Telecommunications — page 31 of 85

Telecommunications terms

3001. FDMA Abbreviation for frequency-division multiple access.
3002. FDX Full Duplex (Telecomm/Computer term).
3003. feature code A code (or codes) used to select/activate a service feature (e.g., forwarding, using two- or three-digit codes preceded by * or 1 1 or #, and which may…
3004. FEC Abbreviation for forward error correction.
3005. Federal Communications Commission See FCC.
3006. Federal Networking Council (FNC) The body responsible for coordinating networking needs among U.S. Federal agencies.
3007. Federal Telecommunications System (FTS) A switched long-distance telecommunications service formerly provided for official Federal Government use.
3008. Federal Telecommunications System 2000 service See FTS2000.
3009. Feed A component that "feeds" the signal from the optical system to the amplification electronics. Also called a "feed horn" or "horn".
3010. feed-forward path In the encoder, the signal path from the input of the PCM-to-uniform-PCM converter to the output of the adaptive quantizer.
3011. feedback the process by which an initial change brings about additional change that either reinforces or counteracts the initial change.
3012. feedback path The signal path from the input of the bit-masking block to the output of the adaptive predictor. [T1.310-1991]
3013. feeder echo noise Signal distortion resulting from reflected waves in a transmission line that is many wavelengths long and mismatched at both the generator and the load…
3014. feeder link A radio link from an Earth station at a given location to a space station, or vice versa, conveying information for a space radiocommunication service…
3015. Fence The boundary of a trusted region [CESG].
3016. fence penetrability The ability of features outside a trusted region to penetrate a fence - thus leading to a potential or actual breach of the System Security Policy [CESG].
3017. FEP Abbreviation for front-end processor.
3018. Fermat's principle A principle stating that a ray of light follows the path that requires the least time to travel from one point to another, including reflections and…
3019. FET photodetector A photodetector using photogeneration of carriers in the channel region of a field-effect transistor structure to provide photodetection with current gain.
3020. fetch protection [An] AIS-provided restriction to prevent a program from accessing data in another user's segment of storage. [NIS] 2.
3021. fiber (FY-ber) In food, fiber is the part of fruits, vegetables, legumes, and whole grains that cannot be digested. The fiber in food may help prevent cancer.
3022. fiber amplifier A device that amplifies an optical signal directly, without the need to convert it to an electrical signal, amplify it electrically, and reconvert it to…
3023. fiber axis The longitudinal center of symmetry of an optical fiber, i.e., the locus of points that are determined by the centers of mechanical symmetry of the…
3024. fiber bandwidth See bandwidth (of an optical fiber).
3025. fiber buffer See buffer.
3026. fiber cable See fiber optic cable.
3027. fiber cutoff wavelength (λcf) See cutoff wavelength.
3028. fiber dispersion See dispersion.
3029. Fiber Distributed Data Interface (FDDI) (FDDI) A media access (transmission) control-level protocol with token-ring architecture, a communication bandwidth of 100 Mbps and supported on a fiber network…
3030. fiber optic bus See bus.
3031. fiber optic cable A telecommunications cable in which one or more optical fibers are used as the propagation medium.
3032. fiber optic isolator See optical isolator.
3033. fiber optic link A communications link that transmits signals by means of modulated light propagated in an optical fiber.
3034. fiber optics (FO) The branch of optical technology concerned with the transmission of light through fibers made of transparent materials such as glasses and plastics.
3035. fiber pigtail See pigtail.
3036. fidelity The degree to which a system, or a portion of a system, accurately reproduces, at its output, the essential characteristics of the signal impressed upon…
3037. FidoNet A network designed for e-mail distribution through individual bulletin board systems rather than through Internet servers.
3038. field Field A region of space at each point of which a given physical or mathematical quantity has some definite value.
3039. field intensity The irradiance of an electromagnetic wave under specified conditions. Note: Field intensity is usually expressed in watts per square meter.
3040. field strength 1. The magnitude of an electric, magnetic, or electromagnetic field at a given point.
3041. field tag Synonym flag.
3042. field wire A flexible insulated wire used in field telephone and telegraph systems. Note 1: WD-1 and WF-16 are types of field wire.
3043. field-disturbance sensor A restricted radiation device which establishes a radio frequency field in its vicinity and detects changes in that field resulting from the movement of…
3044. FIFO First In, First Out. See also "LIFO". Also, a nickname for a "named pipe".
3045. file To place a paper in the official custody of the clerk of court/court administrator to enter into the files or records of a case.
3046. file ACL class The property of a file indicating access permissions for a process related to the process' user or group identification.
3047. file archive Synonym FTP archive.
3048. file name extension A suffix that is preceded by a decimal (".") and that is appended to a computer file name. Note: Common filename extensions with their meanings are: .
3049. file other class The property of a file indicating access permissions for a process related to the process' user and group identification.
3050. file privilege attribute A per-file privilege value that specifies global behavior for all privileges defined in the implementation [POSIX.6].
3051. file privilege flag A per-privilege attribute of a file that is used during exec() processing in computing the privileges of any process executing that file [POSIX.6].
