BASED ON A SET OF RULES ESTABLISHED PRIOR TO ITS USAGE AND WITHOUT A PRECISE RELATIONSHIP TO THE USER APPLICATIONS IT WILL BE USED FOR.
ASCII: AMERICAN STANDARD CODE FOR INFORMATION INTERCHANGE. THIS IS A 7-BIT PLUS PARITY CODE ESTABLISHED BY ANSI TO ACHIEVE DATA SERVICES COMPATIBILITY. ALSO CALLED USASCII.
ASSEMBLER LANGUAGE: A SET OF COMMANDS THAT INCLUDES SYMBOLIC MACHINE LANGUAGE STATEMENTS IN WHICH THERE IS A ONE-TO-ONE CORRESPONDENCE WITH COMPUTER INSTRUCTIONS.
ASYNCHRONOUS: TRANSMISSION IN WHICH TIME INTERVALS BETWEEN TRANSMITTED CHARACTERS MAY BE OF UNEQUAL LENGTH. TRANSMISSION IS CONTROLLED BY START AND STOP BITS WHICH FRAME EACH CHARACTER.
ASYNCHRONOUS COMMUNICATIONS SOFTWARE: A SOFTWARE PACKAGE THAT, WHEN USED WITH A MODEM, ALLOWS A PC TO COMMUNICATE WITH INFORMATION SERVICES, DATABASES, OR HOSTS VIA ASYNCHRONOUS TRANSMISSION OVER THE PUBLIC TELEPHONE NETWORK.
ATB: ALL TRUNKS BUSY. CONDITION IN WHICH ALL TRUNKS IN A GROUP ARE ENGAGED.
ATTENUATION: A DECREASE IN THE POWER OF A RECEIVED SIGNAL DUE TO LOSS THROUGH LINES, EQUIPMENT, OR OTHER TRANSMISSION DEVICES. USUALLY MEASURED IN DECIBELS.
ATTIS: AT&T INFORMATION SYSTEMS; DIVISION OF AT&T TECHNOLOGIES THAT SUPPLIED AND MANUFACTURED CUSTOMER PREMISES EQUIPMENT CA. 1984-86.
AUDIO FREQUENCIES: FREQUENCIES THAT CORRESPOND TO THOSE THAT CAN BE HEARD BY THE HUMAN EAR (USUALLY 30HZ TO 20,000HZ).
AUDIOTEX: COMMUNICATIONS SYSTEM THAT ALLOWS A HOST COMPUTER TO PASS DATA TO A VOICE MAIL COMPUTER, A STORE-AND-FORWARD MECHANISM FOR DIGITIZED VOICE, WHERE IT IS INTERPRETED AND DELIVERED OVER THE TELEPHONE.
AUTO ANSWER: AUTOMATIC ANSWERING; CAPABILITY OF A TERMINAL, MODEM, COMPUTER, OR SIMILAR DEVICE TO RESPOND TO AN INCOMING CALL ON A DIAL-UP TELEPHONE LINE AND TO ESTABLISH A DATA CONNECTION WITH A REMOTE DEVICE WITHOUT OPERATOR INTERVENTION. ALLOWS UNATTENDED OPERATION FOR INCOMING DIAL-UP CALLS.
AUTO CALL: AUTOMATIC CALLING; A MACHINE FEATURE THAT ALLOWS A TRANSMISSION CONTROL UNIT OR A STATION TO AUTOMATICALLY INITIATE ACCESS TO A REMOTE SYSTEM OVER A SWITCHED LINE.
AUTO DIAL: AUTOMATIC DIALING. THE CAPABILITY OF A TERMINAL, MODEM, COMPUTER, OR SIMILAR DEVICE TO PLACE A CALL OVER THE SWITCHED TELEPHONE NETWORK AND ESTABLISH A CONNECTION WITHOUT OPERATOR INTERVENTION.
AUTOEXECUTE: AN OPERATING SYSTEM UTILITY THAT ALLOWS THE PROGRAM TO TO AUTOMATICALLY RUN A PROGRAM.
AUTOVON: AUTOMATIC VOICE NETWORK (U.S. MILITARY).
AVD CIRCUITS: ALTERNATE VOICE/DATA CIRCUITS THAT HAVE BEEN CONDITIONED TO HANDLE BOTH VOICE AND DATA TRAFFIC.
BABYPHONE: FEATURE ALLOWING CALLS TO AN OFF-HOOK TELEPHONE TO LISTEN TO ROOM NOISES, FOR EXAMPLE, TO CHECK IF A BABY IS CRYING.
BACKBONE NETWORK: THE PORTION OF A COMMUNICATIONS FACILITY THAT CONNECTS PRIMARY NODES; A PRIMARY SHARED COMMUNICATIONS PATH THAT SERVES MULTIPLE USERS VIA MULTIPLEXING AT DESIGNATED JUMPING-OFF POINTS.
BACKHAUL: THE TERRESTRIAL LINK BETWEEN AN EARTH STATION AND A SWITCHING OR DATA CENTER.
BACKUP: THE PROVISION OF FACILITIES, LOGICAL OR PHYSICAL, TO SPEED THE PROCESS OF RESTART AND RECOVERY FOLLOWING FAILURE.
BALANCED-TO-GROUND: WITH A TWO-WIRE CIRCUIT, THE IMPEDANCE-TO-GROUND ON ONE WIRE EQUALS THE IMPEDANCE-TO-GROUND ON THE OTHER WIRE. COMPARE WITH UNBALANCED-TO-GROUND, A PREFERABLE CONDITION FOR DATA TRANSMISSION.
BALUN: BALANCED/UNBALANCED. IN THE IBM CABLING SYSTEM, REFERS TO AN IMPEDANCE-MATCHING DEVICE USED TO CONNECT BALANCED TWISTED-PAIR CABLING WITH UNBALANCED COAXIAL CABLE.
BANDWIDTH: THE DIFFERENCE BETWEEN THE LOWEST AND HIGHEST FREQUENCIES TRANSMITTED THROUGH AN ANALOG CHANNEL (I.E., A CHANNEL CAPABLE OF TRANSMITTING SIGNALS IN THE RANGE FROM 300 TO 3300 HZ HAS A BANDWIDTH OF 3000 HZ); THE MAXIMUM DATA TRANSFER RATE OF A DIGITAL CHANEL (A T1 CHANNEL HAS A BANDWIDTH OF 1.544 MBPS).
BASEBAND: TRANSMISSION OF A SIGNAL AT ITS ORIGINAL FREQUENCIES, WITHOUT MODULATION.
BASR: BUFFERED AUTOMATIC SEND/RECEIVE.
BATCH MODE: APPLICATION PROGRAMS RUN ON THE COMPUTER ONE AT A TIME. FOR EXAMPLE, FINANCIAL TRANACTIONS MAY BE ACCUMULATED FOR A WEEK, THEN FED AS A GROUP INTO THE COMPUTER TO UPDATE THE GENERAL LEDGER FILES AND TO PRODUCE ACCOUNTING REPORTS.
BAUD: A MEASURE OF SIGNALING SPEED EQUAL TO THE NUMBER OF DISCRETE CONDITIONS OR SIGNAL EVENTS PER SECOND.
BAUD RATE: A MEASURE OF SIGNALING SPEED EQUAL TO THE NUMBER OF DISCRETE CONDITIONS OR SIGNAL EVENTS PER SECOND.
BAUDOT: A CODE FOR THE TRANSMISSION OF TELEPRINTER DATA, IN WHICH FIVE BITS REPRESENT ONE CHARACTER.
BCC: BLOCK CHECK CHARACTER. THE RESULT OF A TRANSMISSION VERFICATION ALGORITHM ACCUMULATED OVER A TRANSMISSION BLOCK, AND NORMALLY APPENDED AT THE END OF THE BLOCK; E.G.: CRC OR LRC.
BCD: BINARY CODED DECIMAL. A BINARY-CODED ALPHANUMBERIC NOTATION IN WHICH EACH OF THE DECIMAL DIGITS IS REPRESENTED BY A BINARY NUMBERAL, E.G., IN BINARY CODE DECIMAL NOTATION THAT USES THE WEIGHTS 8-4-2-1, THE NUMBER 23 IS REPRESENTED 0010 0011.
BDLC: BURROUGHS DATA LINK CONTROL. A BIT-ORIENTED PROTOCOL SIMILAR TO HIGH-LEVEL DATA LINK CONTROL (HDLC).
BEAM WIDTH: ANGULAR WIDTH OF AN ANTENNA RADIATION PATTERN, OR BEAM, WITHIN WHICH THE RADIATION EXCEEDS SOME PROPORTION OF THE MAXIMUM.
BENCHMARK: A PORINT OF REFERENCE FROM WHICH MEASUREMENTS CAN BE MADE; INVOLVES THE USE OF TYPICAL PROBLEMS FOR COMPARING PERFORMANCE AND IS OFTER USED IN DETERMINING WHICH COMPUTER CAN BEST SERVE A PARTICULAR APPLICATION.
BER: BIT ERROR RATE. IN DATA COMMUNICATIONS TESTING, THE RATIO BETWEEN THE TOTAL NUMBER OF BITS TRANSMITTED IN A GIVEN MESSAGE AND THE NUMBER OF BITS IN THAT MESSAGE RECEIVED IN ERROR. A MEASURE OF THE QUALITY OF A DATA TRANSMISSION, USUALLY EXPRESSED AS A NUMBER REFERRED TO A POWER OF 10; E.G, 1 IN 10 OVER 5.
BERT: BIT ERROR RATE TEST. A TEST CONDUCTED BY TRANSMITTING A KNOWN PATTERN OF BITS (COMMONONLY 63,511, OR 2047 BITS IN LENGTH), COMPARING THE PATTERN RECEIVED WITH THE PATTERN TRANSMITTED, AND COUNTING THE NUMBER OF BITS RECEIVED IN ERROR.
BETA TEST: THE STAGE AT WHICH A NEW PRODUCT IS TESTED UNDER ACTUAL CONDITIONS.
BIDIRECTIONAL PRINTING: PRINTING OUTPUT IN TWO DIRECTIONS - LEFT TO RIGHT AND RIGHT TO LEFT. THIS IS FASTER AND SAVES WEAR ON THE PRINTER.
BINARY: THE BASE-2 NUMBER SYSTEM USING ONLY THE SYMBOLS 0 AND 1. SINCE 0 AND 1 CAN BE REPRESENTED AS ON AND OFF, OR NEGATIVE AND POSITIVE CHARGES, MOST COMPUTERS DO THEIR CALCULATIONS IN BINARY.
BINARY SYNCHRONOUS COMMUNICATIONS: AN IBM DEFINED BYTE CONTROLLED COMMUNICATIONS PROTOCOL, USING CONTROL CHARACTERS AND SYNCHRONIZED TRANSMISSION OF BINARY CODED DATA BETWEEN STATIONS. ALSON CALLED BISYNC. SIMILAR TO ANSI X3.28 AND ISO 1745.
BIT: AN ABBREVIATION FOR BINARY DIGIT. IT IS THE AMOUNT OF INFORMATION DERIVED FROM KNOWLEDGE OF THE OCCURRENCE OF ONE OF TWO EQUIPROBABLE EXCLUSIVE EVENTS, E.G., 0 OR 1. THE SMALLEST UNIT OF INFORMATION IN THE BINARY SYSTEM OF NOTATION.
BIT RATE: THE SPEED AT WHICH BITS ARE TRANSMITTED, USUALLY EXPRESSED IN BITS PER SECOND (BPS).
BIT-MAPPED: REFERS TO A DISPLAY SCREEN ON WHICH A CHARACTER OR IMAGE IS GENERATED AND REFRESHED ACCORDING TO A BINARY MATRIX (BIT MAP) AT A SPECIFIC LOCATION IN MEMORY.
BIT-ORIENTED: DESCRIBES A COMMUNICATIONS PROTOCOL OR TRANSMISSION PROCEDURE WHERE CONTROL INFORMATION IS ENCODED IN FIELDS OF ONE OR MORE BITS. ORIENTED TOWARD FULL-DUPLEX LINK OPERATION.
BITS PER SECOND: BPS. BASIC UNIT OF MEASUREMENT FOR SERIAL DATA TRANSMISSION CAPACITY; ABBREVIATED A K BPS, OR KILOBIT/S, FOR THOUSANDS OF BITS PER SECOND; M BPS, OR MEGABIT/S, FOR MILLIONS OF BITS PER SECOND; G BITS, OR GIGABIT/S FOR BILLIONS OF BITS PER SECOND; T BPS, OR TERABIT/S, TRILLIONS OF BITS PER SECOND.
BLANKING INTERVAL: THE AREA IN A VIDEO SIGNAL THAT FALLS BETWEEN FRAMES. IT IS OFTEN USED TO ACCOMMODATE DATA INCLUDING SYNCHRONIZING INFORMATION.
BLERT: BLOCK ERROR RATE TEST/TESTER. A TEST CONDUCTED BY TRANSMITTING A KNOWN BLOCKED BIT PATTERN, COMPARING THE PATTERN RECEIVED WITH THE PATTERN TRANSMITTED, AND COUNTING THE NUMBER OF BLOCKS CONTAINING ERRORED BITS.
BLOCK: A GROUP OF CHARACTERS TRANSMITTED AS A UNIT, OVER WHICH A CODING PROCEDURE IS USUALLY APPLIED FOR SYNCHRONIZATION AND/ OR ERROR CONTROL PURPOSES.
BLOCK: A STRING OF RECORDS, WORDS, OR CHARACTERS TREATED AS A LOGICAL ENITY. BLOCKS ARE SEPARATED BY INTERBLOCK GAPS, AND EACH BLOCK MAY CONTAIN ONE OR MORE RECORDS.
BLOCK CHECK CHARACTER: A CONTROL CHARACTER APPENDED TO BLOCKS IN CHARACTER-ORIENTED PROTOCOLS. USED FOR DETERMINING IF THE BLOCK WAS RECEIVED IN ERROR IN LONGITUDINAL AND CYCLIC REDUNDANCY CHECKING.
BLOCK ERROR RATE: IN DATA COMMUNICATIONS TESTING, THE RATIO BETWEEN THE TOTAL NUMBER OF BLOCKS TRANSMITTED IN A GIVEN MESSAGE AND THE NUMBER OF BLOCKS IN THE MESSAGE RECEIVED IN ERROR; A MEASURE OF THE QUALITY OF A DATA TRANSMISSION.
BLOCK LENGTH: A MEASURE OF THE SIZE OF A BLOCK, USUALLY SPECIFIED IN UNITS SUCH AS RECORDS, WORDS, COMPUTER WORDS, OR CHARACTERS.
BNA: BURROUGHS NETWORK ARCHITECTURE. A COMMUNICATIONS ARCHITECTURE DEVELOPED BY BURROUGHS.
BOC: BELL OPERATING COMPANY. ANY OF 22 LOCAL TELEPHONE COMPANIES SPUN OFF FROM AT&T AS A RESULT OF DIVESTITURE.
BOC: BELL OPERATING COMPANY.
BOP: BIT ORIENTED PROTOCOL. PROTOCOL USING STANDARD FRAME FORMAT ZERO INSERTION AND DELETION, CRC-CCITT, FLAG, ABORT, AND IDLE UNIQUE CONTROL BIT PATTERNS AND SYNCRONOUS TRANSMISSION
BPS: BITS PER SECOND TRANSMITTED OR RECEIVED.
BREAKOUT BOX: A DEVICE THAT ALLOWS ACCESS TO INDIVIDUAL POINTS ON A PHYSICAL INTERFACE CONNECTOR (E.G. EIA RS-232-C) FOR TESTING AND MONITORING.
BRIDGE: 1) TO CONNECT A LOAD ACROSS A CIRCUIT. 2) THE CONNECTION ITSELF THAT ALLOWS THE INTERCONNECTION OF LANS, PERMITTING COMMUNICATION BETWEEN DEVICES ON SEPARATE NETWORKS.
BROADBAND: 1) TRANSMISSION EQUIPMENT AND MEDIA THAT CAN SUPPORT A WIDE RANGE OF ELECTROMAGNETIC FREQUENCIES. 2) ANY VOICE COMMUNICATIONS CHANNEL HAVING A BANDWIDTH GREATER THAN A VOICE GRADE TELECOMMUNICATIONS CHANNEL; SOMETIMES USED SYNONYMOUSLY WITH WIDEBAND. 3) TYPICALLY THE TECHNOLOGY OF CATV (Q.V.) TRANSMISSION, AS APPLIED TO DATA COMMUNICATIONS; EMPLOYS COAXIAL CABLE AS THE TRANSMISSION MEDIUM AND RADIO FREQUENCY CARRIER SIGNALS IN THE 50 M HZ TO 500M HZ RANGE.
BROADCAST: A TRANSMISSION TO MULTIPLE RECEIVING LOCATIONS SIMULTANEOUSLY. A BROADCAST CAN BE MADE, FOR EXAMPLE, OVER A MULTIPOINT LINE TO ALL TERMINALS THAT SHARE THE LINE, OR OVER A RADIO OR TELEVISION CHANNEL TO ALL RECEIVERS TUNED TO THAT CHANNEL.
BSC: BINARY SYNCHRONOUS COMMUNICATIONS. AN IBM DEFINED BYTE CONTROLLED COMMUNICATIONS PROTOCOL, USING CONTROL CHARACTERS AND SYNCHRONIZED TRANSMISSION OF BINARY CODED DATA BETWEEN STATIONS. ALSO CALLED BISYNC. SIMILAR TO ANSI X3.28 AND ISO 1745.
BTAM: BASIC TELECOMMUNICATIONS ACCESS METHOD. IBM'S LOWEST LEVEL I/O MACRO-ROUTINE SUPPORT FOR PROVIDING COMMUNICATIONS PROGRAMS ON A HOST COMPUTER.
