Supervisory controlA system used to monitor conditions and operate mechanical features associated with a facility from a location other than at the site.
supervisory programA program, usually part of an operating system, that controls the execution of other routines and regulates work scheduling, input-output operations…
supervisory signalingSpecific electrical conditions (called "on-hook" and "off-hook") at the NI (network interface) that are used to control call states and processes. [T1.
supervisory signalsSignals used to indicate, or to indicate and control, the various operating states of the circuits or circuit combinations involved in a particular…
supportive security applicationSpecific type of application that provides security services or security management capabilities at application level rather than embedded in the…
suppressed carrier single-sideband emissionA single-sideband emission in which the carrier is virtually suppressed and not intended to be used for demodulation. [NTIA] [RR]
suppressed carrier transmissionAmplitude modulation (AM) transmission in which the carrier level is reduced below that required for demodulation.
suppression measure[An] Action, procedure, modification, or device that reduces the level of, or inhibits the generation of, compromising emanations in an information system…
surfSlang. To search the Web, by navigating in a nonlinear and seemingly random way, often without a specific objective.
surface refractivityThe refractive index of the Earth's atmosphere, calculated from observations of pressure, temperature, and humidity at the surface of the Earth.
surface waveA wave that is guided along the interface between two different media or by a refractive index gradient.
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.
Surveillance(ser-VAY-lents) In medicine, the ongoing collection of information about a disease, such as cancer, in a certain group of people.
SurveyA precise measurement of a property by a licensed surveyor, showing legal boundaries of a property and the dimensions and location of improvements.
survivabilityA property of a system, subsystem, equipment, process, or procedure that provides a defined degree of assurance that the named entity will continue to…
survival craft stationA mobile station in the maritime mobile service or the aeronautical mobile service intended solely for survival purposes and located on any lifeboat…
susceptibilityIn electronic warfare, the degree to which electronic equipment is affected by electromagnetic energy radiated by an enemy's equipment, such as jamming…
susceptibility threshold1. The amount of undesired signal power required at the input terminals of a receiver to cause barely perceptible interference at the receiver output…
susceptivenessIn telephone systems, the extent to which circuits pick up noise and low-frequency energy by induction from power systems.
sweep acquisitionA 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.
Sweep JammingA narrow band of jamming that is back and forth over a relatively wide operating band of frequencies.
swimSlow, graceful, undesired movements of display elements, groups, or images about their mean position on a display surface, such as that of a monitor.
switchA 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.
switch busy hourIn telephony, the busy hour for a single switch.
switchboardEquipment used for manual switching operations.
switched access lineA communication path between local exchange and a customer interface (CI). [T1.401-1988]
switched circuitIn a communications network, a circuit that may be temporarily established at the request of one or more of the connected stations.
Switched Digital Acceptance Testing (SDAT)Describes acceptance testing procedures used when Switched Access Services are provided with a digital switch on digital facilities.
switched exchange access networkThe network of switching systems, interconnecting facilities, and equipment provided by an exchange carrier (EC) to provide telecommunications services…
switched loopIn telephony, a circuit that automatically releases a connection from a console or switchboard, once the connection has been made to the appropriate…
switched multimegabit data services (SMDS)A connectionless, broadband, packet-switched data service that provides LAN-like performance and features in metropolitan or wide areas.
switched networkA 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…
switchingThe controlling or routing of signals in circuits to execute logical or arithmetic operations or to transmit data between specific points in a network.
switching centerIn communications systems, a facility in which switches are used to interconnect communications circuits on a circuit-, message-, or packet-switching…
SXSAbbreviation for step-by-step switching system.
syllabary[A] list of individual letters, combination of letters, or syllables, with their equivalent code groups, used for spelling out words or proper names not…
syllableA character string or a bit string in a word.
symbolic languageA computer programming language used to express addresses and instructions with symbols convenient to humans rather than to machines.
symbolic logicThe discipline in which valid arguments and operations are dealt with using an artificial language designed to avoid the ambiguities and logical…
symmetric authentication methodMethod for demonstrating knowledge of a secret, in which both entities share a common authentication information [10181-2].
symmetric cryptographyCryptography in which the same key is used for encryption and decryption. [2382-pt.8]
symmetrical channelA channel in which the send and receive circuits have the same data signaling rate.
