Telecommunications — page 32 of 85

Telecommunications terms

3101. flash memory card Synonym flash card.
3102. FLASH message A category of precedence reserved for initial enemy contact messages or operational combat messages of extreme urgency. Brevity is mandatory. [JP 1-02]
3103. flash signal A loop-open signal of 300 to 1000 ms at the network interface (NI) that is generated by the network, typically under the control of the far-end customer…
3104. flat fading Fading in which all frequency components of a received radio signal vary in the same proportion simultaneously.
3105. flat rate service Telephone service in which a single payment permits an unlimited number of local calls to be made without further charge for a specified period of time.
3106. flat weighting In a noise-measuring set, a noise weighting based on an amplitude-frequency characteristic that is flat over a frequency range that must be stated.
3107. flaw 1. In computer security, an error of commission, an omission, or an oversight that allows protection mechanisms to be bypassed or disabled. 2.
3108. flaw hypothesis methodology 1. System analysis and penetration technique in which the specification and documentation for an information system (IS) are analyzed to produce a list of…
3109. Fleming's rule A rule stating that if the thumb of the right hand points in the direction of an electric current, then the curled fingers point in the direction of the…
3110. flexible disk Synonym diskette.
3111. flicker In video, any of several visual artifacts similar to (i.e., manifested as) a stroboscopic effect (jerkiness), sometimes caused by or related to vertical…
3112. flip-flop A device that may assume either one of two reversible, stable states. Note 1: The flip-flop is used as a basic control element in computer and…
3113. float operation Operation of a dc system with the battery, rectifier, and load all connected in parallel.
3114. Floating The process of an applicant deciding against locking-in an interest rate at the time of application and instead electing to float with the market until a…
3115. floating head A magnetic head floating on a layer of air away from the recording surface. Synonyms air-floating head, flying head. [ANSDIT]
3116. floating-point coding compaction Data compaction accomplished by using coefficients, a base, and exponents to specify the scale, range, or magnitude of numbers.
3117. flood projection In facsimile, the optical method of scanning in which the object is floodlighted and the scanning spot is defined by a masked portion of the illuminated…
3118. flood search routing In a telephone network, nondeterministic routing in which a dialed number received at a switch is transmitted to all switches, i.e.
3119. flooding Insertion of a large volume of data resulting in denial of service. [INFOSEC-99] Synonyms [in e-mail and forum postings] mail bombing, spamming; [in radio…
3120. flooding compound A substance surrounding the buffer tubes of a fiber-optic cable, to prevent water intrusion into the interstices in the event of a breach of the jacket.
3121. floppy disk A circular sheet of polyester coated with magnetic oxide and housed in a thin, square plastic jacket that is used as a removable data storage medium See…
3122. flops Acronym for floating-point operations per second. Note: For example, 15 Mflops equals 15 million floating-point arithmetic operations per second.
3123. flow control See transmit flow control.
3124. flow control procedure A procedure for controlling the rate of transfer of data among elements of a network, e.g.
3125. flow diagram Synonym flowchart.
3126. flowchart A graphical representation using symbols to document the flow of information, the decision-making process, and/or the sequence of operations that are to…
3127. flowline On a flowchart, a line that (a) has an indicated direction, (b) represents a connection between other symbols, and (c) indicates the sequence of…
3128. flutter Rapid variation of signal parameters, such as amplitude, phase, and frequency. Note: Examples of flutter are (a) rapid variations in received signal…
3129. Flux The amount of energy passing through a unit area (for example, 1m2) per time. On this website, we will be discussing the flux of light energy due to…
3130. flying head Synonym floating head.
3131. Flywheel Effect The damping of interior temperature fluctuations by massive construction.
3132. flywheeling Synonym flywheel effect.
3133. FM Full Mana
3134. FM blanketing That form of interference to the reception of other broadcast stations, which is caused by the presence of an FM broadcast signal of 115 dB (562 mV/m) or…
3135. FM broadcast translator See translator.
3136. FM capture effect Synonym capture effect.
3137. FM capture ratio See capture effect.
3138. FM improvement factor The quotient obtained by dividing the signal-to-noise ratio (SNR) at the output of an FM receiver by the carrier-to-noise ratio (CNR) at the input of the…
3139. FM improvement threshold The point in an FM receiver at which the peaks in the rf signal equal the peaks of the thermal noise generated in the receiver.
3140. FM threshold effect In an FM receiver, the effect produced when the desired-signal gain begins to limit the desired signal, and thus noise limiting (suppression).
3141. FM threshold extension A change in the value of the FM threshold of a receiver. Note: FM threshold extension may be obtained by decreasing the operational bandwidth, thus…
3142. FO Force Operations (PATRIOT).
3143. followup Synonym thread.
3144. Footprint The land or water area covered by a project. This includes direct physical coverage (i.e.
3145. forbidden character Synonym illegal character.
3146. forced rerouting A procedure of transferring signaling traffic from one signaling route to another, when the signaling route in use fails or is required to be cleared of…
3147. foreign exchange (FX) service A network-provided service in which a telephone in a given local exchange area is connected, via a private line, to a central office in another, i.e.
3148. foreign instrumentation signals intelligence (FISINT) Intelligence information derived from electromagnetic emissions associated with the testing and operational deployment of foreign aerospace, surface, and…
3149. form The mass or shape of an object or objects that appears unified, such as a vegetative opening in a forest, a cliff formation, or a water tank.