BUFFER: A STORAGE DEVICE USED TO COMPENSATE FOR THE DIFFERENCE IN THE RATE OF DATA FLOW WHEN TRANSMITTING DATA FROM ONE DEVICE TO ANOTHER.
BURST: IN DATA COMMUNICATIONS, A SEQUENCE OF SIGNALS COUNTED AS ONE UNIT IN ACCORDANCE WITH SOME SPECIFIC CRITERION OR MEASURE.
BUS: 1) PHYSICAL TRANSMISSION PATH OR CHANNEL. TYPICALLY AN ELECTRICAL CONNECTION, WITH ONE OR MORE CONDUCTORS, WHEREIN ALL ATTACHED DEVICES RECEIVE ALL TRANSMISSIONS AT THE SAME TIME. 2) LOCAL NETWORK TOPOLOGY, SUCH AS USED IN ETHERNET AND THE TOKEN BUS, WHERE ALL NETWORK NODES LISTEN TO ALL TRANSMISSIONS, SELECTING CERTAIN ONES BASED ON ADDRESS IDENTIFICATION. INVOLVES SOME TYPE OF CONTENTION-CONTROL MECHANISM FOR ACCESSING THE BUS TRANSMISSION MEDIUM.
BYTE: A BINARY ELEMENT STRING OF 8 BITS, USUALLY OPERATED UPON AS A UNIT.
CAD/CAM: COMPUTER-AIDED DESIGN/COMPUTER-AIDED MANUFACTURING; SYSTEMS THAT AID IN THE DESIGN OF PRODUCTS AND THEN TRANSFER THE INFORMATION TO CONTROL MANUFACTURING EQUIPMENT.
CARRIER: A CONTINUOUS FREQUENCY CAPABLE OF BEING MODULATED OR IMPRESSED WITH A SIGNAL.
CARRIER: CXR. A SIGNAL OF KNOWN CHARACTERISTICS (FOR EXAMPLE, FREQUENCY) THAT IS ALTERED (MODULATED) TO TRANSMIT INFORMATION. KNOWING THE EXPECTED SIGNAL, THE RECEIVING TERMINAL INTERPRETS ANY CHANGE IN SIGNAL AS INFORMATION. CHANGES TO THE SIGNAL MADE BY OUTSIDE INFLUENCES (NOISE) CAN CAUSE THE RECEIVING TERMINAL TO MISINTERPRET THE INFORMATION TRANSMITTED.
CARRIER FREQUENCY: FREQUENCY OF THE CARRIER WAVE THAT IS MODULATED TO TRANSMIT SIGNALS.
CARRIER SIGNALING: ANY OF THE SIGNALING TECHNIQUES USED IN MULTICHANNEL CARRIER TRANSMISSION. THE MOST COMMONLY USED TECHNIQUES ARE IN-BAND SIGNALING, OUT-OF-BAND SIGNALING, AND SEPARATE CHANNEL SIGNALING.
CARRIER SYSTEM: MEANS OF OBTAINING A NUMBER OF CHANNELS OVER A SINGLE PATH BY MODULATING EACH CHANNEL ON A DIFFERENT CARRIER FREQUENCY AND DEMODULATING AT THE RECEIVING POINT TO RESTORE THE SIGNALS TO THEIR ORIGINAL FREQUENCY.
CARTERFONE DECISION: LANDMARK 1968 FCC DECISION THAT FIRST PERMITTED THE ELECTRICAL CONNECTION OF CUSTOMER-OWNED TERMINAL EQUIPMENT OT THE TELEPHONE NETWORK.
CATV: COMMUNITY ANTENNA TELEVISION. 1) WHERE TELEVISION RECEPTION IS POOR, SIGNALS CAN BE RECEIVED AT A SELECTED SITE BY SENSITIVE, DIRECTIONAL ANTENNAS AND THEN TRANSMITTED TO SUBSCRIBERS VIA A CABLE NETWORK. ADDITIONAL CHANNELS, NOT NORMALLY AVAILABLE IN THAT AREA, CAN ALSO BE TRANSMITTED. 2) DATA COMMUNICATIONS BASED ON RADIO FREQUENCY (RF) TRANSMISSION MEDIUM. CATV OFFERS MULTIPLE FREQUENCY- DDIVIDED CHANNELS.
CCIS: COMMON CHANNEL INTEROFFICE SIGNALING. AN ELECTRONIC MEANS OF SIGNALING BETWEEN ANY TWO SWITCHING SYSTEMS INDEPENDENT OF THE VOICE PATH. THE USE OF CCIS MAKES POSSIBLE NEW CUSTOMER SERVICE, VERSATILE NETWORK FEATURES, MORE FLEXIBLE CALL ROUTING, AND FASTER CALL CONNECTIONS.
CCITT: COMITE CONSULTATIF INTERNATIONALE DE TELEGRAPHIC TELEPHONIE. AN INTERNATIONAL CONSULTATIVE COMMITTEE WICH SETS COMMUNICATION STANDARDS. THIS COMMITTEE IS RESPONSIBLE TO THE ITU WHICH IS A U.N. TREATY ORGANIZATION.
CCTV: CLOSED CIRCUIT TELEVISON. TELEVISION TRANSMISSION VIA DIRECT LINK BETWEEN TWO POINTS, AS OPPOSED TO BROADCAST TRANSMISSION TO MANY RECEIVING LOCATIONS.
CEN: EUROPEAN STANDARDS INSTITUTE (COMITE EUROPEEN DE NORMALISATION).
CENLEC: EUROPEAN ELECTRICAL STANDARDS INSTITUTE (COMITE EUROPEEN DE NORMALISATION ELECTRIQUE).
CENTREX: CENTRAL EXCHANGE; THE TELEPHONE COMPANY'S TERMINATION POINT FOR MULTIPLE LINES FROM CUSTOMERS. SWITCHING FACILITIES AT THE CENTRAL EXCHANGE ALLOW INTERCONNECTION OF THE VARIOUS LINES OR CIRCUITS.
CHANNEL: THE PART OF A COMMUNICATIONS SYSTEM THAT CONNECTS A COMMUNICATIONS SOURCE TO A MESSAGE SINK.
CHANNEL CAPACITY: A TERM WHICH EXPRESSES THE MAXIMUM DATA RATE WHICH CAN BE HANDLED BY THE CHANNEL.
CHARACTER: LETTER, FIGURE, NUMBER, PUNCTUATION, OR OTHER SIGN CONTAINED IN A MESSAGE. BECAUSE DATA IS HANDLED AND TRANSFERRED AS A SERIES OF CHARACTERS, THE TERM IS ALSO USED TO MEAN ONE BIT PATTERN IN A SPECIFIC DATA CODE.
CHARACTER ORIENTED PROTOCOL: A PROTOCOL IN WHICH A SPEIFIC SET FO COMMUNICATIONS CONTROL CHARACTER SEQUENCES CONFIGURE AND MANAGE THE DATA LINK.
CHIP: THE SUBSTRATE UPON WHICH VLSI/LSI CIRCUITS ARE FABRICATED;- SOMETIMES USED TO REFER TO THE CIRCUITS ON THE CHIP THEM- SELVES.
CICS: CUSTOMER INFORMATION CONTROL SYSTEM. AN IBM TELEPROCESSING MONITOR.
CIRCUIT: 1) MEANS OF TWO-WAY COMMUNICATION BETWEEN TWO OR MORE POINTS. 2) A GROUP OF ELECTRICAL/ELECTRONIC COMPONENTS CONNECTED TO PERFORM A SPECIFIC FUNCTION.
CIRCUIT SWITCHING: TEMPORARY DIRECT CONNECTION OF TWO OR MORE CHANNELS BETWEEN TWO OR MORE POINTS IN ORDER TO PROVIDE THE USER WITH EXCLUSIVE USE OF AN OPEN CHANNEL WITH WHICH TO EXCHANGE INFORMATION. A DISCRETE CIRCUIT PATH IS SET UP BETWEEN THE INCOMING AND OUTGOING LINES, IN CONTRAST TO MESSAGE SWITCHING AND PACKET SWITCHING, IN WHICH NO SUCH PHYSICAL PATH IS ESTABLISHED. ALSO CALLED LINE SWITCHING.
CLADDING: IN FIBER OPTIC CABLE, A COLORED, LOW REFRACTIVE INDEX MATERIAL THAT SURROUNDS THE CORE AND PROVIDES OPTICAL INSULATION AND PROTECTION TO THE CORE.
CLEAR TO SEND: A TIME DELAY INSERTED AFTER A DATA TERMINAL EQUIPMENT REQUESTS TO SEND DATA TO ALLOW THE MODEM TO TURN CARRIER ON AND TO ESTABLISH EQUALIZATION AND SYNCHRONIZATION. ALSO KNOWN AS RTS-CTS DELAY AND TURNAROUND DELAY.
CLOCKING: REPETITIVE, REGULARLY TIMED SIGNALS USED TO CONTROL SYNCHRONOUS TRANSMISSIONS.
CLUSTER CONTROLLER: A DEVICE THAT HANDLES THE REMOTE COMMUNICATIONS PROCESSING FOR MULTIPLE (USUALLY DUMB) TERMINALS OR WORKSTATIONS.
CMOS: COMPLEMENTARY METAL-OXIDE SEMICONDUCTOR (LOGIC CIRCUIT).
CO: CENTRAL OFFICE. LOCATION WHERE COMMUNICATIONS COMMON CARRIERS TERMINATE CUSTOMER LINES AND HOUSE THE EQUIPMENT THAT INTERCONNECTS THESE LINES.
CO-PROCESSOR: AN ADDITIONAL CENTRAL LOGIC UNIT WHICH PERFORMS SPECIFIC TASKS WHILE THE MAIN UNIT EXECUTES ITS PRIMARY TASKS. FREQUENTLY, THESE CHIPS ARE ADDED TO SPEED UP MATHEMATICAL TASKS OR PERFORM I/O FUNCTIONS.
COBOL: COMMON BUSINESS ORIENTED LANGUAGE. LANGUAGE USED IN PROGRAMMING COMPUTERS.
CODE: THE CONVENTIONS SPECIFYING HOW DATA MAY BE REPRESENTED IN A PARTICULAR SYSTEM.
CODEC: CODER-DECODER DEVICE USED TO CONVERT ANALOG SIGNALS, SUCH AS SPEECH, MUSIC, OR TELEVISION, TO DIGITAL FORM FOR TRANSMISSION OVER A DIGITAL MEDIUM, AND BACK AGAIN TO THE ORIGINAL ANALOG FORM. ONE IS REQUIRED AT EACH END OF THE CHANNEL.
COMMON CARRIER: AN ORGANIZATION IN THE BUSINESS OF PROVIDING REGULATED TELEPHONE, TELEGRAPH, TELEX, AND DATA COMMUNICATIONS SERVICES.
COMMUNICATION: TRANSMISSION OF INTELLIGENCE BETWEEN POINTS OF ORIGIN AND RECEPTION, WITHOUT ALTERATION OF SEQUENCE OR STRUCTURE OF THE CONTENT.
COMMUNICATION LINE: ANY MEDIUM, SUCH AS A WIRE OR A TELEPHONE CIRCUIT, THAT CONNECTS REMOTE STATIONS FOR THE PURPOSE OF TRANSMITTING/ RECEIVING INFORMATION.
COMMUNICATIONS CONTROLLER: DEDICATED COMPUTER WITH SPECIAL PROCESSING CAPABILITIES FOR ORGANIZING AND CHECKING DATA AND HANDLING INFORMATION TRAFFIC TO AND FROM MANY REMOTE TERMINALS OR COMPUTERS, INCLUDING FUNCTIONS SUCH AS MESSAGE SWITCHING.
COMMUNICATIONS SATELLITE: EARTH SATELLITE DESIGNED TO ACT AS A TELECOMMUNICATIONS RADIO RELAY AND USUALLY POSITIONED IN GEOSYNCHRONOUS ORBIT 35,800 KILOMETERS (23,000 MILES) ABOVE THE EQUATOR SO THAT IT APPEARS TO BE STATIONARY IN SPACE.
COMPRESSION: THE APPLICATION OF ANY OF SEVERAL TECHNIQUES THAT REDUCE THE NUMBER OF BITS REQUIRED TO REPRESENT INFORMATION IN DATA STORAGE, THEREFORE CONSERVING BANDWIDTH AND/OR MEMORY.
COMPUTER NETWORK: AN INTERCONNECTION OF COMPUTER SYSTEMS, TERMINALS, COMMUNICATONS FACILITIES, AND DATA COLLECTING DEVICES.
COMSAT: COMMUNICATIONS SATELLITE CORPORATION, A PRIVATE U.S. COMPANY ESTABLISHED BY STATUTE AS THE EXCLUSIVE INTERNATIONAL SATELLITE CARRIER AND REPRESENTING THE U.S. IN INTELSAT.
CONCENTRATOR: A COMMUNICATIONS DEVICE THAT PROVIDES COMMUNICATION CAPABILITY BETWEEN MANY LOW-SPEED CHANNELS AND ONE OR MORE HIGH-SPEED CHANNELS.
CONDITIONING: THE ADDITION OF EQUIPMENT TO LEASED VOICE-GRADE LINES, TO PROVIDE SPECIFIED MINIMUM VALUES OF LINE CHARACTERISTICS REQUIRED FOR DATA TRANSMISSION.
CONDITIONING: PROCEDURE TO MAKE TRANSMISSION IMPAIRMENTS OF A CIRCUIT LIE WITHIN CERTAIN SPECIFIED LIMITS AND TYPICALLY USED ON TELEPHONE LINES LEASED FOR DATA TRANSMISSION TO IMPROVE THE POSSIBLE TRANSMISSION SPEED. TOW TYPE ARE USED: C CONDITIONING AND D CONDITIONING.
CONTENTION: A CONDITION ON A COMMUNICATIONS CHANNEL IN WHICH TWO OR MORE STATIONS TRY TO TRANSMIT AT THE SAME TIME.
CONTENTION: METHOD OF LINE CONTROL IN WHICH THE TERMINALS REQUEST TO TRANSMIT. IF THE CHANNEL IN QUESTION IS FREE, TRANSMISSION PROCEEDS; IF IT IS NOT FREE, THE TERMINAL WILL HAVE TO WAIT UNTIL IT BECOMES FREE. A QUEUE OF CONTENTION REQUESTS CAN BE BUILT UP BY A COMPUTER, AND THIS QUEUE CAN EITHER BE ORGANIZED IN A PREARRANGED SEQUENCE OR IN THE SEQUENCE IN WHICH REQUEST ARE MADE.
CONTINUITY CHECK: IN COMMON-CHANNEL SIGNALING, A TEST PERFORMED TO CHECK THAT A PATH EXISTS FOR SPEECH OR DATA TRANSMISSION.
CONTROL CHARACTER: A CHARACTER WHOSE OCCURRENCE IN A PARTICULAR CONTEXT INITIATES, MODIFIES, OR STOPS A CONTROL FUNCTION.
COP: CHARACTER ORIENTED PROTOCOL. A PROTOCOL IN WHICH A SPECIFIC SET OF COMMUNICATION CONTROL CHARACTER SEQUENCES CONFIGURE AND MANAGE THE DATA LINK.
CPM: CP/M. CONTROL PROGRAM/MICROCOMPUTER; A FAMILY OF OPERATING SYSTEMS DEVELOPED BY DIGITAL RESEARCH, INC.
CRC: CYCLIC REDUNDANCY CHECK. AN ERROR DETECTION SCHEME IN WHICH THE BCC IS GENERATED BY TAKING THE REMAINDER AFTER DIVIDING ALL THE SERIALIZED BITS IN A BLOCK OF DATA BY A PRESET NUMBER.
CRT: CATHODE-RAY TUBE. A DEVICE SIMILAR TO A TELEVISION PICTURE TUB, USED TO DISPLAY TEXTUAL AND GRAPHIC INFORMATION.
CSMA: CARRIER SENSE MULTIPLE ACCESS. A LOCAL AREA NETWORK ACCESS TECHNIQUE IN WHICH MULTIPLE STATIONS CONNECTED TO THE SAME CHANNEL ARE ABLE TO SENSE TRANSMISSION ACTIVITY ON THAT CHANNEL AND TO DEFER THE INITIATION OF TRANSMISSION WHILE THE CHANNEL IS ACTIVE. SIMILAR TO CONTENTION ACCESS.
CSMA/CD: CARRIER SENSE MULTIPLE ACCESS WITH COLLISION DETECTION. A REFINEMENT OF CSMA IN WHICH STATIONS ARE ABLE TO DETECT THE INTERFERENCE CAUSED BY SIMULTANEOUS TRANSMISSIONS BY TWO OR MORE STATIONS (COLLISIONS) AND TO RETRANSMIT COLLIDING MESSAGES IN AN ORDERLY MANNER.
CSU: CHANNEL SERVICE UNIT. A COMPONENT OF CUSTOMER PREMISES EQUIPMENT (CPE) USED TO TERMINATE A DIGITAL CIRCUIT, SUCH AS A DDS OR T1 FACILITY, AT THE CUSTOMER SITE. PERFORMS CERTAIN LINE-CONDITIONING FUNCTIONS, ENSURES NETWORK PER FCC RULES, AND RESPONDS TO LOOPBACK COMMANDS FROM THE CENTRAL OFFICE. ALSO, ENSURES PROPER 1'S DENSITY IN A TRNAMSITTED BITSTREAM AND PERFORMS BIPOLAR VIOLATION CORRECTION.
