Telecommunications terms starting with S

935 terms

SNR Signal-to-Noise Ratio
soft copy A nonpermanent display image, for example, a cathode ray tube display.
Soft Dial Tone Numbers Numbers that permit restricted dialing, such as calling emergency services and sometimes receive incoming calls (FCC 00-104, ÃÂ¶ 33).
soft limiting See limiting.
soft sectoring On magnetic disks, magnetic drums, and optical disks, the identification of sector boundaries by using recorded information.
Softswitch See Call Agent
Software Coded instructions (programs) that make a computer do useful work.
software defined radio A radio consisting of a receiver and/or a transmitter, where each has the following properties, respectively: (a) the received signal is digitized and…
software engineering (1) A discipline whose objectives are to define, create, and apply a welldefined methodology that addresses a software life cycle of planning…
software package A package that consists of (a) one or more computer programs and possibly related material such as utility programs or tutorial programs, recorded on a…
software piracy The unauthorized use, copying, or distribution of software products. [2382-pt.8]
software tool Software, such as a computer program, routine, subroutine, program block, or program module, that can be used to develop, test, analyze, or maintain a…
SOH A declaration from a client computer that asserts the computer's health status.
solid-state scanning In facsimile, scanning in which all or a part of the scanning process is performed by electronic commutation of an array of solid-state photosensitive…
soliton An optical pulse having a shape, spectral content, and power level designed to take advantage of nonlinear effects in an optical fiber waveguide, for the…
sonar An acronym derived from the expression "sound navigation and ranging." Refers to the method or equipment for determining by underwater sound techniques…
SONET Synchronous Optical Network.
sonobuoy In sonar systems, a device (a) that is used to detect acoustic waves, such as those produced by ships and submarines, (b) that, when activated, relays…
sound navigation and ranging See sonar.
sound wave See acoustic wave.
sound-powered telephone A telephone in which the operating power is derived from the speech input only.
sounder prediction station A station equipped with an ionosphere sounder for realtime monitoring of upper atmosphere phenomena or to obtain data for the prediction of propagation…
sounding A set of data measuring the vertical structure of an atmospheric parameter (temperature, humidity, pressure, winds, etc.) at a given time.
Source Any place or object from which air pollutants are released. Sources that are fixed in space are stationary sources and sources that move are mobile…
source efficiency In optical systems, the ratio of emitted optical power of a source to the input electrical power.
source language In computing, data processing, and communications systems, a language from which statements are translated.
source program A computer program written in a source language. Note: An example of a source program is a program that serves as the input to an assembler, compiler, or…
source quench A congestion-control technique in which a computer experiencing data traffic congestion sends a message back to the source of the messages or packets…
source user The user providing the information to be transferred to a destination user during a particular information transfer transaction.
space In telegraphy, one of the two significant conditions of encoding. Note 1: The complementary significant condition is called a "mark.
space diversity A method of transmission or reception, or both, in which the effects of fading are minimized by the simultaneous use of two or more physically separated…
space operation service A radiocommunication service concerned exclusively with the operation of spacecraft, in particular space tracking, space telemetry and space telecommand.
space radiocommunication Any radiocommunication involving the use of one or more space stations or the use of one or more reflecting satellites or other objects in space.
space research service A radiocommunication service in which spacecraft or other objects in space are used for scientific or technological research purposes. [NTIA] [RR]
space station A station located on an object which is beyond, is intended to go beyond, or has been beyond, the major portion of the Earth's atmosphere.
space subsystem In satellite communications, that portion of the satellite link that is in orbit.
space system Any group of cooperating Earth stations and/or space stations employing space radiocommunication for specific purposes. [NTIA] [RR] [47CFR]
space telecommand The use of radiocommunication for the transmission of signals to a space station to initiate, modify or terminate functions of equipment on an associated…
space telemetry The use of telemetry for the transmission from a space station of results of measurements made in a spacecraft, including those relating to the…
space tracking Determination of the orbit, velocity or instantaneous position of an object in space by means of radiodetermination, excluding primary radar, for the…
space-division multiplexing A misnomer. Note: Space-division multiplexing has been improperly applied to the use of multiple physical transmission channels, e.g.
space-division switching In telephony, switching in which single transmission-path routing determination is accomplished in a switch by using a physically separated set of matrix…
spacecraft A man-made vehicle which is intended to go beyond the major portion of the Earth's atmosphere. [NTIA] [RR] [47CFR]
spacing bias The uniform lengthening of all spacing signal pulses at the expense of the pulse width of all marking signal pulses.
spacing end distortion See end distortion.
spacing pulse Synonym yyspace.
spacing signal Synonym yyspace.
Spam Unelicited emails in large quantities; rapidly repeated scrolling text.