3150. formal proof A complete and convincing mathematical argument, presenting the full logical justification for each proof step, for the truth of a theorem or set of…
3151. formal security policy model 1. A mathematically precise statement of a system security policy. Some formal modeling techniques include: state transition models, temporal logic…
3152. formal top-level specification (FTLS) A Top-Level Specification that is written in a formal mathematical language to allow theorems showing correspondence of the system specification to its…
3153. formal verification The process of using formal proofs to demonstrate the consistency (design verification) between a formal specification of a system and a formal security…
3154. Format The internal structure of a file, which defines the way it is stored and used. Specific applications may define unique formats for their data (i.e.
3155. format converter 1. In video and television technology, a device that allows the reformatting of a digital data stream originating from one sampling structure (lines per…
3156. format structure A combination of two or more data elements grouped in a prescribed sequence. [T1.201-1987] [T1.205-1988]
3157. FORTRAN Formula Translation Language.
3158. fortuitous conductor Any conductor that may provide an unintended path for signals. Note: Examples of fortuitous conductors are water pipes, wires, cables, and metal building…
3159. fortuitous distortion Distortion resulting from causes generally subject to laws concerning random occurrences.
3160. forum A computer conference devoted to a specific subject, having an initiator, members, readers, and possibly moderators. [2382-pt.
3161. forward busying In a telecommunications system, a feature in which supervisory signals are forwarded in advance of address signals in order to seize assets of the system…
3162. forward channel The channel of a data circuit that transmits data from the originating user to the destination user.
3163. forward echo In a transmission line, an echo propagating in the same direction as the original wave and consisting of energy reflected back by one discontinuity and…
3164. forward error correction (FEC) A system of error control for data transmission wherein the receiving device has the capability to detect and correct any character or code block that…
3165. forward indicator bit (FIB) A bit in a signal unit which indicates the start of a retransmission cycle. [T1.226-1992]
3166. forward propagation ionospheric scatter (FPIS) Synonym ionospheric scatter.
3167. forward recovery The data reconstitution of a later version of data by using an earlier version and data recorded in a journal. [2382-pt.8]
3168. forward scatter The deflection--by diffraction, nonhomogeneous refraction, or nonspecular reflection by particulate matter of dimensions that are large with respect to…
3169. forward secrecy The confidence that the compromise of a long-term private key does not compromise any earlier session keys. [After X9.42]
3170. forward sequence number (FSN) A field in a signal unit used to identify the transmitted message signal units. [T1.226-1992]
3171. forward signal A signal sent in the direction from the calling to the called station, i.e., from the original data source to the original data sink.
3172. FOT Follow-On Technologies.
3173. four-wire circuit A two-way circuit using two paths so arranged that the respective signals are transmitted in one direction only by one path and in the other direction by…
3174. four-wire repeater A repeater, consisting of two amplifiers, one associated with each direction, used in a four-wire circuit.
3175. four-wire terminating set A balanced transformer used to perform a conversion between 4-wire and 2-wire operation.
3176. Fourier analysis The definition of a periodic waveform of arbitrary shape as a summation of sine waves having specific amplitudes and phases, and having frequencies…
3177. fox message A standard test message that includes all the alphanumerics on a teletypewriter and also function characteristics (yyspace, figures shift, letters shift).
3178. FPIS Abbreviation for forward propagation ionospheric scatter. See ionospheric scatter.
3179. FPS Fujita-Pearson Scale
3180. fractal A mathematical formula or algorithm that constitutes or defines an efficient way of formulating computer graphics.
3181. fractional frequency deviation Synonym fractional frequency offset.
3182. fractional frequency fluctuation The deviation of the frequency of an oscillator from its nominal constant frequency, normalized to the nominal frequency.
3183. fractional frequency offset A measure of the deviation of the frequency of a signal from a reference, expressed as a ratio.
3184. fractional T1 In telecommunications, a portion of the 1.544 Mb/s (T1-aggregate) bit stream; the available fractions being determined by the type of multiplexer used to…
3185. Fragmentation Process by which habitats are increasingly subdivided into smaller units, resulting in their increased insularity as well as losses of total habitat area.
3186. Frame The stationary portion of a window unit that is affixed to the facade and holds the sash or other operable portions of the windows.
3187. frame alignment In the reception of framed digital data, the extent to which a received frame is correctly aligned with respect to the clock at the receiver. 2.
3188. frame check sequence (FCS) See cyclic redundancy check.
3189. frame duration The time between the beginning of a frame and the end of that frame. Note: For fixed-length frames, at a fixed data rate, frame duration is constant.
3190. frame frequency Synonym frame rate.
3191. frame grabber A device that can seize and record a single frame of video information out of a sequence of many frames.
3192. frame matching The process of comparing one sequence of frames with another sequence of frames in order to determine the correspondence between frames in each sequence…
3193. frame overhead Bits (binary digits) that are added at regular intervals to a digital signal at the sending end of a digital link and used to provide network functions…
3194. frame pitch The distance, time, or number of bits between corresponding points, i.e., significant instants, in two consecutive frames. [From Weik '89]
3195. frame rate The number of frames transmitted or received per unit time. Note 1: The frame rate is usually expressed in frames per second.
3196. frame relay An interface protocol for statistically multiplexed packet-switched data communications in which (a) variable-sized packets (frames) are used that…
3197. frame relaying protocol data unit (FPDU) A data unit exchanged at the user-network interface and having a format based on that defined in CCITT Recommendation Q.921 (1988) (ANSI T1.602). [T1.
3198. frame relaying service data unit (FSDU) The data unit exchanged at the functional boundary between the core function of Q.
3199. frame size The number of octets after the address field and before the frame check sequence (FCS) field in a frame.
3200. frame slip In the reception of framed data, the loss of synchronization between a received frame and the receiver clock, causing a frame misalignment event, and…