CTS: CLEAR TO SEND. A TIME DELAY INSERTED AFTER A DATA TERMINAL EQUIPMENT REQUESTS TO SEND DATA TO ALLOW THE MODEM TO TURN CARRIER ON AND TO ESTABLISH EQUALIZATION AND SYNCHRONIZATION ALSO KNOW AS RTS-CTS DELAY AND TURNAROUND DELAY.
CURRENT LOOP: A TRANSMISSION TECHNIQUE THAT RECOGNIZES CURRENT FLOWS, RATHER THAN VOLTAGE LEVELS. IT HAS TRADITIONALLY BEEN USED IN TELETYPEWRITER NETWORKS INCORPORATING BATTERIES AS THE TRANSMISSION POWER SOURCE.
CYCLIC REDUNDANCY CHECK: AN ERROR DETECTION SCHEME IN WHICH THE BCC IS GENERATED BY TAKING THE REMAINDER AFTER DIVIDING ALL THE SERIALIZED BITS IN A BLOCK OF DATA BY A PRESET NUMBER.
DAISYCHAINING: THE CONNECTION OF MULTIPLE DEVICES IN A SERAIL FASHION. AN ADVANTAGE OF DAISYCHAINING IS A SAVINGS IN TRANSMISSION FACILITIES. A DISADVANTAGE IS THAT IF A DEVICE MALFUNCTIONS ALL OF THE DEVICES DAISYCHAINED BEHIND IT ARE DISABLED.
DATA COMMUNICATIONS: THE INTERCHANGE OF DATA MESSAGES FROM ONE POINT TO ANOTHER OVER COMMUNICATIONS CHANNELS.
DATA COMMUNICATIONS EQUIPMENT: THE EQUIPMENT WHICH PROVIDES THE FUNCTIONS OF INTERFACING BETWEEN DATA TERMINAL EQUIPMENT AND A COMMUNICATIONS CHANNEL DCE IS NORMALLY A MODEM.
DATA LINK: A TRANSMISSION PATH DIRECTLY CONNECTING TWO OR MORE STATIONS. (A STATION MAY BE A TERMINAL, TERMINAL CONTROLLER, FRONT END PROCESSOR, OR OTHER TYPE OF DIGITAL EQUIPMENT.)
DATA LINK: ANY SERIAL DATA COMMUNICATIONS TRANSMISSION PATH, GENERALLY BETWEEN TWO ADJACENT NODES OR DEVICES AND WITHOUT ANY INTERMEDIATE SWITCHING NODES.
DATA LINK CONTROL: A UNIFORM DISCIPLINE FOR THE TRANSMISSION OF DATA OVER A SINGLE COMMUNICATIONS LINK. DATA LINK
ESCAPE: THE FIRST CONTROL CHARACTER OF TWO-CHARACTER SEQUENCE USED EXCLUSIVELY TO PROVIDE SUPPLEMENTARY LINE-CONTROL SIGNALS.
DATA SET: (1) A MODEM. (2) A COLLECTION OF DATA RECORDS, WITH A LOGICAL RELATION OF ONE TO ANOTHER.
DATA TERMINAL EQUIPMENT: THE EQUIPMENT COMPRISING THE DATA SOURCE, DATA SINK, OR BOTH.
DATA TRANSMISSION: THE SENDING OF DATA FROM ONE PLACE FOR RECEPTION ELSEWHERE.
DATAGRAM: PACKET OF DATA WHICH CAN BE DELIVERED THROUGH A PACKET SWITCHED SYSTEM WITHOUT REFERENCE TO PREVIOUS PACKETS ADDRESSED TO THE SAME DESTINATION.
DATAPHONE DIGITAL SERVICE: A COMMUNICATIONS SERVICE OF AT&T IN WHICH DATA IS TRANSMITTED IN DIGITAL RATHER THAN ANALOG FORM, THUS ELIMINATING REQUIREMENTS FOR MODEM DEVICES.
DCE: DATA COMMUNICATIONS EQUIPMENT. THE EQUIPMENT WHICH PROVIDES THE FUNCTIONS OF INTERFACING BETWEEN DATA TERMINAL EQUIPMENT AND A COMMUNICATION CHANNEL. DCE IS NORMALLY A MODEM.
DDCMP: DIGITAL DATA COMMUNICATIONS MESSAGE PROTOCOL. THE DEC DATA LINK LAYER COMMUNICATIONS PROTOCOL USED TO TRANSMIT MESSAGES OVER SYNCHRONOUS, ASYNCHRONOUS, OR PARALLEL FULL OR HALF DUPLEX COMMUNICATIONS LINES.
DDD: DIRECT DISTANCE DIALING. A TELEPHONE EXCHANGE SERVICE WHICH ENABLES A USER TO DIAL TELEPHONE NUMBERS OUTSIDE HIS LOCAL CALLING AREA WITHOUT OPERATOR ASSISTANCE.
DDS: DATAPHONE DIGITAL SERVICE. A COMMUNICATIONS SERVICE OF AT&T IN WHICH DATA IS TRANSMITTED IN DIGITAL RATHER THAN ANALOG FORM, THUS ELIMINATING REQUIREMENTS FOR MODEM DEVICES
DECIBEL: (DB) UNIT FOR MEASURING RELATIVE STRENGH OF SIGNAL PARAMETER SUCH AS POWER OR VOLTAGE. THE NUMBER OF DECIBELS IS 10 TIME THE LOGARITHM (BASE 10) OF THE RATIO OF THE POWER OF TWO SIGNALS, OR RATIO OF THE POWER OF ONE SIGNAL TO A REFERENCE LEVEL.
DECNET: A DIGITAL EQUIPMENT CORP. PROGRAM PRODUCT BUILT ON DNA CONCEPTS IMPLEMENTING DISTRIBUTED PROCESSING FUNCTIONS ON DEC MACHINES.
DELIMITER: IN DATA COMMUNICATIONS, A CHARACTER THAT SEPARATES AND ORGANIZES ELEMENTS OF DATA.
DEMARC: DEMARCATION POINT BETWEEN CARRIER EQUIPMENT AND CUSTOMER- PREMISES EQUIPMENT (CPE); USUALLY A TERMINAL BLOCK.
DEMODULATION: THE PROCESS OF RETRIEVING AND DIGITIZING AN ORIGINAL INTELLIGENCE SIGNAL FROM A MODULATED (ANALOG) CARRIER WAVE.
DES: DATA ENCRYPTION STANDARD. A CRYPTOGRAPHIC ALGORITHM DESIGNED BY THE NATIONAL BUREAU OF STANDARDS (NOW THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY) TO ENCYPHER AND DECIPHER DATA USING A 64-BIT KEY.
DIAGNOSTICS: SOFTWARE ROUTINES USED TO CHECK EQUIPMENT MALFUNCTIONS AND TO PINPOINT FAULTY COMPONENTS.
DIGITAL: REFERRING TO COMMUNICATIONS PROCEDURES, TECHNIQUES, AND EQUIPMENT WHEREBY INFORMATION IS ENCODED AS EITHER BINARY "1" OR "0"; THE REPRESENTATION OF INFORMATION IN DISCRETE BINARY FORM, DISCONTINUOUS IN TIME, AS OPPOSED TO THE ANALOG REPRESENTATION OF INFORMATION IN VARIABLE, BUT CONTINUOUS, WAVEFORMS.
DIP: DUAL IN-LINE PACKAGE.
DIP SWITCH: A DUAL IN-LINE SWITCH; ALLOWS THE USER TO SET CURRENT PATHS ON OR OFF; THEY ARE FREQUENTLY USED TO RECONFIGURE MICROCOMPUTER COMPONENTS AND PERIPHERALS.
DIRECT DISTANCE DIALING: A TELEPHONE EXCHANGE SERVICE WHICH ENABLES A USER TO DIAL TELEPHONE NUMBERS OUTSIDE HIS LOCAL CALLING AREA WITHOUT OPERATOR ASSISTANCE.
DISTORTION: THE MODIFICATION OF THE WAVEFORM OR SHAPE OF A SIGNAL CAUSED BY OUTSIDE INTERFERENCE OR BY IMPERFECTIONS OF THE TRANSMISSION SYSTEM. MOST FORMS OF DISTORTION ARE THE RESULT OF THE VARYING RESPONSES OF THE TRANSMISSION SYSTEM TO THE DIFFERENT FREQUENCY COMPONENTS OF THE TRANSMISSION SIGNAL.
DLC: DATA LINK CONTROL. A UNIFORM DISCIPLINE FOR THE TRANSMISSION OF DATA OVER A SINGLE COMMUNICATIONS LINK.
DLE: DATA LINK ESCAPE. THE FIRST CONTROL CHARACTER OF TWO- CHARACTER SEQUENCE USED EXCLUSIVELY TO PROVIDE SUPPLEMENTARY LINE-CONTROL SIGNALS.
DMI: DIGITAL MULTIPLEXED INTERFACE. GATEWAY PROVIDING 23 DIGITAL PCM CHANNELS + 1 SIGNALING CHANNEL AT AN AGGREGATE RATE OF 1.544M BPS. DEVELOPED BY AT&T.
DNA: DIGITAL NETWORK ARCHITECTURE. THE NETWORK ARCHITECTURE OF DIGITAL EQUIPMENT CORPORATION.
DOMSAT: DOMESTIC COMMUNICATIONS SATELLITE.
DOWNLINK: THE PORTION OF A SATELLITE CIRCUIT EXTENDING FROM THE SATILLITE TO THE EARTH.
DOWNLOAD: THE PROCESS OF LOADING SOFTWARE INTO THE NODES OF A NETWORK FROM ONE NODE OVER THE NETWORK MEDIA.
DOWNTIME: THE TOTAL TIME A SYSTEM IS OUT OF SERVICE DUE TO EQUIPMENT FAILURE.
DPNSS: A DIGITAL PRIVATE NETWORK SIGNALING SYSTEM STANDARD DEVELOPED BY BRITISH TELCOM AND OTHER UNITED KINGDOM PBX SUPPLIERS.
DS1: DIGITAL SIGNAL LEVEL 1, A DIGITAL TRANSMISSION FORMAT IN WHICH 24 VOICE CHANNELS ARE MULTIPLEXED INTO ON 1.544M BPS (US) OR 2.108M BPS (EUROPE) T1 DIGITAL CHANNEL.
DS2: DIGITAL SIGNAL LEVEL2; TELEPHONY TERM DESCRIBING THE 6.312M BPS DIGITAL SIGNAL CARRIED ON A T2 FACILITY.
DS3: DIGITAL SIGNAL LEVEL 3; TELEPHONY TERM DESCRIBING THE 44M BPS DIGITAL SIGNAL CARRIED ON A T3 FACILITY.
DS4: DIGITAL SIGNAL LEVEL 4; TELEPHONY TERM DESCRIBING THE 273M BPS DIGITAL SIGNAL CARRIED ON A T4 FACILITY.
DSA: DISTRIBUTED SYSTEMS ARCHITECTURE. THE NETWORK ARCHITECTURE DEVELOPED BY HONEYWELL.
DSN: DISTRIBUTED SYSTEM NETWORK. THE NETWORK ARCHITECTURE DEVELOPED BY HEWLETT-PACKARD.
DSO: DIGITAL SIGNAL LEVEL 0; TELEPHONY TERM FOR 64K BPS STANDARD DIGITAL TELECOMMUNICATIONS SIGNAL OR CHANNEL
DSP: DISPLAY SYSTEMS PROTOCOL. IBM PROTOCOL WHICH ALLOWS 3270 BSL CONTROL UNITS, PRINTERS, TERMINALS, ETC., TO INTERFACE WITH PDN.
DTE: DATA TERMINAL EQUIPMENT. THE EQUIPMENT COMPRISING THE DATA SOURCE, DATA SINK, OR BOTH.
EAROM: ELECTRICALLY ALTERABLE READ-ONLY MEMORY.
EARTH STATION: GROUND-BASED EQUIPMENT USED TO COMMUNICATE VIA SATELLITES.
EBCDIC: EXTENDED BINARY CODE DECIMAL INTERCHANGE CODE. AN 8-BIT (256 COMBINATIONS) CHARACTER CODE USED PRIMARILY IN IBM EQUIPMENT.
ECHO: WAVE THAT HAS BEEN REFLECTED OR OTHERWISE RETURNED WITH SUFFICIENT MAGNITUDE AND DELAY FOR IT TO BE PERCEIVED AS A WAVE DISTINCT FROM THAT DIRECTLY TRANSMITTED.
ECHOPLEX: A PROCEDURE WHEREBY THE RECEIVING STATION AUTOMATICALLY RETRANSMITS (ECHOS) EACH CHARACTER RECEIVED, SO THAT THE SENDER MAY VERIFY THE CORRECTNESS OF HIS TRANSMISSION.
EEPROM: ELECTRICALLY ERASSABLE PROGRAMMABLE READ-ONLY MEMORY. A MEMORY THAT CAN BE ELECTRONICALLY PROGRAMMED AND ERASED, BUT WHICH DOES NOT REQUIRE A POWER SOURCE TO RETAIN DATA.
EIA: ELECTRONIC INDUSTRIES ASSOCIATION. A PRIVATE U.S. STANDARDS ORGANIZATION SPECIALIZING IN THE ELECTRICAL AND FUNCTIONAL SPECIFICATION OF INTERFACE EQUIPMENT CHARACTERISTICS.
EIRP: EFFECTIVE ISOTROPIC RADIATED POWER. THE COMBINATION OF TRANSMITTED POWER AND ANTENNA GAIN.
ELECTRONIC INDUSTRIES ASSOCIATION: A PRIVATE U.S. STANDARS ORGANIZATION SPECIALIZING IN THE ELECTRICAL AND FUNCTIONAL SPECIFICATION OF INTERFACE EQUIPMENT CHARACTERISTICS.
EMI: ELECTROMAGNETIC INTERFERENCE. THE ENERGY GIVEN OFF BY ELECTRONIC CIRCUITS AND PICKED UP BY OTHER CIRCUITS; BASED ON THE TYPE OF DEVICE AND OPERATING FREQUENCY, EMI CAN BE REDUCED BY SHIELDING; MINIMUM ACCEPTABLE LEVELS ARE DETAILED BY FCC.
ENCRYPTION: THE PROCESS OF SYSTEMATICALLY ENCODING A BIT STREAM BEFORE TRANSMISSION SO THAT AN UNAUTORIZED PARTY CANNOT DECIPHER IT.
END USER: THE SOURCE AND/OR DESTINATION OF INFORMATION SENT THROUGH THE COMMUNCATIONS SYSTEM; END USERS EXIST AT ALL LEVELS.
ENQ: ENQUIRY. IN DATA COMMUNICATIONS, A REQUEST FOR A RESPONSE FROM ANOTHER TERMINAL; IT IS USED TO OBTAIN IDENTIFICATION AND/OR AN INDICATION OF THE OTHER STATION'S STATUS.
EOM: END-OF-MESSAGE.
EOT: END-OF-TAPE.
EQUALIZATION: THE INTRODUCTION OF COMPONENTS TO AN ANALOG CIRCUIT BY A MODEM TO COMPENSATE FOR SIGNAL ATTENUATION AND DELAY DISTORTION. GENERALLY, THE HIGHER THE TRANSMISSION RATE, THE GREATER THE NEED FOR EQUALIZATION.
ERGONOMICS: A DISCIPLINE THAT PROMOTES THE CONSIDERATION OF HUMAN FACTORS IN THE DESIGN OF THE WORKING ENVIORNMENT AND ITS COMPONENTS (HEAT, LIGHT, SOUND, EQUIPMENT, ETC.)
ERROR CONTROL: AN ARRANGEMENT WHICH DETECTS THE PRESENCE OF ERRORS. IN SOME SYSTEMS, ERROR CORRECTION OR RECOVER CIRCUITS ARE INCLUDED.
ESA: EUROPEAN SPACE AGENCY.
ESPRIT: EUROPEAN STRATEGIC PROGRAM FOR RESEARCH AND DEVELOPMENT IN INFORMATION TECHNOLOGIES.
ETSI: EUROPEAN TELECOMMUNICATIONS STANDARDS INSTITUTE.
EUTELSAT: EUROPEAN TELECOMMUNICATIONS SATELLITE ORGANIZATION. OPERATES THE EUTELSAT SERVICES OF SATELLITES.
EXCHANGE: ASSEMBLY OF EQUIPMENT IN A COMMUNICATIONS SYSTEM THAT CONTROLS THE CONNECTION OF INCOMING AND OUTGOING LINES AND INCLUDES THE NECESSARY SIGNALING AND SUPERVISORY FUNCTIONS. DIFFERENT EXCHANGES, OR SWITCHES, CAN BE COSITED TO PERFORM DIFFERENT FUNCTIONS. E.G., LOCAL EXCHANGE, TRUNK EXCHANGE, ETC. ALSO KNOWN AS CENTRAL OFFICE.
EXPANDOR: TRNASDUCER THAT, FOR A GIVEN AMPLITUDE RANGE OF INPUT VOLTAGES, PRODUCES A LARGER RANGE OF OUTPUT VOLTAGES.
FACSIMILE: SYSTEM FOR THE TRANSMISSION OF IMAGES, USUALLY OVER THE PUBLIC TELEPHONE NETWORK. THE IMAGE IS SCANNED AT THE TRANSMITTER, RECONSTRUCTED AT THE RECEIVING STATION, AND DUPLICATED ON SOME FORM OF PAPER.
FADING: A PHENOMENON, GENERALLY OF MICROWAVE OR RADIO TRANSMISSION, WHERE ATMOSPHERIC, ELECTROMAGNETIC, OR GRAVITATIONAL INFLUENCES CAUSE A SIGNAL TO BE DEFLECTED OR DIVERTED AWAY FROM THE TARGE RECEIVER. THE REDUCTION IN INTENSITY OF THE POWER OF A RECEIVED SIGNAL.