Spamming See spamdexing. Spamming is also used more generally to refer to the sending of unsolicited bulk electronic mail, and the search engine use is derived…
spare An individual part, subassembly, or assembly supplied for the maintenance or repair of systems or equipment.
spatial application An application requiring high spatial resolution, possibly at the expense of reduced temporal positioning accuracy, i.e., increased jerkiness.
spatial coherence See coherent.
spatial edge noise In a video display, that form of edge busyness that is characterized by spatially varying distortion that occurs in close proximity to the edges of…
spatially coherent radiation See coherent.
special grade access line In the Defense Switched Network, an access line specially conditioned, usually by providing amplitude and delay equalization, to give it characteristics…
special grade of service In the Defense Switched Network, a network-provided service in which specially conditioned interswitch trunks and access lines are used to provide secure…
special information tone (SIT) A tone that comprises three precise sequential frequencies used to identify recorded announcements. [After T1.207-1998]
special interest group See community of interest, interest group, forum, SIG.
special purpose computer A computer that is designed to operate on a restricted class of problems.
special service A radiocommunication service, not otherwise defined in this Section [of the Radio Regulations], carried on exclusively for specific needs of general…
special services All services other than message telephones, e.g., teletypewriter exchange service (TWX), private line services. [47 CFR Pt.36-A]
specialized common carrier (SCC) A common carrier offering a limited type of service or serving a limited market.
specific detectivity For a photodetector, a figure of merit used to characterize performance, equal to the reciprocal of noise equivalent power (NEP), normalized to unit area…
specification a written description of the invention and the manner and process of making and using the same -- see MPEP 608.01 for more
specification point An industry agreed-upon location where a set of specifications would apply, for example, the node in the originating network where specification occurs.
speckle noise Synonym modal noise.
speckle pattern In optical systems, a field-intensity pattern produced by the mutual interference of partially coherent beams that are subject to minute temporal and…
spectral bandwidth See spectral width.
Spectral Density A radar term for the distribution of power by frequency.
Spectral Irradiance The monochromatic irradiance of a surface per unit bandwidth at a particular wavelength, usually expressed in Watts per square meter-nanometer bandwidth.
Spectral Line An emission (bright) or absorption (dark) of light at a specific frequency or wavelength.
spectral loss curve Of an optical fiber, a plot of attenuation as a function of wavelength. Note: Spectral loss curves must be normalized with respect to distance before…
spectral purity The degree to which a signal is monochromatic.
spectral radiance Radiance per unit wavelength interval at a given wavelength, expressed in watts per steradian per unit area per wavelength interval.
spectral responsivity The ratio of an optical detector's electrical output to its optical input, as a function of optical wavelength.
spectral width A measure of the spread of the Doppler spectrum and consequently is sensitive to the spread in the particle size spectra.
spectral window See window.
Spectrum Electromagnetic radiation arranged in order of wavelength from Ion wavelength radio waves to short wavelength gamma rays.
spectrum designation of frequency See electromagnetic spectrum.
spectrum signature The pattern of radio signal frequencies, amplitudes, and phases, which pattern characterizes the output of a particular device and tends to distinguish it…
Specular reflection Also known as direct reflection, regular reflection, or mirror reflection. The reflection of electromagnetic rays without scattering or diffusion.
speech digit signaling Synonym bit robbing.
speech level The power in dBm of a speech signal measured using a technique equivalent to Method B of ITU-T Recommendation P.56. [T1.255-1997]
speech power See volume unit.
speech privacy Techniques using fixed sequence permutations or voice/speech inversion to render speech unintelligible to the casual listener. [INFOSEC-99]
speech synthesizer A device that is capable of accepting digital or analog data and developing intelligible speech sounds that correspond to the input data, without…
speech-plus Pertaining to a circuit that was designed and used for speech transmission, but to which other uses, such as digital data transmission, facsimile…
speech-plus-duplex operation Operation in which speech and telegraphy (duplex or simplex) are transmitted simultaneously over the same circuit, and mutual interference is eliminated…
speech-plus-signaling Pertaining to equipment that permits the use of part of a voice-frequency band for signaling.
speech-to-speech-correlated-noise ratio (Q) The ratio of the speech power to the power of speech-correlated noise in a digital transmission system. [T1.501-1988]
speed calling A service feature that enables a switch or station to store certain telephone numbers and dial them automatically when a short (1-, 2-, or 3-digit) code…
speed dialing 1. Synonym abbreviated dialing. 2. Dialing at a speed greater than the normal ten pulses per second.
speed of light (c) The speed of an electromagnetic wave in free space, precisely 299,792,458 m/s. Note 1: The preceding figure is precise because by international agreement…
speed of service The time between release of a message by the originator to receipt of the message by the addressee, as perceived by the end user.
speed-up tone Synonym camp-on busy signal.
Spider Search engine crawlers which search or "spider" the web for pages to include in the index.
spike 1. An inflorescence in which the main axis is elongated and the flowers are sessile. 2.
spike file See last-in first-out.
spill forward In automatic switching, the transfer of full control on a call to the succeeding office by sending forward the complete telephone address of the called…
spill-forward feature A service feature, in the operation of an intermediate office, that, acting on incoming trunk service treatment indications, assumes routing control of…