Telecommunications — page 74 of 85

Telecommunications terms

7301. stroke width In character recognition, the distance between the two edges of a stroke, measured perpendicular to the stroke centerline.
7302. strong authentication Authentication by means of cryptographically derived credentials. [After X.509]
7303. structured development Development of a system or part of a system where components at lower levels are traceable from those at the higher level [CESG].
7304. structured programming A style of programming usually associated with languages such as C, Fortran, Pascal and so on.
7305. structured text Text for which a well-defined, unambiguous internal structure is defined. Such text shall be human readable and interpreted identically by all conforming…
7306. STU Secure Telephone Unit.
7307. stub network A network that conveys data only among local hosts. Note: Even if the local hosts are connected to more than one other network, these hosts do not carry…
7308. studio-to-transmitter link (STL) A communications link used for the transmission of broadcast material from a studio to the transmitter.
7309. stuffing See bit stuffing, de-stuffing.
7310. stunt box A device that controls the nonprinting functions of a printer at a terminal.
7311. STX Abbreviation for start-of-text character.
7312. SUB Under or subordinate to.
7313. sub-band adaptive differential pulse code modulation (SB-ADPCM) Modulation in which (a) an audio frequency band is split into two sub-bands, i.e.
7314. sub-registration authority (SRA) [An] Individual with primary responsibility for managing the distinguished name process. [INFOSEC-99]
7315. Subassembly Two or more parts joined together to form a unit, capable of disassembly, which is only a part of a complete machine, structure, or other article.
7316. subcarrier A carrier used to modulate another carrier. Note: The modulated carrier can be used to modulate another carrier, and so on, so that there can be several…
7317. subclass Each asset class - stock, bonds, and cash equivalents, for example - is made up of a number of different groups of investments called subclasses.
7318. Subject The Subject of an email message should be a short summary of its contents. Email clients usually display it in a mailbox display together with the sender.
7319. subject authority An authority recognized in a Security Domain as a trusted source of security information concerning security subjects (human beings and Applications)…
7320. Subject Security Level A subject's security level is equal to the security level of the objects to which it has both read and write access.
7321. sublayer In a layered open communications system, a specified subset of the services, functions, and protocols included in a given layer. 2.
7322. Subnet Address In computer networks, a subnetwork or subnet is a range of logical addresses within the address space that is assigned to an organization.
7323. subnet mask A number that is used to identify a subnetwork so that IP addresses can be shared on a local area network.
7324. subnetwork 1. A collection of equipment and physical transmission media that forms an autonomous whole and that can be used to interconnect systems for purposes of…
7325. subordinate station Synonym slave station.
7326. subroutine A named or otherwise accessible piece of program that can be invoked from elsewhere in the program in order to accomplish some sub-goal of the program.
7327. subscribe In computer conferencing, to add one's address to a distribution list, or to join a forum. [2382-pt.35]
7328. Subscriber A party who receives a credential or token from a CSP and becomes a claimant in an authentication protocol.
7329. subscriber data key See subscriber key.
7330. subscriber key A key encrypting key or data key transported in a multiple center CSM for eventual distribution to a pair of subscribers. [After X9.28]
7331. subscriber line Synonym loop. 2. A communication channel between a telephone station, PBX or TWX station and the central office which serves it. Synonym exchange line.
7332. Subscriber Line Charge (SLC) A monthly fee paid by telephone subscribers that is used to compensate the local telephone company for part of the cost of installation and maintenance of…
7333. substitute character (SUB) A control character that is used in the place of a character that is recognized to be invalid or in error or that cannot be represented on a given device.
7334. substitution method In optical fiber technology, a method of measuring the transmission loss by (a) using a stable optical source, at the wavelength of interest, to drive a…
7335. subtributary office A class of tributary office which does not have direct access to its toll center, but which is connected to its toll center office by means of circuits…
7336. subvoice-grade channel A channel with a bandwidth narrower than that of a voice-grade channel. Note: A subvoice-grade channel is usually a subchannel of a voice-grade line.
7337. successful block delivery The transfer of a nonduplicate user information block between the source user and intended destination user.
7338. successful block transfer The transfer of a correct, nonduplicate, user information block between the source user and intended destination user.
7339. successful disengagement The termination of user information transfer between a source user and a destination user in response to a disengagement request.
7340. Sudden Ionospheric Disturbance (SID) In solar-terrestrial terms, HF propagation anomalies due to ionospheric changes resulting from solar flares, proton events and geomagnetic storms.
7341. suitability of function An aspect of the assessment of the effectiveness of a Target of Evaluation, namely the suitability of its security enforcing functions and mechanisms to…
7342. sum check Synonym summation check.
7343. summation check 1. A check based on the formation of the sum of the digits of a numeral. Note: The sum of the individual digits is usually compared with a previously…
7344. Sunspot Dark areas on the Sun created by strong magnetic fields beneath the Sun’s surface.
7345. super high frequency (SHF) See electromagnetic spectrum.
7346. superclass A class from which a particular class is derived, perhaps with one or more classes in between. See also subclass, subtype.
7347. superencryption [The] process of encrypting encrypted information. Note: [This process] occurs when a message, encrypted off-line, is transmitted over a secured, on-line…
7348. superframe (SF) In T-carrier, a synchronization frame that delineates 12 DS1 frames. [J. Beaty, FAA] 2.
7349. supergroup See group, multiplex hierarchy.