FAULT: A CONDITION THAT CAUSES ANY PHSICAL COMPONENT OF A SYSTEM TO FAIL TO PERFORM IN ACCEPTABLE FASHION.
FAULT TOLERANCE: THE ABILITY OF A PROGRAM OR SYSTEM TO OPERATE PROPERLY EVEN IF A FAILURE OCCURS.
FCS: CRC REMAINDER TRNASMITTED AT THE END OF A FRAME.
FDDI: FIBER DISTRIBUTED DATA INTERFACE. AN ANSI STANDARD SPECIFYING A PACKET SWITCHED LAN-TO-LAN BACKBONE FOR TRANSPORTING DATA A HIGH THROUGHPUT RATES OVER A VARITY OF MULTIMODE FIBERS.
FDM: FREQUENCY DIVISION MULTIPLEXING. DIVIDING THE AVAILABLE TRANSMISSION FREQUENCY RANGE INTO NARROWER BANDS, EACH OF WHICH IS USED FOR A SEPARATE CHANNEL.
FDM: FREQUENCY-DIVISION MULTIPLEXING. A TECHNIQUE OF DIVIDING A SINGLE COMMUNICATIONS LINE INTO SERVERAL DATA PATHS OF DIFFERENT FREQUENCIES, EACH SUPPORTING AN INDEPENDENT INFORMATION STREAM.
FDMA: FREQUENCY-DIVISION MULTIPLE ACCESS. COMMUNICATING DEVICES AT DIFFERENT LOCATIONS SHARING A MULTIPOINT OR BROADCAST CHANNEL BY MEANS OF A TECHNIQUE THAT ALLOCATES DIFFERENT FREQUENCIES TO DIFFERENT USERS.
FEEDBACK: THE RETRUN OF PART OF THE OUTPUT OF A MACHINE, PROCESS, OR SYSTEM, TO THE COMPUTER AS INPUT FROM ANOTHER PHASE; ALSO REFERS TO SYSTEM MESSAGES THAT KEEP A USER INFORMED OF SYSTEM ACTIVITIES DURING A PROCESS.
FEP: FRONT END PROCESSOR. A DEDICATED COMMUNICATIONS SYSTEM THAT INTERCEPTS AND HANDLES ACTIVITY FOR THE HOST. IT MAY PERFORM LINE CONTROL, MESSAGE HANDLING, CODE CONVERSION, ERROR CONTROL, AND SUCH APPLICATIONS FUNCTIONS AS CONTROL AND OPERATION OF SPECIAL-PURPOSE TERMINALS.
FIBER OPTICS: A TECHNOLOGY THAT USES LIGHT AS A DIGITAL INFORMATION CARRIER. FIBER OPTIC CABLES (LIGHT GUIDES) ARE A DIRECT REPLACEMENT FOR CONVENTIONAL COAXIAL CABLES AND WIRE PAIRS. THE GLASS-BASED TRANSMISSION FACILITIES OCCUPY FAR LESS PHYSICAL VOLUME FOR AN EQUIVALENT TRANSMISSION CAPACITY, WHICH IS A MAJOR ADVANTAGE IN CROWDED UNDERGROUND DUCTS. THE FIBERS ARE IMMUNE TO ELECTRICAL INTERFERENCE.
FIFO: FIRST-IN, FIRST-OUT. REFERS TO A METHOD OF COORDINATING THE SEQUENTIAL FLOW OF DATA THROUGH A BUFFER.
FILE SERVER: IN LOCAL NETWORKS, A STATION DEDICATED TO PROVIDING FILE AND MASS DATA STORAGE SERVICES TO THE OTHER STATIONS ON THE NETWORK.
FILTER: CIRCUIT DESIGNED TO TRANSMIT SIGNALS OF FREQUENCIES WITHIN ONE OR MORE FREQUENCY BANDS AND TO ATTENUATE SIGNALS OF OTHER FREQUENCIES.
FIPS 1-2: CODE FOR INFORMATION INTERCHANGE, ITS REPRESENTATIONS, SUBSETS AND EXTENSIONS.
ANSI X3.4, ANSI X3.32, ANSI X3.41 FIPS 10-3: COUNTRIES, DEPENDENCIES AND AREAS OF SPECIAL SOVEREIGNTY, AND THEIR PRINCIPAL ADMINISTRATIVE DIVISIONS.
FIPS 100-1: INTERFACE BETWEEN DATA-TERMINAL EQUIPMENT (DTE) AND DATA CIRCUIT TERMINATING EQUIPMENT (DCE) FOR OPERATION WITH PACKET-SWITCHED DATA COMMUNICATIONS NETWORKS (PSDN) OR BETWEEN TWO DTES BY DEDICATED CIRCUITS.
ANSI X3.100 CCITT X.25 FIPS 103: CODES FOR THE IDENTIFICATION OF HYDROLOGIC UNITS IN THE UNITED STATES AND THE CARIBBEAN OUTLYING AREAS.
ANSI X3.145 FIPS 104-1: AMERICAN NATIONAL STANDARD CODES FOR THE REPRESENTATION OF NAMES OF COUNTRIES, DEPENDENCIES, AND AREAS OF SPECIAL SOVEREIGNTY FOR INFORMATION INTERCHANGE.
ANSI Z39.27 ISO 3166 FIPS 107: LOCAL AREA NETWORKS: BASEBAND CARRIER SENSE MULTIPLE ACCESS WITH COLLISION DETECTDION ACCESS METHOD AND PHYSICAL LAYER SPECIFICATIONS AND LINK LAYER PROTOCOL.
ANSI/IEEE 802.2 ANSI/IEEE 802.3 FIPS 108: ALPHANUMERIC COMPUTER OUTPUT MICROFORM QUALITY TEST SLIDE.
AIIM MS28 FIPS 109: PASCAL.
ANSI/IEEE 770X3.97 FIPS 112: PASSWORD USAGE.
FIPS 113: COMPUTER DATA AUTHENTICATION.
ANSI X3.92 ANSI X9.9 FIPS 114: 200 MM (8 IN) FLEXIBLE DISK CARTRIDGE TRACK FORMAT USING TWO-FREQUENCY RECORDING AT 6631 BPRAD ON ONE SIDE-1.9 TPMM (48 TPI) FOR INFORMATION INTERCHANGE.
ISO 5654/2 FIPS 115: 200 MM (8 IN) FLEXIBLE DISK CARTRIDGE TRACK FORMAT USING MODIFIED FREQUENCY MODULATION RECORDING AT 13262 BPRAD ON TWO SIDES-1.9 TPMM (48 TPI) FOR INFORMATION INTERCHANGE.
ISO 7065/2 FIPS 116: 130 MM (5.25 IN) FLEXIBLE DISK CARTRIDGE TRACK FORMAT USING TWO-FREQUENCY RECORDING AT 3979 BPRAD ON ONE SIDE--1.9 TPMM (48 TPI) FOR INFORMATION INTERCHANGE.
ISO 6596/2 FIPS 117: 130 MM (5.25 IN) FLEXIBLE DISK CARTRIDGE TRACK FORMAT USING MODIFIED FREQUENCY MODULATION RECORDING AT 7958 BPRAD ON TWO SIDES--1.9 TPMM (48 TPI) FOR INFORMATION INTERCHANGE.
ISO 7487/3 FIPS 118: FLEXIBLE DISK CARTRIDGE LABELING AND FILE STRUCTURE FOR INFORMATION INTERCHANGE.
ISO 7665 FIPS 119: ADA.
ANSI/MIL-STD-1815A FIPS 120-1: GRAPHICAL KERNEL SYSTEM (GKS).
ANSI X3.124 ANSI X3.124.1 ANSI X3.124.2 ANSI X3.124.3 FIPS 121: VIDEOTEX/TELETEXT PRESENTATION LEVEL PROTOCOL SYSTAX (NORTH AMERICAN PLPS).
ANSI X3.110/CST500 FIPS 123: SPECIFICATION FOR A DATA DESCRIPTIVE FILE FOR INFORMATION INTERCHANGE (DDF).
ANSI/ISO 8211 FIPS 125: MUMPS.
ANSI/MDC X11.1 FIPS 126: DATABASE LANGUAGE NDL.
ANSI X3.133 FIPS 127-1: DATABASE LANGUAGE SQL.
ANSI X3.135 ANSI X3.168 FIPS 128: COMPUTER GRAPHICS METAFILE (CGM).
ANSI X3.122 FIPS 129: OPTICAL CHARACTER RECOGNITION (OCR) DOT MATRIX FOR OCR-MA CHARACTER SETS.
ANSI X3.111 FIPS 13: RECTANGULAR HOLES IN TWELVE-ROW PUNCHED CARDS.
ANSI X3.21 FIPS 133: CODING AND MODULATION REQUIREMENTS FOR 2400 BIT/SECOND MODEMS.
FIPS 134-1: CODEING AND MODULATION REQUIREMENTS FOR 4800 BIT/SECOND MODEMS.
EIA RS-449 FIPS 135: CODEING AND MODULATION REQUIREMENTS FOR DUPLEX 9600 BIT/ SECOND MODEMS.
FIPS 136: CODEING AND MODULATION REQUIREMENTS FOR DUPLEX 600 AND 1200 BIT/SECOND MDOEMS.
FIPS 137: ANALOG TO DIGITIAL CONVERSION OF VOICE BY 2400 BIT/SECOND LINEAR PREDICTIVE CODING.
FIPS 138: ELECTRICAL CHARACTERISTICS OF BALANCED VOLTAGE DIGITAL INTERFACE CIRCUITS.
EIA RS-422-A FIPS 139: INTEROPERABILITY AND SECURITY REQUIREMENTS FOR USE OF THE DATA ENCRYPTION STANDARD IN THE PHYSICAL LAYER OF DATA COMMUNICATIONS.
FIPS 14-1: HOLLERITH PUNCHED CARD CODE. ANSI X3.26
FIPS 140: GENERAL SECURITY REQUIREMENTS FOR EQUIPMENT USING THE DATA ENCRYPTION STANDARD.
FIPS 141: INTEROPERABILITY AND SECURITY REQUIREMENTS FOR USE OF THE DATA ENCRYPTION STANDARD WITH CCITT GROUP 3 FACSIMILE EQUIPMENT.
FIPS 142: ELECTRICAL CHARACTERISTICS OF UNBALANCED VOLTAGE DIGITAL INTERFACE CIRCUITS.
EIA RS-423-A FIPS 143: GENERAL PURPOSE 37-POSITION AND 9-POSITION INTERFACE BETWEEN DATA TERMINAL EQUIPMENT AND DATA CIRCUIT-TERMINATING EQUIPMENT.
EIA RS-449 FIPS 144: DATA COMMUNICATIN SYSTEMS AND SERVICES USER-ORIENTED PERFORMANCE PARAMETERS.
ANSI X3.102 FIPS 146: GOSIP: GOVERNMENT OPEN SYSTEMS INTERCONNECTION PROFILE.
FIPS 147: GROUP 3 FACSIMILE APPARATUS FOR DOCUMENT TRANSMISSION.
EIA RS-465 FIPS 148: PROCEDURES FOR DOCUMENT FACSIMILE TRANSMISSION.
EIA RS-466 FIPS 149: GENERAL ASPECTS OF GROUP 4 FACSIMILE APPARATUS.
EIA 536 FIPS 150: FACSIMILE CODING SCHEMES AND CODING CONTROL FUNCTIONS FOR GROUP 4 FACSIMILE APPARATUS.
EIA 538 FIPS 151-1: POSIX: PORTABLE OPERATING SYSTEM INTERFACE FOR COMPUTER ENVIORNMENTS.
IEEE 1003.1/POSIX FIPS 152: STANDARD GENERALIZED MARKUP LANGUAGE (SGML).
ISO 8879 FIPS 153: PROGRAMER'S HIERACHICAL GRAPHICS SYSTEM (PHIGS).
ANSI X3.144 ANSI X3.144.1 FIPS 154: HIGH SPEED 25 POSTION INTERFACE FOR DATA TERMINAL EQUIPMENT AND DATA CIRCUIT-TERMINATING EQUIPMENT.
EIA 530 FIPS 155: DATA COMMUNICATION SYSTEMS AND SERVICES USER-ORIENTED PERFORMANCE MEASUREMENT METHODS.
ANSI X3.141 FIPS 156: INFORMATION RESOURCES DICTIONARY SYSTEM (IRDS).
ANSI X3.138 FIPS 159: DETAIL SPECIFICATIONS FOR 62.5 M CODE DIAMETER/125 M CLADDING DIAMETER CLASS IA MULTIMO DE GRADED-INDEX OPTICAL WAVEGUIDE FIBERS. ANSI/EIA/TIA-492.
AAAA FIPS 16-1: BIT SEQUENCING OF CODE FOR INFORMATION INTERCHANGE IN SERIAL-BY-BIT DATA TRANSMISSION.
ANSI X3.15 FIPS 160: C (PROGRAMMING LANGUAGE).
ANSI X3.159 FIPS 17-1: CHARACTER STRUCTURE AND CHARACTER PARITY SENSE FOR SERIAL- BY-BIT DATA COMMUNICATION IN THE CODE FOR INFORMATION INTERCHANGE.
ANSI X3.16 FIPS 18-1: CHARACTER STRUCTURE AND CHARACTER PARITY SENSE FOR PARALLEL- BY-BIT DATA COMMUNICATION IN THE CODE FOR INFORMATION INTERCHANGE.
ANSI X3.25 FIPS 2-1: PERFORATED TAPE CODE FOR INFORMATION INTERCHANGE.
ANSI X3.6 FIPS 21-3: COBOL. ANSI X3.23,
ANSI X3.23A FIPS 22-1: SYNCHRONOUS SIGNALING RATES BETWEEN DATA TERMINAL AND DATA COMMUNICAITON EQUIPMENT.
ANSI X3.1 FIPS 25: RECORDED MAGNETIC TAPE FOR INFORMATION INTERCHANGE (1600 BPI, PHASE ENCODED).
ANSI X3.39 FIPS 26: ONE-INCH PERFORATED PAPER TAPE FOR INFORMATION INTERCHANGE.
ANSI X3.18 FIPS 27: TAKE-UP REELS FOR ONE-INCH PERFORATED TAPE FOR INFORMATION INTERCHANGE.
ANSI X3.20 FIPS 3-1: RECORDED MAGNETIC TAPE FOR INFORMATION INTERCHANGE (800 CPI, NRZI)
ANSI X3.22 FIPS 30: SOFTWARE SUMMARY FOR DESCRIBING COMPUTER PROGRAMS AND AUTOMATED DATA SYSTEMS.
FIPS 32-1: CHARACTER SETS FOR OPTICAL CHARACTER RECOGNITION (OCR). ANSI X3.17, ANSI X3.49,
ANSI X3.2 FIPS 33-1: CHARACTER SET FOR HANDPRINTING.
ANSI X3.45 FIPS 4-1: REPRESENTATION FOR CALENDAR DATE AND ORDINAL DATE FOR INFORMATION INTERCHANGE.
ANSI X3.30 FIPS 46-1: DATA ENCRYPTION STANDARD.
ANSI X3.92 FIPS 5-2: CODES FOR THE IDENTIFICATION OF THE STATES, THE DISTRICT OF COLUMBIA AND THE OUTLYING AREAS OF THE UNITED STATES, AND ASSOCIATED AREAS.
ANSI X3.38 FIPS 50: RECORDED MAGNETIC TAPE FOR INFORMATION INTERCHANGE (6250 CPI, (246 CPMM), GROUP CODED RECORDING).
ANSI X3.54 FIPS 51: MAGNETIC TAPE CASSETTES FOR INFORMATION INTERCHANGE (3.810 MM, (0.150 IN), TAPE AT 32 BPMM (800 BPI), PHASE ENCODED).
ANSI X3.48 FIPS 52: RECORDED MAGNETIC TAPE CARTRIDGE FOR INFORMATION INTERCHANGE, 4 TRACK, 6.30 MM (1/4 IN) 63 BPMM (1600 BPI) PHASE ENCODED.
ANSI X3.56 FIPS 53: TRANSMITTAL FORM FOR DESCRIBING COMPUTER MAGNETIC TAPE FILE PROPERTIES.
FIPS 54-1: COMPUTER OUTPUT MICROFORM (COM) FORMATS AND REDUCTION RATIOS, 16MM AND 105MM.
ANSI/AIIM MS5 ANSI/AIIM MS14 FIPS 58-1: REPRESENTATIONS OF LOCAL TIME OF THE DAY FOR INFORMATION INTERCHANGE.
ANSI X3.43 FIPS 59: REPRESENTATIONS OF UNIVERSAL TIME, LOCAL TIME DIFFERENTIALS AND UNITED STATES TIME ZONE REFERENCES FOR INFORMATION INTERCHANGE.
ANSI X3.51 FIPS 6-4: COUNTIES AND COUNTY EQUIVALENTS OF THE STATES OF THE UNITED STATES AND THE DISTRICT OF COLUMBIA.
ANSI X3.31 FIPS 66: STANDARD INDUSTRIAL CLASSIFICATION (SIC) CODES.
FIPS 68-2: BASIC.
ANSI X3.113 FIPS 69-1: FORTRAN.
ANSI X3.9 FIPS 70-1: REPRESENTATION OF GEOGRAPHIC POINT LOCATIONS FOR INFORMATION INTERCHANGE.
ANSI X3.61 FIPS 71: ADVANCED DATA COMMUNICATION CONTROL PROCEDURES (ADCCP).
ANSI X3.66 FIPS 79: MAGNETIC TAPE LABELS AND FILE STRUCTURE FOR INFORMATION INTERCHANGE.