3052. file privilege state A state variable that identifies a value for all defined file privilege flags for all privileges defined in an implementation and a value for all file…
3053. file protection The execution of appropriate administrative, technical, or physical means to guard against the unauthorized access to, modification of, or deletion of a…
3054. file security [A] means by which access to computer files is limited to authorized users only. [INFOSEC-99]
3055. File Server When several or many computers are networked together in a LAN situation, one computer may be utilized as a storage location for files for the group.
3056. file site Synonym FTP archive.
3057. file transfer Moving named files from one computer or network to another
3058. File Transfer Protocol (FTP) (FTP) A method of data transfer that can take place between Frame Relay Networks, and Workstations.
3059. file transfer, access, and management (FTAM) An application's service and protocol based on the concept of virtual file store.
3060. file-oriented applications Applications concerned with the storage, manipulation, and exchange of information between application processes in the form of files. [T1.210-1993]
3061. Fill Man-made deposits of soil and rock and/or waste material.
3062. fill bit See bit stuffing.
3063. fill device [A] COMSEC item used to transfer or store key in electronic form or to insert key into a crypto-equipment. [INFOSEC-99]
3064. fill-in area The area where the coverage contour of an FM translator or booster station is within the protected contour of the associated primary station (i.e.
3065. fill-in signal unit (FISU) A signal unit that is transmitted when there are no message signal units or link status signal units to be transmitted.
3066. filled cable A cable that has a nonhygroscopic material, usually a gel, inside the jacket or sheath.
3067. FILO Abbreviation for first-in last-out.
3068. filter A criterion you specify to limit the results when you list or describe your Amazon EC2 resources.
3069. filtered symmetric differential phase-shift keying (FSDPSK) A method of encoding information for digital transmission in which (a) a binary 0 is encoded as a +90° change in the carrier phase and a binary 1 is…
3070. final trunk group A last-choice trunk group that receives overflow traffic, may receive first-route traffic and for which there is no alternate route.
3071. finger A computer-operating-system command for accessing limited network-user-account information.
3072. finished call In an information transaction, a call in which the call originator or call receiver terminates the communication and goes on hook, i.e., hangs up. 2.
3073. FIP Federal Information Processing.
3074. FIP equipment In the Federal government, any equipment or interconnected system or subsystems of equipment (as defined in 41CFR) used in the automatic acquisition…
3075. FIP system In the Federal government, any organized combination of FIP equipment, software, services, support services, or related supplies.
3076. FIREFLY [A] key management protocol based on public key cryptography. [INFOSEC-99]
3077. Firewall A set of related programs that protect the resources of a private network from users from other networks.
3078. Firmware The programs and data components of a cryptographic module that are stored in hardware within the cryptographic boundary and cannot be dynamically written…
3079. first window Of silica-based optical fibers, the transmission window at approximately 830 to 850 nm. [FAA]
3080. first-in first-out (FIFO) A queuing discipline in which entities in a queue leave the queue in the same order in which they arrive.
3081. first-in last-out (FILO) A queuing discipline in which entities in a queue leave the queue in the reverse order from that in which they arrived.
3082. first-route traffic Traffic that has not been route-advanced at any switching system. [T1.Rpt 11-1991]
3083. FISINT Acronym for foreign instrumentation signals intelligence.
3084. five-hundred (500) service A telephone service that allows individuals to receive, via a single number, telephone calls in various locations (e.g.
3085. fixed access In personal communications service (PCS), terminal access to a network in which there is a set relationship between a terminal and the access interface.
3086. fixed attenuator See pad.
3087. fixed loop A service feature that permits an attendant on an assisted call to retain connection through the attendant position for the duration of the call.
3088. fixed microwave auxiliary station A fixed station used in connection with (a) the alignment of microwave transmitting and receiving antenna systems and equipment, (b) coordination of…
3089. fixed service (FX) A radiocommunication service between specified fixed points. [NTIA] [RR] [47CFR]
3090. fixed station A station in the fixed service. [NTIA] [RR] [47CFR] 2. The term "fixed station" in the fixed public or fixed public press service includes all apparatus…
3091. fixed storage Synonym read-only storage.
3092. fixed-reference modulation Modulation in which the significant condition for any signal element is based on a fixed reference.
3093. fixed-satellite service A radiocommunication service between Earth stations at given positions when one or more satellites are used; the given position may be a specified fixed…
3094. fixed-tolerance-band compaction Data compaction accomplished by storing or transmitting data only when the data fall outside prescribed limits.
3095. flag See affinity tag.
3096. flag sequence In data transmission or processing, a sequence of bits used to delimit, i.e. mark, the beginning and end of a frame.
3097. Flame An insulting criticism or remark meant to incite anger.
3098. Flash A sudden, brief illumination of a conductive channel associated with lightning, which may contain multiple strokes with their associated stepped leaders…
3099. flash card In computer-based equipment (such as MP3 players, digital cameras, and palm-held computers), a type of memory storage device approximately the size of a…
3100. flash feature A supplementary calling feature provided by the near-end customer interface (CI) that is activated or controlled through the use of one or more flash…