symmetrical pairA balanced transmission line, in a multipair cable, having equal conductor resistances per unit length, equal impedances from each conductor to earth, and…
symmetryThe attribute describing the relationship of information flow between two (or more) access points or reference points involved in a communication.
synchronismThe state of being synchronous. 2. For repetitive events with the same, multiple, or submultiple repetition rates, a relationship among the events such…
SynchronizationFor data streams, the process whereby a received set of data is placed in one to one correspondence with the data assumed to have been transmitted.
synchronization bitA bit used to achieve or maintain synchronism. Note: The term "synchronization bit" is usually applied to digital data streams, whereas the term…
synchronization codeIn digital systems, a sequence of bits introduced into a transmitted signal to achieve or maintain synchronism.
synchronization pulseA pulse used to achieve or maintain synchronism. Note: The term "synchronization pulse" is usually applied to analog signals, whereas the term…
synchronizingAchieving and maintaining synchronism. 2. In facsimile, achieving and maintaining predetermined speed relations between the scanning spot and the…
synchronizing pilotIn FDM, a reference frequency used for achieving and maintaining syntonization of the oscillators of a carrier system or for comparing the frequencies or…
synchronizing signalIn facsimile systems, the signal that maintains predetermined speed relations between the scanning spot and recording spot within each facsimile scanning…
synchronousProgramming in which the orderly sequence of events can be determined; that is, when things happen one after the other, not at the same time.
synchronous crypto-operation[A] method of on-line crypto-operation in which crypto-equipment and associated terminals have timing systems to keep them in step. [INFOSEC-99]
synchronous data networkA data network in which synchronism is achieved and maintained between data circuit-terminating equipment (DCE) and the data switching exchange (DSE), and…
synchronous idle character (SYN)A transmission control character used in synchronous transmission systems to provide a signal from which synchronism or synchronous correction may be…
synchronous networkA network in which clocks are controlled to run, ideally, at identical rates, or at the same mean rate with a fixed relative phase displacement, within a…
synchronous orbitAny orbit in which an orbiting object has a period equal to the average rotational period of the body being orbited, and in the same direction of rotation…
synchronous payloadsPayloads derivable from a network transmission signal by removing integral numbers of bits in every frame, i.e.
synchronous systemA system in which events, such as signals, occur in synchronism. Note 1: An example of a synchronous system is one in which a transmitter and receiver…
synchronous tandem encodingA transcoding of the form ADPCM-PCM-ADPCM (adaptive differential pulse code modulation-pulse code modulation-adaptive differential pulse code modulation)…
synchronous TDMA multiplexing scheme in which timing is obtained from a clock that controls both the multiplexer and the channel source.
Synchronous Test Line (103)The term "Synchronous Test Line" denotes an arrangement in an end office which performs marginal operational tests of supervisory and ring-tripping…
synchronous transfer modeIn a Broadband Integrated Services Digital Network (B-ISDN), a proposed transport level technique in which time-division multiplexing and switching is to…
synchronous transmissionDigital transmission in which the time interval between any two similar significant instants in the overall bit stream is always an integral number of…
synchronous transport signal level 1 (STS-1)The basic logical building block signal of synchronous optical networks (SONET). The STS-1 signal has a bit rate of 51.840 Mb/s. [T1.X1] [After T1.
syntaxFrom Greek, "with-arrangement". How things (particularly symbols) are put together with each other.
syntonizationThe process of setting the frequency of one oscillator equal to that of another.
SystemPhysically connected generation, transmission, and distribution facilities operated as an integrated unit under one central management, or operating…
system administrationIn computer technology, a set of functions that provides support services, ensures reliable operations, promotes efficient use of the system, and ensures…
system administratorThe person responsible for configuring and administering the enterprise's computers, networks, and software systems.
system analysisA systematic investigation of a real or planned system to determine the functions of the system and how they relate to each other and to any other system.
system blocking signalA control message generated within a telecommunications system to indicate temporary unavailability of system resources required to complete a requested…
system definitionThe identification of the boundaries of a system to establish a firm basis for any interconnection with other systems [CESG].
system documentationThe collection of documents that describes the requirements, capabilities, limitations, design, operation, and maintenance of a system, such as a…
system failure transferIn the event of a catastrophic failure, the ability to transfer central office trunks or interoffice trunking to predetermined stations to allow incoming…
system follow-upThe study of the effects of a system after it has reached a stabilized state of operational use.