ANSI X3.27 FIPS 8-5: METROPOLITAN STATISTICAL AREAS (MSAS) INCLUDING CMSAS, PMSAS AND NECMAS.
FIPS 81: DES MODES OF OPERATION.
ANSI X3.106 FIPS 84: MICROFILM READERS.
ANSI/AIIM (NMA) MS20 FIPS 85: OPTICAL CHARACTER RECOGNITION (OCR) INKS.
ANSI X3.86 FIPS 86: ADDITIONAL CONTROLS FOR USE WITH ASCII.
ANSI X3.64 FIPS 89: OPTICAL CHARACTER RECOGNITION (OCR) CHARACTER POSITIONING.
ANSI X3.93M FIPS 9-1: CONGRESSIONAL DIRSTICTS OF THE UNITED STATES.
FIPS 93: PARALLEL RECORDED MAGNETIC TAPE CARTRIDGE FOR INFORMATION INTERCHANGE, 4-TRACK 6.30 MM (1/4 INCH), 63 BPMM (1600 BPI), PHASE ENCODED.
ANSI X3.72 FIPS 95: CODES FOR THE IDENTIFICATION OF FEDERAL AND FEDERALLY- ASSISTED ORGANIZATIONS.
FIRMWARE: PERMANENT OR SEMIPERMANENT CONTROL CODING IMPLEMENTED AT A MICRO-INSTRUCTION LEVEL FOR AN APPLICATION PROGRAM, INSTRUCTION SET, OPERATING ROUTINE, OR SIMILAR USER-ORIENTED FUNCTION.
FLAG SEQUENCE: (HDLC,SDLC,ADCCP). THE UNIQUE SEQUENCE OF EIGHT BITS (01111110) EMPLOYED TO DELIMIT THE OPENING AND CLOSING OF A FRAME.
FLOW CONTROL: A FUNCTION FOR THE CONTROL OF THE DATA FLOW WITHIN A LAYER BETWEEN PEER ENTITIES OR BETWEEN ADJACENT LAYERS.
FLOW CONTROL: THE USE OF BUFFERING AND OTHER MECHANISMS, SUCH AS CONTROLS THAT TURN A DEVICE ON AND OFF, TO PREVENT DATA LOSS DURING TRANSMISSION.
FM: FREQUENCY MODULATION. A METHOD OF TRANSMISSION WHEREBY THE FREQUENCY OF THE CARRIER WAVE IS CHANGED TO CORRESPOND TO CHANGES IN THE BIT VALUE OF THE INFORMATION SIGNAL.
FM: FREQUENCY MODULATION. ONE OF THREE WAYS OF MODIFYING A SINE WAVE SIGNAL TO MAKE IT CARRY INFORMATION. THE SINE WARE OR "CARRIER" HAS ITS FREQUENCY MODIFIED IN ACCORDANCE WITH THE INFORMATION TO BE TRANSMITTED. THE FREQUENCY FUNCTION OF THE MODULATED WAVE MAY BE CONTINUOUS OR DISCONTINUOUS.
FOOTPRINT: 1) THE SPACE A DEVICE OCCUPIES ON A DESK OR WORK SURFACE. 2) IN SATELLITE COMMUNICATIONS, THE FOOTPRINT IS THE PRECISE AREA OF THE EARTH IN WHICH THE SIGNAL CAN BE RECEIVED. A GIVEN SATELLITE CAN HAVE A FOOTPRINT OF UP TO SEVERAL MILES IN WIDTH.
FORTRAN: FORMULA TRANSLATION. LANGUAGE USED IN PROGRAMMING COMPUTERS.
FOTS: FIBER OPTIC TRANSMISSION SYSTEMS.
FOUR-WIRE: FOUR-WIRE CIRCUIT. COMMUNICATIONS PATH IN WHICH FOUR WIRES (TWO FOR EACH DIRECTION OF TRANSMISSION) ARE CONNECTED TO THE STATION EQUIPMENT.
FOUR-WIRE CHANNEL: A CIRCUIT CONTAINING TWO PAIRS OF WIRE (OR THEIR LOGICAL EQUIVALENT) FOR SIMULTANEOUS (I.E, FULL-DUPLEX) TWO-WAY TRANSMISSION.
FOUR-WIRE CIRCUIT: A CIRCUIT IN WHICH TWO PAIRS OF CONDUCTORS, ONE FOR THE INBOUND CHANNEL AND ONE FOR THE OUTBOUND CHANNEL, ARE CONNECTED TO THE STATION EQUIPMENT.
FRAME: (HDLC,SDLC,ADCCP). THE SEQUENCE OF CONTIGUOUS BITS, BRACKETED BY AND INCLUDING OPENING AND CLOSING FLAG SEQUENCES. A VALID FRAME CONTAINS AT LEAST 32 BITS BETWEEN FLAGS AND CONTAINS AN ADDRESS FIELD, A CONTROL FIELD AND A FRAME CHECK SEQUENCE. A FRAME MAY OR MAY NO INCLUDE AN INFORMATION FIELD.
FRAME CHECK SEQUENCE: CRC REMAINDER TRANSMITTED AT THE END OF A FRAME.
FREQUENCY: AN EXPRESSION HOW FREQUENTLY A PERIODIC (REPETITIOUS) WAVE FORM OR SIGNAL REGENERATES ITSELF AT A GIVEN AMPLITUDE. IT CAN BE EXPRESSED IN HERTZ (HZ), KILOHERTZ (KHZ), MEGAHERTZ (MHZ), ETC.
FREQUENCY DIVISION MULTIPLEXING: DEVIDING THE AVAILABLE TRANSMISSION FREQUENCY RANGE INTO NARROWER BANDS, EACH OF WHICH IS USED FOR A SEPARATE CHANNEL.
FREQUENCY MODULATION: A METHOD OF TRANSMISSION WHEREBY THE FREQUENCY OF THE CARRIER WAVE IS CHANGED TO CORRESPOND TO CHANGES IN THE BIT VALUE OF THE INFORMATION SIGNAL.
FREQUENCY SHIFT KEYING: A METHOD OF FREQUENCY MODULATION IN WHICH A "1" IS REPRESENTED AS ONE FREQUENCY AND "0" AS ANOTHER FREQUENCY.
FRONT END PROCESSOR: A COMMUNICATIONS COMPUTER ASSOCIATED WITH (CHANNEL ATTACHED TO) A HOST COMPUTER.
FSK: FREQUENCY SHIFT KEYING. A METHOD OF FREQUENCY MODULATION IN WHICH A "1" IS REPRESENTED AS ONE FREQUENCY AND A "0" AS ANOTHER FREQUENCY.
FSK: FREQUENCY SHIFT KEYING. A METHOD OF MODULATION THAT USES TWO DIFFERENT FREQUENCIES TO DISINGUISH BETWEEN A MARK (DIGITAL 1) AND A SPACE (DIGITAL 0) WHEN TRANSMITTING ON AN ANALOG LINE. USER IN MODEMS OPERATING AT 1200 BPS OR SLOWER.
FTP: FILE TRANSFER PROTOCOL. A SERVICE PROVIDING A FAMILY OF COMMANDS FOR PERFORMING FILE AND DIRECTORY OPERATIONS OVER THE NETWORK, SUCH AS APPEND, RENAME AND DELETE FILES, LIST CHANGE, MAKE AND REMOVE DIRECTORIES, CHECK STATUS, TOGGLE SWITCHES, AND ASK FOR HELP.
FULL DUPLEX: SIMULTANEOUS INDEPENDENT TRANSMISSION IN BOTH DIRECTIONS.
FX: FOREIGN EXCHANGE. CONNECTS A CUSTOMER'S LOCATION TO A REMOTE EXCHANGE. THIS SERVICE PROVIDES THE EQUIVALENT OF LOCAL SERVICE FROM THE DISTANT EXCHANGE.
GATEWAY: A CONCEPTUAL OR LOGICAL NETWORK STATION THAT SERVES TO INTERCONNECT TWO OTHERWISE INCOMPATIBLE NETWORKS, NETWORK NODES, SUBNETWORKS, OR DEVICES. GATEWAYS PERFORM A PROTOCOL CONVERSION OPERATION ACROSS A WIDE SPECTRUM OF COMMUNICATIONS FUNCTIONS OR LAYERS.
GEOSYNCHRONOUS ORBIT: A COMMUNICATION SATELLITE ORBIT WHERE THE SATELLITE ROTATES IN THE SAME DIRECTION THE EARTH ROTATES, AND ITS ROTATION SPEED IS SUCH THAT THE SATELLITE APPEARS STATIONARY OVER THE SAME EARTH LOCATION. THE ORBIT IS ABOUT 22,300 MILES ABOVE THE EQUATOR TO ACHIEVE THIS DESIRED RELATIONSHIP.
GHZ: GIGAHERTZ. ONE BILLION CYCLES PER SECOND.
GIGA: ONE BILLION.
GIGAHERTZ: GHZ. A FREQUENCY UNIT EQUAL TO ONE BILLION CYCLES PER SECOND.
GOSIP: U.S. AND U.K. GOVERNMENT OSI PROCUREMENT SPECIFICATION
HALF DUPLEX: TRANSMISSION IN EITHER DIRECTION, BUT NOT BOTH DIRECTIONS SIMULTANEOUSLY.
HAND SHAKING: THE EXCHANGE OF PREDETERMINED SIGNALS FOR PURPOSES OF CONTROL WHEN A CONNECTION IS ESTABLISHED BETWEEN TWO DATA SETS.
HDLC: HIGH LEVEL DATA LINK CONTROL. ISO VERSION OF A BIT ORIENTED DATA LINK CONTROL. FUNCTIONALLY SIMILAR TO ADCCP.
HEADER: THE CONTROL INFORMATION PREFIXED IN A MESSAGE TEXT, E.G., SOURCE OR DESTINATION CODE, PRIORITY, OR MESSAGE TYPE.
HEADER: THE INITIAL PORTION OF A MESSAGE, WHICH CONTAINS ANY INFORMATION AND CONTROL CODES THAT ARE NOT PART OF THE TEST (E.G., ROUTINE, PRIORITY, MESSAGE TYPE, DESTINATION ADDRESSEE, AND TIME ORIGINATION).
HERTZ: A UNIT OF FREQUENCY EQUAL TO ONE CYCLE PER SECOND. ABBREVIATED HZ.
HERTZ: (HZ). UNIT OF ELECTROMAGNETIC FREQUENCY EQUAL TO ONE CYCLE PER SECOND.
HEURISTIC: EXPLORATORY METHODS OF PROBLEM SOLVING IN WHICH SOLUTIONS ARE ARRIVED AT BY AN INTERACTIVE, SELF-LEARNING METHOD.
HEXADECIMAL: REFERRING TO A NUMBER SYSTEM WITH 16 MEMBERS REPRESENTED BY 0 THROUGH 9 FOLLOWED BY A THROUGH F. USED TO IDENTIFY THE 16 POSSIBLE BIT PATTERNS OF HALF-BYTE; TWO HEX DIGITS REPRESENT ONE BYTE. SYNONYMOUS WITH HEX.
HF: HIGH FREQUENCY. PORTION OF THE ELECTROMAGNETIC SPECTRUM, TYPICALLY USED IN SHORT-WAVE RADIO APPLICATIONS; FREQUENCIES APPROXIMATELY IN THE DMHZ TO 30 MHZ RANGE.
HIGH LEVEL DATA LINK CONTROL: ISO VERSION OF A BIT ORIENTED DATA LINK CONTROL. FUNCTIONALLY SIMILAR TO ADCCP.
HISTOGRAM: A GRAPH OF CONTIGUOUS VERTICAL BARS REPRESENTING A FREQUENCY DISTRIBUTION IN WHICH THE GROUPS OR CLASSES OF ITEMS ARE MARKED AT EQUAL INTERVALS IN ASCENDING ORDER ON THE X AXIS, AND THE NUMBER OF ITEMS IN EACH CLASS IS INDICATED BY A HORIZONTAL LINE SEGMENT DRAWN ABOVE THE X AXIS AT A HEIGHT EQUAL TO THE NUMBER OF ITEMS IN THE CLASS.
HOST COMPUTER: A COMPUTER ATTACHED TO A NETWORK PRIMARILY PROVIDING SERVICES SUCH A COMPUTATION, DATA BASE ACCESS, SPECIAL PROGRAMS, OR PROGRAMMING LANGUAGES.
IDN: INTERGRATED DIGITAL NETWORK. NETWORK EMPLOYING BOTH DIGITAL SWITCHES AND DIGITAL TRANSMISSION.
IEEE: INSTITUTE OF ELECTRICAL AND ELECTRONICS ENGINEERS. A GROUP INVOLVED IN RECOMMENDING STANDARDS FOR THE COMPUTER AND COMMUNICATIONS FIELD.
INFRARED: PERTAINING TO THE FREQUENCY RANGE IN THE ELECTROMAGNETIC SPECTRUM THAT IS HIGHER THAN RADIO FREQUENCIES BUT BELOW THE RANGE OF VISIBLE LIGHT.
INMARSAT: INTERNATION MARITIME SATELLITE ORGANIZATION. ITS WORK NOW INCREASINGLY COVERS AERONAUTICAL AND MOBILE, AS WELL AS MARITIME, SATELLITE COMMUNICATIONS.
INTERNATIONAL STANDARDS ORGANIZATION: ANSI IN A MEMBER OF ISO. A PRIVATE INTERNATIONAL BODY WHICH RECOMMENDS STANDARDS IN A WIDE VARIETY OF FIELDS FROM PHOTOGRAPHIC FILM TO DATA COMMUNICATIONS.
INTUG: INTERNATIONAL TELECOMMUNICATIONS USERS GROUP.
IP: INTERNET PROTOCOL. PROVIDES A COMMON LAYER OVER DISIMILAR NETWORKS. IT CONTROLS COMMUNICATIONS BETWEEN TWO SPU'S RESIDING ON TWO OR MORE DIFFERENT NETWORKS.
ISO: INTERNATIONAL STANDARDS ORGANIZATION. ANSI IS A MEMBER OF ISO. A PRIVATE INTERNATIONAL BODY WHICH RECOMMENDS STANDARDS IN A WIDE VARIETY OF FIELDS FROM PHOTOGRAPHIC FILM TO DATA COMMUNICATIONS.
JACK: A DEVICE USED GENERALLY FOR TERMINATING THE PERMANENT WIRING OF A CIRCUIT, ACCESS TO WHICH IS OBTAINED BY THE INSERTION OF A PLUG.
JITTER: SLIGHT MOVEMENT OF A TRANSMISSION SIGNAL IN TIME OR PHASE THAT CAN INTRODUCE ERRORS AND LOSS OF SYNCHRONIZATION FOR HIGH-SPEED SYNCHRONOUS COMMUNICATIONS.
JUMPER: PATCH CABLE OR WIRE USED TO ESTABLISH A CIRCUIT, OFTEN TEMPORARILY, FOR TESTING OR DIAGNOSTICS.
K: THE SYMBOL FOR 2, RAISED TO THE TENTH POWER (KILO), EQUAL TO 1,024.
KILOBYTE: 1,024 BYTES.
KILOHERTZ: KHZ. ONE THOUSAND CYCLES PER SECOND.
LAN: LOCAL AREA NETWORK. A HIGH-VOLUME TRANSMISSION FACILITY INTERCONNECTING A NUMBER OF DATA DEVICES, GENERALLY WITHIN THE SAME BUILDING OR A CAMPUS.
LAP: LINK ACCESS PROTOCOL. THE UNBALANCED VERSION OF HDLC IN WHICH THE COMMUNICATIONS LINE WILL HAVE A SINGLE, PERMANENT CONTROL STATION WHICH MUST INITIATE ALL DATA TRANSFER ACTIONS.
LAPB: LINK ACCESS PROTOCOL-BALANCED. A VERSION OF HDLC IN WHICH THE COMMUNICATION LINE HAS NO SINGLE CONTROLLER, AND EITHER OF THE TWO CONNECTED STATIONS MAY INITIATE A DATA TRANSFER OPERATION.
LASER: ACRONYM FOR "LIGHT AMPLIFICATION BY STIMULATED EMISSON OF RADIATION. " LASERS CONVERT ELECTRICAL ENERGY INTO RADIANT ENERGY IN THE VISIBLE OR INFRARED PARTS OF THE SPECTRUM, EMITTING LIGHT WITH A SMALL SPECTRAL BANDWIDTH. FOR THIS REASON, THEY ARE WIDELY USED IN FIBER OPTIC COMMUNICATIONS, PARTICULARLY AS SOURCES FOR LONG-HAUL LINKS.
LAYERING: THAT ASSECT OF A NETWORK ARCHITECTURE WHICH SEPARATES FUNCTIONS INTO DISTINCT FUNCTIONAL LEVELS WHICH COMMUNICATE INDIVIDUALLY WITH LIKE LEVELS IN A DISTANT NODE.
LCD: LIQUID CRYSTAL DISPLAY. A GRAPHIC DISPLAY ON A TERMINAL SCREEN USING AN ELECTROLUMINESCENT TECHNOLOGY TO FORM SYMBOLS OR SHAPES.
LDM: LIMITED DISTANCE MODEM. A LOWER COST MODEM INTENDED FOR LIMITED DISTANCE OPERATION. ALSO CALLED SHORT HAUL MODEM.
LEASED LINE: A LINE RESERVED FOR THE EXCLUSIVE USE OF A LEASING CUSTOMER. ALSO CALLED PRIVATE LINE.
LED: LIGHT-EMITTING DIODE. SEMICONDUCTOR JUNCTION DIODE THAT EMITS RADIANT ENERGY AND IS USED AS A LIGHT SOURCE FOR FIBER OPTIC COMMUNICATIONS, PARTICULARLY FOR SHORT-HAUL LINKS. ALSO USED IN ALPHANUMERIC DISPLAYS IN ELECTRONIC TELEPHONES AND CALCULATORS.