7350. supergroup distribution frame (SGDF) In frequency-division multiplexing (FDM), the distribution frame that provides terminating and interconnecting facilities for group modulator output…
7351. superhighway See National Information Infrastructure.
7352. superluminescent LED A light-emitting diode in which there is stimulated emission with amplification but insufficient feedback for oscillations to build up to achieve lasing…
7353. Superradiance The process used by a superradiant laser to generate or amplify a laser beam in a single pass through a lasant material, or, in the case of a free…
7354. supersector An oversized sector written on a diskette, as part of a method of copy protection. [2382-pt.8]
7355. supersession [In security,] scheduled or unscheduled replacement of a COMSEC aid with a different edition. [INFOSEC-99]
7356. superuser The person whom the "operating system" will let do almost anything. Typically your system administrator or someone pretending to be your system…
7357. supervisor Synonym supervisory program.
7358. supervisor state Synonym executive state.
7359. Supervisory control A system used to monitor conditions and operate mechanical features associated with a facility from a location other than at the site.
7360. supervisory program A program, usually part of an operating system, that controls the execution of other routines and regulates work scheduling, input-output operations…
7361. supervisory routine Synonym supervisory program.
7362. supervisory signaling Specific electrical conditions (called "on-hook" and "off-hook") at the NI (network interface) that are used to control call states and processes. [T1.
7363. supervisory signals Signals used to indicate, or to indicate and control, the various operating states of the circuits or circuit combinations involved in a particular…
7364. supportive security application Specific type of application that provides security services or security management capabilities at application level rather than embedded in the…
7365. suppressed carrier single-sideband emission A single-sideband emission in which the carrier is virtually suppressed and not intended to be used for demodulation. [NTIA] [RR]
7366. suppressed carrier transmission Amplitude modulation (AM) transmission in which the carrier level is reduced below that required for demodulation.
7367. suppression measure [An] Action, procedure, modification, or device that reduces the level of, or inhibits the generation of, compromising emanations in an information system…
7368. surf Slang. To search the Web, by navigating in a nonlinear and seemingly random way, often without a specific objective.
7369. surface refractivity The refractive index of the Earth's atmosphere, calculated from observations of pressure, temperature, and humidity at the surface of the Earth.
7370. surface wave A wave that is guided along the interface between two different media or by a refractive index gradient.
7371. Surge A rapid increase in the depth of flow.
7372. surge protective device (SPD) An assembly of one or more components intended to limit or divert surges; the device contains at least one nonlinear component. [T1.
7373. surge suppressor Synonyms arrester, surge protective device, surge protector.
7374. surrogate access See discretionary access control.
7375. Surveillance (ser-VAY-lents) In medicine, the ongoing collection of information about a disease, such as cancer, in a certain group of people.
7376. Survey A precise measurement of a property by a licensed surveyor, showing legal boundaries of a property and the dimensions and location of improvements.
7377. survivability A property of a system, subsystem, equipment, process, or procedure that provides a defined degree of assurance that the named entity will continue to…
7378. survivable operation See survivability.
7379. survival craft station A mobile station in the maritime mobile service or the aeronautical mobile service intended solely for survival purposes and located on any lifeboat…
7380. susceptibility In electronic warfare, the degree to which electronic equipment is affected by electromagnetic energy radiated by an enemy's equipment, such as jamming…
7381. susceptibility threshold 1. The amount of undesired signal power required at the input terminals of a receiver to cause barely perceptible interference at the receiver output…
7382. susceptiveness In telephone systems, the extent to which circuits pick up noise and low-frequency energy by induction from power systems.
7383. sweep acquisition A technique whereby the frequency of the local oscillator is slowly swept past the reference in order to assure that the pull-in range is reached.
7384. Sweep Jamming A narrow band of jamming that is back and forth over a relatively wide operating band of frequencies.
7385. swim Slow, graceful, undesired movements of display elements, groups, or images about their mean position on a display surface, such as that of a monitor.
7386. switch A Java keyword used to evaluate a variable that can later be matched with a value specified by the case keyword in order to execute a group of statements.
7387. switch busy hour In telephony, the busy hour for a single switch.
7388. switchboard Equipment used for manual switching operations.
7389. switched access line A communication path between local exchange and a customer interface (CI). [T1.401-1988]
7390. switched circuit In a communications network, a circuit that may be temporarily established at the request of one or more of the connected stations.
7391. switched connection See switched circuit.
7392. Switched Digital Acceptance Testing (SDAT) Describes acceptance testing procedures used when Switched Access Services are provided with a digital switch on digital facilities.
7393. switched exchange access network The network of switching systems, interconnecting facilities, and equipment provided by an exchange carrier (EC) to provide telecommunications services…
7394. switched loop In telephony, a circuit that automatically releases a connection from a console or switchboard, once the connection has been made to the appropriate…
7395. switched multimegabit data services (SMDS) A connectionless, broadband, packet-switched data service that provides LAN-like performance and features in metropolitan or wide areas.
7396. switched network A communications network, such as the public switched telephone network, in which any user may be connected to any other user through the use of message…
7397. switching The controlling or routing of signals in circuits to execute logical or arithmetic operations or to transmit data between specific points in a network.
7398. switching center In communications systems, a facility in which switches are used to interconnect communications circuits on a circuit-, message-, or packet-switching…
7399. switching exchange Synonym switching center.
7400. switching facility Synonym switching center.