LIMITED DISTANCE MODEM: A LOWER COST MODEM INTENDED FOR LIMITED DISTANCE OPERATION. ALSO CALLED SHORT HAUL MODEM.
LINK: THE PHYSICAL INTERCONNECTON BETWEEN TWO SYSTEMS (SOMETIMES CALLED NODES) IN A NETWORK. A LINK MAY CONSIST OF A DATA COMMUNICATIONS CIRCUIT OR A DIRECT CHANNEL (CABLE) CONNECTION.
LINK ACCESS PROTOCOL: THE UNBALANCED VERSION OF HDLC IN WHICH THE COMMUNICATIONS LINE WILL HAVE A SINGEL, PERMANENT CONTROL STATION WHICH MUST INITIATE ALL DATA TRANSFER ACTIONS.
LINK ACCESS PROTOCOL BALANCED: A VERSION OF HDLC IN WHICH THE COMMUNICATION LINE HAS NO SINGLE CONTROLLER, AND EITHER OF THE TWO CONNECTED STATIONS MAY INITIATE A DATA TRANSFER OPERATION.
LINK LAYER: THE LOGICAL ENTITY IN THE OSI MODEL CONCERNED WITH TRANSMISSION OF DATA BETWEEN ADJACENT NETWORK NODES: IT IS THE SECOND LAYER PROCESSING IN THE OSI MODEL, BETWEEN THE PHYSICAL AND THE NETWORK LAYERS.
LINK PROTOCOL: A SET OF RULES FOR DATA COMMUNICATION OVER A DATA-LINK SPECIFIED IN TERMS OF TRANSMISSION CODE, TRANSMISSION MODE, CONTROL PROCEDURES AND RECOVERY PROCEDURES.
LISP: AN INTERPRETIVE LANGUAGE DEVELOPED FOR MANIPULATION OF SYMBOLIC STRINGS AND RECURSIVE DATA; WHILE THE LANGUAGE HAS BEEN DEVELOPED TO AID IN THE HANDLING OF SYMBOLIC LISTS, IT CAN BE AND HAS BEEN USED SUCCESSFULLY IN THE MANUPULATION OF MATHEMATICAL AND ARITHMETIC LOGIC.
LOCAL AREA NETWORK: A HIGH-VOLUME DATA TRANSMISSION FACILITY INTERCONNECTING A NUMBER OF DATA DEVICES, GENERALLY WITHIN A BUILDING OR A CAMPUS.
LONGITUDINAL REDUNDANCY CHECK: A SYSTEM OF ERROR CONTROL BASED ON TRANSMISSION OF A BLOCK CHECK CHARACTER BASED ON PRESET RULES. THE CHECK CHARACTER FORMATION RULE IS APPLIED IN THE SAME MANNER TO EACH CHARACTER ON A BIT BY BIT BASIS.
LPM: LINES PER MINUTE. A REFERENCE TO PRINTER SPEEDS.
LRC: LOGITUDINAL REDUNDANCY CHECK. A SYSTEM OF ERROR CONTROL BASED ON TRANSMISSION OF A BLOCK CHECK CHARACTER BASED ON PRESET RULES. THE CHECK CHARACTER FORMATON RULE IS APPLIED IN THE SAME MANNER TO EACH CHARACTER ON A BIT BY BIT BASIS.
MAGNETIC CORE: MATERIAL USED TO STORE DATA IN MAIN MEMORY.
MAGNETIC DISK: A FLAT CIRCULAR PLATE WHERE DATA CAN BE STORED; THE INFORMATION IS ACCESSIBLE TO READING AND WRITING HEADS ON AN ARM WHICH CAN BE MOVED TO A DESIRED STORAGE AREA AS THE PLATE ROTATES.
MAGNETIC TAPE: FLEXIBLE PLASTIC MATERIAL MAGNETICALLY COATED ON ONE SIDE TO STORE INFORMATION.
MARK: PRESENCE OF A SIGNAL. IN TELEGRAPHY, MARK REPRESENTS THE CLOSED CONDITION OR CURRENT FLOWING. EQUIVALENT TO A BINARY ONE CONDITION.
MASTER CONTROL PROGRAM: A PART OF THE BURROUGHS OPERATING SYSTEM WHICH MONITORS THE HOST'S OPERATION.
MBPS: MEGABITS PER SECOND.
MCP: MASTER CONTROL PROGRAM. A PART OF THE BURROUGHS OPERATING SYSTEM WHICH MONITORS THE HOST'S OPERATION.
MEDIA: THE VEHICLES THAT STORE OR TRANSMIT INFORMATION, CLASSIFIED AS SOURCE, INPUT, AND OUTPUT.
MEDIUM: 1) THE MATERIAL ON WHICH DATA IS RECORDED; FOR EXAMPLE, MAGNETIC TYPE, DISKETTE. 2) ANY MATERIAL SUBSTANCE THAT IS, OR CAN BE, USED FOR THE PROPAGATION OF SIGNALS, USUALLY IN THE FORM OF MODULATED RADIO, LIGHT, OR ACOUSTIC WAVES, FROM ONE POINT TO ANOTHER, SUCH AS OPTICAL FIBER, CABLE, WIRE, DIELECTRIC SLAB, WATER, ARI, OR FREE SPACE.
MEGA: ONE MILLION.
MICR: MAGNETIC INK CHARACTER RECOGNITION. SPECIAL ENCODED SYMBOLS THAT CAN BE READ AND CONVERTED TO DIGITAL INFORMATION FOR A COMPUTER; GENERALLY USED ON CHECKS AND DEPOSIT SLIPS.
MICRO: ONE MILLIONTH.
MICROCOMPUTER: A SMALL-SCALE PROGRAMMABLE MACHINE THAT PROCESSES INFORMATION; IT GENERALLY HAS A SINGEL CHIP AS ITS CENTRAL PROCESSING UNIT AND INCLUDES STORAGE AND INPUT/OUTPUT FACILITIES IN THE BASIC UNIT.
MICROFICHE: A RECTANGULAR SHEET OF TRANSPARENT FILM THAT CONTAINS MULTIPLE ROWS OF GREATLY REDUCED PAGE IMAGES OF REPORT, CATALOGS, RATE BOOKS, ETC.
MICROFILM: A SMALL ROLL OF PHOTOGRAPHIC FILM WHICH CAN HOLD SEVERAL THOUSAND DOCUMENT PAGES WHICH, WHEN PROJECTED ONTO A SCREEN, PRODUCES A LEGIBLE COPY OF THE ITEM OR FORM PHOTOGRAPHED.
MICROPROCESSOR: THE CENTROL UNIT OF A MICROCOMPUTER THAT CONTAINS THE LOGICAL ELEMENTS FOR MANIPULATING AND PREFORMING ARITHMETICAL AND LOGICAL OPERATIONS ON INFORMATION.
MICROWAVE: 1) PORTION OF THE ELECTROMAGNETIC SPECTRUM ABOVE ABOUT 760 MHZ. 2) DESCRIBING HIGH-FREQUENCY TRANSMISSION SIGNALS AND EQUIPMENT THAT EMPLOY MICROWAVE FREQUENCIES, INCLUDING LINE-OF-SIGHT OPEN-AIR MICROWAVE TRANSMISSION AND, INCREASINGLY, SATELLITE COMMUNICATIONS.
MILLI: ONE-THOUSANDTH.
MINICOMPUTER: SMALL- TO MEDIUM-SCALE PROGRAMMABLE MACHINE THAT PROCESSES INFORMATION; GENERALLY THE MIDRANGE BETWEEN MICROCOMPUTERS AND MAINFRAMES, SOME CAN SUPPORT UP TO SEVERAL HUNDRED USER TERMINALS SIMULTANEOUSLY.
MNEMONIC: A SYMBOLIC NAME GIVEN TO PROGRAMS, DATA, AND INSTRUCTIONS; FOR EXAMPLE, ART FOR ARITHMETIC EXPRESSION, MPY FOR MULTIPLY, AND VNDMSTFLE FOR VENDOR MASTER FILE.
MNP: MICROCOM NETWORKING PROTOCOL. AN ERROR-CORRECTION METHOD BASED ON THE OSI REFERENCE MODEL THAT RETRANSMITS LOST OR CORRUPT DATA IN PACKETS OF INFORMATION. THE PROTOCOL WAS ORIGINALLY DEVELOPED IN 1982 BY GREGORY PEARSON OF MICROCOM AND NOW CONSISTS OF NINE SEPARATE CLASSES. MNP SUPPORTS INTERACTIVE AND FILE TRANSFER APPLICATIONS OVER DIAL-UP LINES AT TRANSFER RATES UP TO 38.4K BPS.
MODEM: (MODULATOR-DEMODULATOR) A DEVICE THAT MODULATES AND DEMODULATES SIGNALS TRANSMITTED OVER COMMUNICATIONS CIRCUITS. ALSO CALLED DATA SET.
MODEM PAIR DELAY: THE ONE WAY DELAY ADDED BY A PAIR OF MODEMS TO THE PROPAGATION DELAY ON A COMMUNICATIONS LINE.
MOS: METAL OXIDE SEMICONDUCTOR. A COMMON MATERIAL AND METHOD FOR MAKING INTERGRATED CIRCUITS.
MOTHERBOARD: THE CENTRAL CARD OF A COMPUTER; IT FEATURES FEMALE CONNECTORS THAT ACCEPT OTHER PRINTED CIRCUIT CARDS.
MOUSE: A HANDHELD DEVICE, SEPARATE FROM A KEYBOARD, USED TO CONTROL THE POSITION INDICATOR ON A DISPLAY SCREEN; AS THE DEVICE IS ROLLED ALONG A TABLETOP, ITS RELATIVE POSITION APPROXIMATES THE POSITION OF THE INDICATOR.
MS-DOS: MICROSOFT DISK OPERATING SYSTEM; A MASTER CONTROL PROGRAM FOR 16 BIT SYSTEM.
MTBF: MEAN-TIME-BETWEEN-FAILURE. AVERAGE LENGTH OF TIME FOR WHICH THE SYSTEM, OR COMPONENT OF THE SYSTEM, WORKS WITHOUT FAULT.
MTTR: MEAN-TIME-TO-REPAIR. THE AVERAGE TIME REQUIRED TO PERFORM CORRECTIVE MAINTENANCE ON A FAILED DEVICE.
MULTIACCESS: THE ABILITY FOR SEVERAL USERS TO COMMUNICATE WITH A COMPUTER AT THE SAME TIME.
MULTIBUS: INTEL'S CENTRAL PATH (CHANNEL) FOR TRANSMITTING ELECTRICAL SIGNALS AND DATA; IT WAS DEVELOPED FOR USE IN 8- AND 16-BIT COMPUTER SYSTEMS.
MULTILEAVING: THE TRANSMISSION OF A VARIABLE NUMBER OF DATASTREAMS BETWEEN USER DEVICES AND A COMPUTER, USUALLY VA BISYNC FACILITIES AND USING BISYNC PROTOCOLS.
MULTIPLEXER: MUX. A DEVICE THAT ENABLES MORE THAN ONE SIGNAL TO BE SENT SIMULTANEOUSLY OVER ONE PHYSICAL CHANNEL. IT COMBINES INPUTS FROM TWO OR MORE TERMINALS, COMPUTER PORTS, OR OTHER MULTIPLEXERS, AND TRANSMITS THE COMBINED DATASTREAM OVER A SINGLE HIGH-SPEED CHANNEL. AT THE RECEIVING END, THE HIGH-SPEED CHANNEL IS DEMULTIPLEXED, EITHER BY ANOTHER MULTIPLEXER OR BY SOFTWARE.
MULTIPLEXING: A DIVISION OF A TRANSMISSION FACILITY INTO TWO OR MORE CHANNELS. SEE: FREQUENCY DIVISION MULTIPLEXING AND TIME DIVISION MULTIPLEXING.
MULTIPLEXING: DIVISION OF A TRANSMISSION FACILITY INTO TWO OR MORE CHANNELS EITHER BY SPLITTING THE FREQUENCY BAND TRANSMITTED BY THE CHANNEL INTO NARROWER BANDS, EACH OF WHICH IS USED TO CONSTITUTE A DISTINCT CHANNEL (FREQUENCY-DIVISION MULTIPLEX), OR BY ALLOTTING THIS COMMON CHANNEL TO SEVERAL DIFFERENT INFORMATION CHANNELS, ONE AT A TIME (TIME-DIVISION MULTIPLEXING).
MULTIPOINT: PERTAINING OR REFERRING TO A COMMUNICATIONS LINE TO WHICH THREE OR MORE STATIONS ARE CONNECTED. IT IMPLIES THAT THE LINE PHYSICALLY EXTENDS FROM ONE STATION TO ANOTHER UNTIL ALL ARE CONNECTED.
MULTIPOINT LINE: A SINGLE COMMUNCATIONS LINE TO WHICH MORE THAN ONE TERMINAL IS ATTACHED. ALSO CALLED MULTI-DROP.
MULTIPROCESSING: SIMULTANEOUS APPLICATION OF MORE THAN ONE PROCESSOR IN A MULTI-CPU COMPUTER SYSTEM TO THE EXECUTION OF A SINGLE USER JOB, WHICH IS POSSIBLE ONLY IF THE JOB CAN BE EFFECTIVELY DEFINED IN TERMS OF A NUMBER OF INDEPENDENTLY EXECUTABLE COMPONENTS.
MULTIPROCESSOR: A COMPUTER SYSTEM WITH TWO OR MORE CENTRAL COMPUTERS UNDER COMMON CONTROL.
MULTIPROGRAMMING: A TECHNIQUE ALLOWING SEVERAL PROGRAMS TO RUN ON ONE COMPUTER SYSTEM AT THE SAME TIME.
MULTITASKING: TWO OR MORE PROGRAM SEGMENTS RUNNING IN A COMPUTER AT THE SAME TIME.
MULTITHREADING: CONCURRENT PROCESSING OF MORE THAN ONE MESSARE (OR SIMILAR SERVICE REQUEST) BY AN APPLICATION PROGRAM.
MULTIUSER: A COMPUTER THAT CAN SUPPORT SEVERAL WORKSTATION OPERATING SIMULTANEOUSLY.
NAK: NEGATIVE ACKNOWLEDGMENT. AN INDICATION THAT A PREVIOUS TRANSMISSION WAS IN ERROR AND THE RECEIVER IS READY TO ACCEPT RETRANSMISSION.
NANO: ONE-BILLIONTH.
NANOMETER: ONE-BILLIONTH OF A METER.
NANOSECOND: ONE-BILLIONTH OF A SECOND.
NARUC: NATIONAL ASSOCIATION OF REGULATORY UTILITY COMMISSIONERS.
NATA: NORTH AMERICAN TELECOMMUNICATIONS ASSOCIATION.
NCCF: NETWORK COMMUNICATIONS CONTROL FACILITY (IBM,SNA). ALONG WITH NPDA THIS PROGRAM PRODUCT ALLOWS FOR THE MONITORING OF A COMPLETE SNA NETWORK FROM A CENTRAL LOCATION.
NCP: NETWORK CONTROL PROGRAM (IBM,SNA). THE PROGRAM WHICH RESIDES IN THE COMMUNICATIONS CONTROLLER PERFORMING ALL ROUTING, LINE CONTROL, AND BUFFERING FUNCTIONS FOR THE COMMUNICATION LINES FOR WHICH IT IS RESPONSIBLE.
NEPER: BASIC UNIT OF A LOGARITHMIC SCAL USED FOR THE EXPRESSION OF RATIOS OF VOLTAGES, CURRENTS, AND SIMILAR QUANTITIES.
NETIPC: NETWORK INTERPROCESS COMMUNICATIONS. PERMITS INTER-CPU PROGRAM SHARING AND ALLOWS PROGRAMS RUNNING ON DIFFERENT SYSTEMS TO EXCHANGE DATA THROUGH A SET OF PROGRAMMATIC CALLS. THIS PEER-TO-PEER SERVICE IS IMPORTANT FOR DEVELOPING DISTRIBUTED APPLICATIONS.
NETWORK LAYER: IN THE OSI MODEL, THE LOGICAL NETWORK ENITY THAT SERVICES THE TRANSPORT LAYER. IT IS RESPONSIBLE FOR ENSURING THAT DATA PASSED TO IT FROM THE TRANSPORT LAYER IS ROUTED AND DELIVERED THROUGH THE NETWORK.
NFS: NETWORK FILE SYSTEM. AN INDUSTRY STANDARD FOR REMOTE FILE ACCESS ACROSS A COMMON NETWORK; IT ALLOWS WORKSTATIONS TO SHARE FILE SYSTEMS IN A MULTIVENDOR NETWORK OF MACHINES AND OPERATING SYSTEMS. INCLUDES RFS, RPC, XDR, AND YP.
NFT: NETWORK FILE TRANSFER. COPIES FILES BETWEEN ANY TWO NODES ON A NETWORK, EITHER INTERACTIVELY OR PROGRAMMATICALLY. ALLOWS USER TO 1) COPY REMOTE FILE, 2) TRANSLATE FILE ATTRIBUTES, AND 3) ACCESS REMOTE ACCOUNTS.
NPDA: NETWORK PROBLEM DETERMINATION APPLICATION. A PROGRAM PRODUCT WHICH ALONG WITH NCCP ALLOWS FOR THE MONITORING OF AN ENTIRE NETWORK FROM A SINGEL LOCATION, COLLECTION OF STATISTICS, AND ISOLATION OF COMMUNICATION FAULTS.
OCR: OPTICAL CHARACTER RECOGNITION. A LIGHT-SENSITIVE SCANNING PROCESS WHERE A DEVICE PRECEIVES ACTUAL CHARACTER IMAGES AND CONVERTS THEM INTO DIGITAL CODE.
OPTICAL DISKS: STORAGE DEVICES THAT USE LASER TECHNOLOGY TO RECORD DATA; THEY FEATURE GREATER STORAGE CAPACITY THAN MAGNETIC DISKS BUT DO NOT ALLOW DATA TO BE OVER-WRITTEN.
OSI: OPEN SYSTEMS INTERCONNECTION. REFERRING TO THE REFERENCE MODEL, OSI IS A LOGICAL STRUCTURE FOR NETWORK OPERATIONS STANDARDIZED WITHIN THE OSI; A SEVEN-LAYER NETWORK ARCHITECTURE BEING USED FOR THE DEFINITION OF NETWORK PROTOCOL STANDARDS TO ENABLE ANY OSI-COMPATIBLE COMPUTER OR DEVICE TO COMMUNICATE WITH ANY OTHER OSI-COMPLIANT COMPUTER OR DEVICE FOR A MEANINGFUL EXCHANGE OF INFORMATION.
PABX: PRIVATE AUTOMATIC BRANCH EXCHANGE.
PACKET: A GROUP OF BITS INCLUDING DATA AND CONTROL ELEMENTS WHICH IS SWITCHED AND TRANSMITTED AS A COMPOSITE WHOLE. IMPLEMENTED IN CCITT X.25 PROTOCOL.
PACKET SWITCHED NETWORK: A NETWORK DESIGNED TO CARRY DATA IN THE FORM OF PACKETS. THE PACKET AND ITS FORMAT IS INTERNAL TO THAT NETWORK. THE EXTERNAL INTERFACES MAY HANDLE DATA IN DIFFERENT FORMATS, AND CONVERSION IS DONE BY AN INTERFACE COMPUTER.
PACKET SWITCHING: A DATA TRANSMISSION PROCESS, UTILIZING ADDRESSED PACKETS, WHEREBY A CHANNEL IS OCCUPIED ONLY FOR THE DURATION OF TRANSMISSION OF THE PACKET.
PAD: PACKET ASSEMBLE/DISASSEMBLER. A PROTOCOL CONVERSION DEVICE OR PROGRAM THAT PERMITS END-USER DEVICES (E.G., TERMINALS) TO ACCESS A PACKET SWITCHED NETWORK.
PAM: PULSE AMPLITUDE MODULATION. FORM OF MODULATION IN WHICH THE AMPLITUDE OF THE PULSE CARRIER IS VARIED IN ACCORDANCE WITH SUCCESSIVE SAMPLES OF THE MODULATING SIGNAL.
PARALLEL TRANSMISSION: METHOD OF DATA TRANSFER IN WHICH ALL BITS OF A CHARACTER OR BYTE ARE TRANSMITTED SIMULTANEOUSLY.
PARITY: A CONSTANT STATE OR EQUAL VALUE. PARITY CHECKING IS ONE OF THE OLDEST ERROR CHECKING TECHNIQUES. CHARACTER BIT PATTERNS ARE FORCED INTO PARITY (TOTAL NUMBER OF ONE BITS, ODD OR EVEN) BY ADDING ONE OR ZERO BIT, AS APPROPRIATE, AS THEY ARE TRANSMITTED; THE PARITY (ODD OR EVEN) IS THEN VERIFIED UPON RECEIPT BY THE RECEIVING DEVICE.
PARITY BIT: A CHECK BIT APPENDED TO AN ARRAY OF BINARY DIGITS TO MAKE THE SUM OF ALL THE BINARY DIGITS, INCLUDING THE CHECK BIT, ALWAYS ODD OR ALWAYS EVEN.
PARITY CHECK: ADDITON OF NON-INFORMATION BITS TO DATA, MAKING THE NUMBER OF ONES IN EACH GROUPING OF BITS EITHER ALWAYS ODD FOR ODD PARITY OR ALWAYS EVEN FOR EVEN PARITY. USED FOR ERROR DETECTION PURPOSES.
PBX: PRIVATE BRANCH EXCHANGE. A TELEPHONE SWITCH LOCATED ON A CUSTOMER'S PREMISES THAT PRIMARILY ESTABLISHES VOICE-GRADE CIRCUITS, OVER TIE-LINES BETWEEN INDIVIDUAL USERS AND THE SWITCHED TELEPHONE NETWORK. TYPICALLY, THE PBX ALSO PROVIDES SWITCHING WITHIN A CUSTOMER PREMISES' LOCAL AREA AND USUALLY OFFERS NUMBEROUS OTHER ENHANCED FEATURES, SUCH AS LEAST-COST ROUTING AND CALL-DETAIL RECORDING.
PDN: PUBLIC DATA NETWORK. A NETWORK DESIGNED PRIMARILY FOR DATA TRANSMISSION AND INTENDED FOR SHARING BY MANY USERS FROM MANY ORGANIZATIONS.
PHASE MODULATION: A METHOD OF TRANSMISSION WHEREBY THE ANGLE OF PHASE OF THE CARRIER WAVE IS VARIED IN ACCORDANCE WITH THE SIGNAL.
PM: PHASE MODULATION. A METHOD OF TRANSMISSION WHEREBY THE ANGLE OF PHASE OF THE CARRIER WAVE IS VARIED IN ACCORDANCE WITH THE SIGNAL.
POINT TO POINT: A NETWORK CONFIGURATION IN WHICH A CONNECTION IS ESTABLISHED BETWEEN TWO, AND ONLY TWO, TERMINAL INSTALLATIONS. AS OPPOSED TO MULTIPOINT.
POLLING: THE PROCESS OF INVITING ANOTHER STATION OR NODE TO TRANSMITT DATA.
POLLING: A METHOD OF CONTROLLING THE SEQUENCE OF TRANSMISSION BY TERMINALS ON A MULTIPOINT LINE BY REQUIRING EACH TERMINAL TO WAIT UNTIL THE CONTROLLING PROCESSOR REQUESTS IT TO TRANSMIT.
PRESENTATION LAYER: IN THE OSI MODEL, THAT LAYER OF PROCESSING THAT PROVIDES SERVICES TO THE APPLICATION LAYER, ALLOWING IT TO INTERPRET THE DATA EXCHANGED, AS WELL AS TO STRUCTURE DATA MESSAGES TO BE TRANSMITTED IN A SPECIFIC DISPLAY AND CONTROL FORMAT.
PRIVATE LINE: SEE LEASED LINE.
PROCESS: PERFORMING OPERATIONS ON INFORMATION.
PROCESSOR: A COMPUTER CAPABLE OF RECEIVING INFORMATION, MANIPULATING IT, AND SUPPLYING RESULTS.
PROGAGATION DELAY: THE ONE WAY DELAY INTRODUCED BY THE TIME IT TAKES AN ELECTRICAL IMPULSE TO TRAVEL ALONG A PHYSICAL TRANSMISSION LINE OR THROUGH SPACE.
PROGRAM: A GROUP OF INSTRUCTIONS THAT DIRECT A COMPUTER'S TASKS.
PROGRAMMER: A PERSON WHO DESIGNS, WRITES, AND TESTS COMPUTER PROGRAMS.
PROM: PROGRAMMABLE READ-ONLY MEMORY. AN INFORMATION STORATE AREA THAT CAN BE RECORDED BY AN OPERATOR; INFORMATION STORED THERE CAN ONLY BE ALTERED THROUGH SPECIAL PHYSICAL PROCESSES.
PROMPTING: MESSAGES FROM A COMPUTER THAT GIVE INSTRUCTIONS TO THE USER.
PROTOCOL: A FORMAL SET OF CONVENTIONS OR RULES GOVERNING THE FORMAT, TIMING, AND ERROR CONTROL TO FACILITATE MESSAGE EXCHANGE BETWEEN TWO COMMUNICATING PROCESSES.
PROTOCOL CONVERSION: THE PROCESS OF TRANSLATING THE PROTOCOL NATIVE TO AN END-USER DEVICE (E.G, A TERMINAL) INTO A DIFFERENT PROTOCOL (E.G., ASCII TO BSC), ALLOWING THAT END-USER DEVICE TO COMMUNICATE WITH ANOTHER DEVICE (E.G., A COMPUTER) WITH WHICH IT WOULD OTHERWISE BE INCOMPATIBLE. PROTOCOL CONVERSION CAN BE PERFORMED BY A DECICATED DEVICE, BY A SOFTWARE PACKAGE LOADED ONTO AN EXISTING SYSTEM, SUCH AS A GENERAL-PURPOSE COMPUTER, FRONT-END PROCESSOR, OR PBX SYSTEM
PSTN: PUBLIC SWITCHED TELEPHONE NETWORK. THE COMPLETE PUBLIC TELEPHONE SYSTEM, INCLUDING TELEPHONES, LOCAL AND TRUNK LINES, AND EXCHANGES.
PUBLIC DATA NETWORK: A NETWORK DESIGNED PRIMARILY FOR DATA TRANSMISSION AND INTENDED FOR SHARING BY MANY USERS FROM MANY ORGANIZATIONS.
PULSE CODE MODULATON: DIGITAL MODULATION IN WHICH THE MESSAGE IS REPRESENTED BY A CODED GROUP. A TYPE OF A/D CONVERSION.
RAM: RANDOM-ACCESS MEMORY. A STORAGE TECHNIQUE IN WHICH THE TIME REQUIRED TO OBTAIN DATA IS INDEPENDENT OF THE LOCATION.
REDUNDANCY: 1) PORTION OF THE TOTAL INFORMATION CONTAINED IN A MESSAGE THAT CAN BE ELIMINATED WITHOUT LOSS OF ESSENTIAL INFORMATION. 2) PROVISION OF DUPLICATE, BACKUP EQUIPMENT TO IMMEDIATELY TAKE OVER THE FUNCTION OF EQUIPMENT THAT FAILS. 3) IN A DATABASE, THE STORAGE OF THE SAME DATA ITEM OR GROUP OF ITEMS IS TWO OR MORE FILES.
RESPONSE TIME: THE AMOUNT OF TIME ELAPSED BETWEEN A GENERATION OF AN INQUIRY AT A TERMINAL AND RECEIPT OF A RESPONSE AT THAT SAME TERMINAL.
RF: RADIO FREQUENCY. A FREQUENCY THAT IS HIGHER THAN THE AUDIO FREQUENCIES BUT BELOW THE INFRARED FREQUENCIES, USUALLY ABOVE 20KHZ.
RFI: RADION FREQUENCY INTERFERENCE. SIGNAL INTERFERENCE GENERATED AT OR NEAR A RECEIVED WAVELENGTH. THE FCC ESTABLISHES RFI STANDARDS TO REDUCE RFI.
RFI: REQUEST FOR INFORMATION. GENERAL NOTIFICATION OF AN INTENDED PURCHASE OF COMMUNICATIONS OR COMPUTER EQUIPMENT SENT TO POTENTIAL SUPPLIERS TO DETERMINE INTEREST AND SOLICIT PRODUCT MATERIALS.
RFP: REQUEST FOR PROPOSAL. FOLLOW-UP TO RFI, SENT TO INTERESTED VENDORS TO SOLICIT A CONFIGURATION PROPOSAL, WITH PRICES, THAT MEETS A USER'S REQUIREMENTS.
RGB: RED, GREEN, BLUE MONITOR. A COLOR DISPLAY SCREEN FOR COMPUTERS.
ROM: READ-ONLY MEMORY. HIGH SPEED INTERNAL MEMORY CONTAINING PERMANENTLY RECORDED INFORMATION.
RS232: A LEVEL 1 STANDARD PROMULGATED BY EIA FOR THE PHYSICAL INTERFACE BETWEEN DATA COMMUNICATIONS EQUIPMENT (DCE) AND DATA TERMINAL EQUIPMENT (DTE)
RS422: A LEVEL 1 STANDARD PROMULGATED BY EIA FOR THE PHSICAL INTERFACE BETWEEN DATA COMMUNICATIONS EQUIPMENT (DCE) AND DATA TERMINAL EQUIPMENT (DTE).
RS449: A LEVEL 1 STANDARD PROMULGATED BY EIA FOR THE PHYSICAL INTERFACE BETWEEN DATA COMMUNICATIONS EQUIPMENT (DCE) AND DATA TERMINAL EQUIPMENT (DTE). EIA SPECIFICATION FOR GENERAL PURPOSE, 37-POSITION AND 9-POSITION INTERFACE FOR DTE AND DCE EMPLOYING SERIAL BINARY DATA INTERCHANGE.
SAA: SYSTEMS APPLICATION ARCHITECTURE. IBM'S ANNOUNCED FRAMEWORK FOR ALLOWING DEVELOPMENT OF CONSISTENT APPLICATIONS ACROSS SIX SOFTWARE ENVIRONMENTS (TSO/F, CICS/MVS, IMS/ESA/TM, VM/CMS, OS400, AND OS/2 EXTENDED EDITION) RUNNING ON THREE HARDWARE COMPUTING PLATFORMS (SYSTEMS 370 ESA, OS/400, AND PS/2).
SDLC: IBM'S VERSION OF A BIT ORIENTED DATA LINK CONTROL PROTOCOL.
SELECTING: IN THE BSC POLLED PROTOCOL, THE PROCESS OF INFORMING A PARTICULAR STATION THAT THE NEXT TRANSMISSION IS DIRECTED TO THAT STATION.
SEMICONDUCTOR: A SUBSTANCE THAT CAN ACT AS A CONDUCTOR OR INSULATOR OF ELECTRICITY DEPENDING ON ITS CHARGED STATE; IT ACTS AS AN ON/OFF SWITCH SIGNIFYING BINARY DIGITS (1'S AND O'S).
SERIAL: SERIAL TRANSMISSION. A METHOD OF TRANSMISSION IN WHICH EACH BIT OF INFORMATION IS SENT SEQUENTIALLY ON A SINGEL CHANNEL RATHER THAN SIMULTANEOUSLY AS IN PARALLEL TRANSMISSION.
SERVER: A PROCESSOR THAT PROVIDES A SPECIFIC SERVICE TO THE NETWORK, E.G., A ROUTING SERVER CONNECTS NODES AND NETWORK OF LIKE ARCHITECTURES, A GATEWAY SERVER CONNECTS NODES AND NETWORKS OF DIFFERENT ARCHITECTURES, ETC.
SHIELD PAIR: TWO INSULATED WIRES IN A CABLE WRAPPED WITH METALLIC BRAID OR FOIL TO PREVENT INTERFERENCE AND PROVIDE NOISE-FREE TRANSMISSION.
SIMPLEX: SIMPLEX MODE. OPERATION OF A CHANNEL IN ONE DIRECTION ONLY WITH NO CAPABILITY OF REVERSING.
SIX BIT TRANSCODE: A SIX BIT CHARACTER CODE USERD PRIMARILY BY IBM EQUIPMENT.
SMS: SHORT MESSAGE SERVICE DEFINED BY GSM FOR WIRELESS.
SMTP: SIMPLE MAIL TRANSFER PROTOCOL. SERVICE SPECIFICALLY FOR ELECTRONIC MAIL THAT FUNCTIONS AS A UNIFIED "POST OFFICE" FOR ADDRESSING MAIL TO ALL USERS ON ALL NODES OF BOTH WIDE AREA AND LOCAL NETWORKS.
SNA: SYSTEMS NETWORK ARCHITECTURE. IBM'S LAYERED TRANSMISSION PROTOCOL FOR DATA COMMUNICATIONS AMONG IBM COMPUTERS AND TERMINALS.
SNA: SYSTEMS NETWORK ARCHITECTURE. THE COMPUTER AND COMMUNICATIONS NETWORK ARCHITECTURE DEFINED BY IBM. THE TOTAL DESCRIPTION OF THE LOGICAL STRUCTURE, FORMATS, PROTOCOLS, AND OPERATIONS SEQUENCES FOR TRANSMITTING INFORMATION UNITS THROUGH THE COMMUNICATION SYSTEM.
SNA: SYSTEMS NETWORK ARCHITECTURE. IBM'S STANDARDIZED RELATIONSHIP BETWEEN ITS VIRTUAL TELECOMMUNICATION ACCESS METHOD (VTAM) AND THE NETWORK CONTROL PROGRAM (NCP/VS).
SOH: START OF HEADER. A COMMUNICATION CONTROL CHARACTER USED TO IDENTIFY THE BEGINNING OF THE HEADER FIELD OF A MESSAGE BLOCK.
SOP: STANDARD OPERATING PROCEDURE.
SPACE: USUALLY EQUIVALENT TO A BINARY ZERO CONDITION.
SSCP: SYSTEM SERVICES CONTOL POINT. THE ADDRESSABLE UNIT IN AN SNA DOMAIN WHICH IS RESPONSIBLE FOR OVERALL CONTROL OF THE RESOURCES IN THAT DOMAIN.
STAR: A NETWORK TOPOLOGY IN WHICH EACH STATION IS CONNECTED ONLY TO A CENTRAL STATION BY A POINT-TO-POINT LINK AND COMMUNICATES WITH ALL OTHER STATIONS THROUGH THE CENTRAL STATION.
STARLAN: A LOCAL NETWORK DESIGN AND SPECIFICATION WITHIN IEEE 802.3 STANDARDS SUBCOMMITTEE, CHARACTERIZED BY 1M BPS BASEBAND DATA TRANSMISSION OVER TWO-PAIR, TWISTED-PAIR WIRING.
START BIT: IN ASYNCHRONOUS TRANSMISSION, THE BIT WHICH SYNCHRONIZES THE RECEIVER CLOCK TO THE RECEIVING DATA, DONE AT EACH RECEIVED CHARACTER. THE START BIT IS ALWAYS A SPACE.
START OF HEADER: A COMMUNICATION CONTROL CHARACTER USED TO IDENTIFY THE BEGINNING OF THE HEADER FIELD OF A MESSAGE BLOCK.
START OF TEXT: A COMMUNICATION CONTROL CHARACTER WHICH PRECEDES THE TEXT IN THE MESSAGE BLOCK.
STATION: THE DATA TERMINAL EQUIPMENT FROM OR TO WHICH MESSAGES ARE TRANSMITTED ON A DATA LINK.
STATISTICAL MULTIPLEXING: A SYSTEM OF TIME DIVISION MULTIPLEXING ON WHICH ONLY THE LIVE DATA ON EACH LOW SPEED CHANNEL IS ALLOCATED TO TIME SLOTS ON THE HIGH SPEED CHANNEL BETWEEN MULTIPLEXERS.
STATMUX: STATISTICAL MULTIPLEXING. A SYSTEM OF TIME DIVISION MULTIPLEXING ON WHICH ONLY THE LIVE DATA ON EACH LOW SPEED CHANNEL IS ALLOCATED TO TIME SLOTS ON THE HIGH SPEED CHANNEL BETWEEN MULTIPLEXERS.
STOP BIT: IN ASYCHRONOUS TRANSMISSION THE BIT/S WHICH TERMINATE THE CHARACTER FRAME, ALWAYS A MARK, SO THAT A START BIT WILL BE CLEARLY RECOGNIZED ON THE MARK-TO-SPACE TRANSITION.
STORE AND FORWARD: THE PROCESS OF MESSAGE HANDLING USED IN MESSAGE SWITCHING SYSTEMS IN WHICH MESSAGES ARE TEMPORARILY STORED AND THEN FORWARDED.
STX: START OF TEXT. A COMMUNICATION CONTROL CHARACTER WHICH PRECEDES THE TEXT IN THE MESSAGE BLOCK.
SUPERSCRIPT: A SYMBOL THAT APPEARS ABOVE THE CHARACTER BASE LINE.
SWITCHED LINE: A COMMUNICATION LINK FOR WHICH THE PHYSICAL PATH MAY VARY WITH EACH USAGE, E.G., THE DIAL-UP TELEPHONE NETWORK.
SYNCHRONOUS: SYNCHRONOUS TRANSMISSION. TRANSMISSION IN WHICH THE DATA CHARACTERS AND BITS ARE TRANSMITTED AT A FIXED RATE WITH THE TRANSMITTER AND RECEIVER SYNCHRONIZED.
SYNCHRONOUS DATA LINK CONTROL: IBM'S VERSION OF A BIT ORIENTED DATA LINK CONTROL PROTOCOL.
SYSGEN: SYSTEM GENERATION. THE PROCESS OF USING A MASTER CONTROL PROGRAM TO ASSEMBLE AND LINK ALL THE PARTS THAT CONSTITUTE ANOTHER OPERATING SYSTEM.
SYSTEMS NETWORK ARCHITECTURE: IBM'S LAYERED TRANSMISSION PROTOCOL FOR DATA COMMUNICATIONS AMONG IBM COMPUTERS AND TERMINALS.
SYSTEMS NETWORK ARCHITECTURE: THE COMMPUTER AND COMMUNICATIONS NETWORK ARCHITECTURE DEFINED BY IBM. THE DTOAL DESCRIPTION OF THE LOGICAL STRUCTURE, FORMATS, PROTOCOLS, AND OPERATIONAL SEQUENCES FOR TRANSMITTING INFORMATION UNITS THROUGH THE COMMUNICATION SYSTEM.
T1: A DIGITAL CARRIER FACILITY USED TO TRANSMIT A DS1 FORMATED DIGITAL SIGNAL AT 1.544M BPS; THE EQUIVALENT OF 24 VOICE CHANNELS. THE EUROPEAN EQUIVALENT TRANSMITS A 2.048M BPS.
T1C: A DIGITAL CARRIER FACILITY USED TO TRANSMIT A DS1C FORMATTED DIGITAL SIGNAL AT 3.153M BPS; THE EQUIVALENT OF 48 VOICE CHANNELS.
T2: A DIGITAL CARRIER FACILITY USED TO TRANSMIT A DS2 FORMATED DIGITAL CARRIER SIGNAL AT 6.312M BPS; THE EQUIVALENT OF 94 VOICE CHANNELS.
T3: A DIGITAL CARRIER FACILITY USED TO TRANSMIT A DS3 FORMATTED DIGITAL SIGNAL AT 44M BPS; THE EQUIVALENT OF 672 VOICE CHANNELS.
T4: A DIGITAL CARRIER FACILITY USED TO TRANSMIT A DS4 FORMATTED DIGITAL CARRIER SIGNAL AT 273M BPS; THE EQUIVALENT OF 4,032 VOICE CHANNELS.
TCAM: TELECOMMUNICATIONS ACCESS METHOD. AN IBM MACRO LANGUAGE FOR CREATING COMMUNICATION APPLICATIONS PROGRAMS AND MESSAGE CONTROL.
TCP/IP: TRANSMISSION CONTROL PROTOCOL/INTERNET PROTOCOL. ENSURES PACKETS OF DATA ARE DELIVERED TO THEIR DESTINATIONS IN THE SEQUENCE IN WHICH THEY WERE TRANSMITTED.
TDM: TIME DIVISION MULTIPLEXING. A SYSTEM OF MULTIPLEXING IN WHICH CHANNELS ARE ESTABLISHED BY CONNECTING TERMINALS ONE AT A TIME AT REGULAR INTERVALS BY MEANS OF AN AUTOMATIC DISTRIBUTION.
TELNET: TELETYPE NETWORK. PROVIDES A VIRTUAL TERMINAL CAPABILITY FOR ACCESSING REMOTE SYSTEMS AS A TERMINAL.
TEXT: A SEQUENCE OF CHARACTERS FORMING PART OF A TRANSMISSION WHICH IS SENT FROM THE DATA SOURCE TO THE DATA SINK, AND CONTAINS THE INFORMATIO TO BE CONVEYED.
TIME DIVISION MULTIPLEXING: A SYSTEM OF MULTIPLEXING IN WHICH CHANNELS ARE ESTABLISHED BY CONNECTING TERMINALS ONE AT A TIME AT REGULAR INTERVALS BY MEANS OF AN AUTOMATIC DISTRIBUTION.
TOKEN BUS: A LOCAL NETWORK ACCESS MECHANISM AND TOPOLOGY IN WHICH ALL STATIONS ACTIVELY ATTACHED TO THE BUS LISTEN FOR A BROADCAST TOKEN OR SUPERVISORY FRAME. STATIONS WISHING TO TRANSMIT MUST RECEIVE THE TOKEN BEFORE DOING SO; HOWEVER, THE NEXT PHYSICAL STATION TO TRANSMIT IS NOT NECESSARILY THE NEXT PHYSICAL STATION ON THE BUS. BUS ACCESS IS CONTROLLED BY PREASSIGNED PRIORITY ALGORITHMS.
TOKEN PASSING: A LOCAL AREA NETWORK ACCESS TECHNIQUE IN WHICH PARTICIPATING STATIONS CIRCULATE A SPECIAL BIT PATTERN THAT GRANTS ACCESS TO THE COMMUNICATIONS PATHWAY TO ANY STATION THAT HOLDS THE SEQUENCE; OFTEN USED IN NETWORKS WITH A RING TOPOLOGY.
TOKEN RING: A LOCAL NETWORK ACCESS MECHANISM AND TOPOLOGY IN WHICH A SUPERVISORY FRAME OR TOKEN IS PASSED FROM STATION TO STATION IN SEQUENTIAL ORDER. STATIONS WISHING TO GAIN ACCESS TO THE NETWORK MUST WAIT FOR THE TOKEN TO ARRIVE BEFORE TRANSMITTING DATA. IN A TOKEN RING, THE NEXT LOGICAL STATION IS ALSO THE NEXT PHYSICAL STATION ON THE RING.
TOP: TECHNICAL OFFICE PROTOCOLS DEVELOPED BY BOEING.
TRANSPARENT MODE: TRANSMISSION OF BINARY DATA WITH THE RECOGNITION OF MOST CONTROL CHARACTERS SUPRESSED. IN BINARY SYNCHRONOUS COMMUNICATIONS, ENTRY TO AND EXIT FROM THE TRANSPARENT MODE IS INDICATED BY THE SEQUENCES DLE-STX AND DLE-ETX (OR DLE-ETC, DLE-ITB, ENQ).
TRUNK: A SINGEL CIRCUIT BETWEEN TWO POINTS, BOTH OF WHICH ARE SWITCHING CENTERS OR INDIVIDUAL DISTRIBUTION POINTS.
TWO-WIRE: TWO-WIRE CIRCUIT. CIRCUIT FORMED BY TWO CONDUCTORS INSULATED FROM EACH OTHER THAT CAN BE USED AS A ONE-WAY TRANSMISSION PATH, A HALF-DUPLEX PATH, OR DUPLEX PATH.
UDLC: UNIVERSAL DATA LINK CONTROL. A BIT-ORIENTED PROTOCOL BASED ON HDLC DEVELOPED BY SPERRY UNIVAC (NOW UNISYS.)
UHF: ULTRA HIGH FREQUENCY. PORTION OF THE ELECTROMAGNETIC SPECTRUM RANGING FROM ABOUT 300 MHZ TO ABOUT 3 GHZ. THE FREQUENCY BAN INCLUDES TELEVISION AND CELLULAR RADIO FREQUENCIES.
UNIX: A MULTIUSER OPERATING SYSTEM DEVELOPED BY BELL LABORATORIES.
UPLINK: THE PORTION OF A SATELLITE CIRCUIT EXTENDING FROM AN EARTH STATION TO THE SATELLITE.
UPS: UNINTERRUPTIBLE POWER SUPPLY. USUALLY INCLUDES AN INVERTER, DRAWING ITS POWER FROM BATTERIES, WHICH GENERATES AN EXTREMELY "WELL-BEHAVED" AC POWER SIGNAL FOR A PBX OR OTHER EQUIPMENT. THE UPS COST IS RELATED TO THE AMOUNT OF POWER NEEDED AND THE LENGHT OF TIME IT MUST OPERATE DURING A FAILURE. IF A PARTICULARLY HEAVY DEMAND IS ANTICIPATED, THE SYSTEM CAN BE COUPLED WITH AN AUXILIARY GENERATOR THAT IS STARTED WHEN COMMERCIAL POWER IS INTERRUPTED.
V.21: CCITT RECOMMENDATION. 300 BPS MODEM STANDARDIZED FOR USE IN GENERAL SWITCHED TELEPHONE NETWORK.
V.22: CCITT RECOMMENDATION. STANDARDIZATON OF MODULATION RATES AND DATA-SIGNALING RATES FOR SYNCHRONOUS DATA TRANSMISSON IN THE GENERAL SWITCHED TELEPHONE NETWORK.
V.29: CCITT RECOMMENDATION. 9600 BIT/S MODEM STANDARDIZED FOR USE ON POINT-TO-POINT 4 WIRE LEASED TELEPHONE CIRCUITS.
VAN: VALUE-ADDED NETWORK. A PUBLIC DATA COMMUNICATIONS NETWORK THAT PROVIDES BASIC TRANSMISSION FACILITIES (GENERALLY LEASED BY THE VAN VENDOR FROM A COMMON CARRIER) PLUS ADDITIONAL, "ENHANCED" SERVICES SUCH AS COMPUTERIZED SWITCHING, TEMPORARY DATA STORAGE, PROTOCOL CONVERSION, ERROR DETECTION AND CORRECTION, ELECTRONIC MAIL SERVICE, ETC.
VDT: 1) VIDEO DISPLAY TERMINAL. 2) VISUAL DISPLAY TERMINAL.
VHF: VERY HIGH FREQUENCY. PORTION OF THE ELECTROMAGNETIC SPECTRUM WITH FREQUENCIES BETWEEN ABOUT 30 MHZ AND 300 MHZ. OPERATING BAND FOR RADIO AND TELEVISON CHANNELS.
VIRTUAL CIRCUIT: A CONNECTION BETWEEN A SOURCE AND A SINK IN A PACKET SWITCHING NETWORK THAT MAY BE REALIZED BY DIFFERENT CIRCUIT CONFIGURATIONS DURING TRANSMISSION OF A MESSAGE. ALSO CALLED LOGICAL CIRCUIT.
VLSI: VERY LARGE SCALE INTERGRATION.
VOICE GRADE CHANNEL: A CHANNEL USED FOR SPEECH TRANSMISSION USUALLY WITH AN AUDIO FREQUENCY RANGE OF 300-3300 HERTZ. CALLED TYPE 3002 CIRCUIT BY AT&T.
VOLATILE STORAGE: MEMORY THAT LOSES ITS CONTENTS WHEN ELECTRICAL POWER IS REMOVED.
VSAT: VERY SMALL APERTURE TERMINAL. AN EARTH STATION WITH A SMALL ANTENNA, USUALLY 6 METERS OR LESS. VSAT'S ARE TYPICALLY USED IN POINT-TO-MULTIPOINT DATA NETWORKS.
VTAM: VIRTUAL TELECOMMUNICATIONS ACCESS METHOD. AN IBM COMMUNICATIONS I/O CONTROL PROGRAMMING SOFTWARE THAT USES VIRTUAL TECHNIQUES.
WATS: WIDE AREA TELEPHONE SERVICE. A SERVICE PROVIDED BY TELEPHONE COMPANIES IN THE UNITED STATES THAT PERMITS A CUSTOMER TO MAKE CALLS TO OR FROM TELEPHONES IN SPECIFIC ZONES, WITH A DISCOUNTED MONTHLY CHARGE BASED UPON CALL VOLUME.
WIDE AREA TELEPHONE SERVICE: A SERVICE PROVIDED BY TELEPHONE COMPANIES IN THE UNITED STATES THAT PERMITS A CUSTOMER TO MAKE CALLS TO OR FROM TELEPHONES IN SPECIFIC ZONES, WITH A DISCOUNTED MONTHLY CHARGE BASED UPON CALL VOLUME.
WINDOW: THE MECHANISM USED FOR FLOW CONTROL IN A PACKET SWITCHED NETWORK TO PREVENT OVERLOAD IN THE NETWORK. THE WINDOW SIZE INDICATES THE NUMBER OF PACKETS A USER CAN HAVE OUTSTANDING (UNACKNOWLEDGED) IN A NETWORK AT ANY GIVEN TIME.
X.21: INTERFACE BETWEEN DATA TERMINAL EQUIPMNET (DTE) AND DATA CIRCUIT-TERMINATING EQUIPMENT (DCE) FOR SYNCHRONOUS OPERATION ON PUBLIC DATA NETWORKS. SPECIFIES PROTOCOLS FOR ALL THREE LOWEST LAYERS OF OSI. EFFICIENT TRANSFER OF DATA BIT STREAMS (UNBLOCKED) BETWEEN THE DTE AND DCE. ONLY USED FOR LINK ESTABLISHMEN/DISESTABLISHMENT AND OTHER CONNECTION CONTROL FUNCTIONS. APPLICABLE TO BOTH LEASED LINES AND CIRCUIT SWITCHING.
X.25: INTERFACE BETWEEN DATA TERMINAL EQUIPMENT (DTE) AND DATA CIRCUIT-TERMINATING EQUIPMENT (DCE) FOR TERMINALS OPERATING IN THE PACKET MODE ON PUBLIC DATA NETWORKS. JOINTLY PRODUCED BY CCITT AND ISO. FOR AN INTERFACE ONLY.
X.28: DEFINES THE TERMINAL-PAD INTERFACE. DTE/DCE INTERFACE FOR A START-STOP MODE DATA TERMINAL EQUIPMENT ACCESSING THE PACKET ASSEMBLY/DISASSEMBLY FACILITY ON A PUBLIC DATA NETWORK SITUATED IN THE SAME COUNTRY.
X.29: DEFINES THE PAD-COMPUTER INTERFACE. PROCEDURES FOR EXCHANGE OF CONTROL INFORMATION AND USER DATA BETWEEN A PACKET ASSEMBLY/DISASEMBLY FACILITY (PAD) AND A PACKET-MODE DTE OR ANOTHER PAD.
X.3: DEFINES THE PAD PARAMETES AND OPERATION. PACKET ASSEMBLY/ DISASSEMBLY FACILITY IN A PUBLIC DATA NETWORK. X.400: A STANDARD FOR ELECTRONIC MAIL EXCHANGE; DEVELOPED BY THE CCITT.
X.75: CCITT RECOMMENDATION. TERMINAL AND TRANSIT CALL CONTROL PROCEDURE AND DATA TRANSFER SYSTEM BETWEEN PACKET SWITCHED PUBLIC DATA NETWORKS.
XENIX: A MULTIUSER OPERATING SYSTEM DEVELOPED BY MICROSOFT, INC.; A SUBSET OF UNIX.
XMODEM: AN EIGHT BIT, PUBLIC DOMAIN ERROR CHECKING PROTOCOL DEVELOPED IN THE LATE 1970'S BY WARD CHRISTENSEN. THE FILE TRANSFER PROTOCOL USES A 128-BYTE DATA BLOCK AND CRC OR CHECKSUM ERROR CHECKING METHODS.
YMODEM: A FILE TRANSFER PROTOCOL BASED ON CRC XMODEM THAT WAS DEVELOPED BY CHUCK FORSBERG. YMODEM HAS A 1024-BYTE PACKET SIZE.
ZERO SUPPRESSON: THE ELIMINATION OF NONSIGNIFICANT 0'S IN A NUMERAL.