For a basic rate access in an ISDN environment, the interfacing specifications covering pre-ISDN standards (e.g., EIA-232C).

Abbreviation for radio control, radio service.

1. Remote Access,
2. Radiocommunication Assemblies.

Within a building, an enclosure, i.e., channel, used to contain and protect wires, cables, or bus bars.

Resource and Admission Control Functions

A frame upon which one or more units of equipment are mounted.
Note: DOD racks are always vertical.

See radar beacon.

Resource and Admission Control Subsystem

Acronym for radiation absorbed dose. The basic unit of measure for expressing absorbed radiant energy per unit mass of material.
Note 1: A rad corresponds to an absorption of
0. 01 J/kg, i.e., 100 ergs/g.
Note 2: The absorbed radiant energy heats, ionizes, and/or destroys the material upon which it is incident.

Abbreviation for radian(s).

1. Acronym for radio detection and ranging.
1. A radio detection system that transmits short bursts (pulses) of rf energy and detects their echoes from objects (targets) such as aircraft or ships.
Note: The round-trip propagation time for the echo return may be used to determine the target's range (distance from the radar's antenna). If the transmitting antenna has a… (Read More →)

1. A transmitter-receiver associated with a fixed navigational mark which, when triggered by a radar, automatically returns a distinctive signal which can appear on the display of the triggering radar, providing range, bearing and identification information. [NTIA] [RR]
2. A receiver-transmitter combination which sends out a coded signal when triggered by the proper type of pulse, enabling determination of range… (Read More →)

The range that corresponds to the situation in which a radar transmitter is on and hence the receiver must be off, so that the radar transmitted signal does not saturate, i.e., does not blind, its own receiver.
Note: Radar blind ranges occur because there is a time interval between transmitted pulses that corresponds to the time required for a pulse… (Read More →)

The magnitude of the radial component of velocity of an object, i.e., a target, relative to a radar site, that cannot be measured by the radar unit.
Note: Radar blind speeds occur because of the relationship between the transmitted pulse repetition rate (PRR) and the received pulse-repetition rate. The Doppler pulse repetition rate is the difference between the transmitted and… (Read More →)

An expression of the extent to which an object, i.e., a target, reflects radar pulses, usually with respect to their point of origin.
Note: The radar cross section of an aircraft can vary by a factor of over 100, depending on the aspect angle of the aircraft to the radar transmitter. Radar reflection off the nose of the aircraft usually… (Read More →)

Intelligence derived from data collected by radar. [JP 1-02]

The time required for a radar pulse to travel 1 mile (~
1. 6 km) to an object, i.e., to a target; reflect; and return to the receiver.
Note: A radar statute mile is approximately
1
0. 8 s (microseconds); a radar nautical mile is approximately
1
2. 4 s. The time for any other radar unit distance is readily… (Read More →)

The volume of space that is occupied by a radar pulse and that is determined by the pulse duration and the horizontal and vertical beamwidths of the transmitting radar.
Note: The radar cannot distinguish between two separate objects that lie within the same resolution cell. The radar resolution cell depth (RCD) remains constant regardless of the distance from the transmitting… (Read More →)

1. The detailed waveform of a detected radar echo.
Note: Radar signatures may be used to identify or distinguish among objects, i.e., targets, such as aircraft, decoys, missiles with warheads, and chaff. [From Weik '89]
2. The detailed characteristics of a radar transmission.
Note: Radar signatures based upon emission analysis may be used to identify or distinguish among specific radar… (Read More →)

An equation that expresses the radar horizon range (RHR), given by where RHRs is the radar horizon range in statute miles, h is the antenna height in feet, and a is the object critical altitude, i.e., the target altitude in feet, below which the radar cannot illuminate the object.
Note: The RHR is also given by where RHRk is the… (Read More →)

Acronym for electromagnetic radiation hazards.

A unit of plane angle measure equal to the angle subtended at the center of a circle by an arc equal in length to the radius of the circle.
Note: One radian is equal to 360°/2, which is approximately 57° 17'
4
4. 6".

Radiant power, in a given direction, per unit solid angle per unit of projected area of the source, as viewed from the given direction.
Note: Radiance is usually expressed in watts per steradian per square meter.

Radiant power emitted into a full sphere, i.e., 4 sr (steradians), by a unit area of a source, expressed in watts per square meter. Synonym radiant exitance.

Energy in the form of electromagnetic waves.
Note 1: Radiant energy may be calculated by integrating radiant power with respect to time.
Note 2: Radiant energy is usually expressed in joules.

Synonym radiant emittance.

Deprecated synonym for radiant power.

Radiant power per unit solid angle, usually expressed in watts per steradian.

The rate of flow of electromagnetic energy, i.e., radiant energy.
Note 1: Radiant power is usually expressed in watts, i.e., joules per second.
Note 2: The modifier is often dropped and "power" is used to mean "radiant power". Deprecated synonyms flux, radiant flux.

1. In communication, the emission of energy in the form of electromagnetic waves.
2. The outward flow of energy from any source in the form of radio waves. [NTIA] [RR]

In fiber optics, half the vertex angle of the cone of light emitted at the exit face of an optical fiber.
Note: The cone boundary is usually defined (a) by the angle at which the far-field irradiance has decreased to a specified fraction of its maximum value or (b) as the cone within which there is a specified fraction of… (Read More →)

At a given frequency, the ratio of the power radiated to the total power supplied to the radiator.

Synonym far-field region.

For an optical fiber, an unbound mode.
Note: In an optical fiber, a radiation mode is one having fields that are transversely oscillatory everywhere external to the waveguide, and which exists even at the limit of zero wavelength. Specifically, a radiation mode is one for which where is the imaginary part (phase term) of the axial propagation constant, integer is… (Read More →)

1. The variation of the field intensity of an antenna as an angular function with respect to the axis.
Note: A radiation pattern is usually represented graphically for the far-field conditions in either horizontal or vertical plane.
2. In fiber optics, the relative power distribution at the output of a fiber or active device as a function of position or… (Read More →)

The resistance that, if inserted in place of an antenna, would consume the same amount of power that is radiated by the antenna.

The diversion of radiation (thermal, electromagnetic, or nuclear) from its original path as a result of interaction or collisions with atoms, molecules, or larger particles in the atmosphere or other media between the source of radiation (e.g., a nuclear explosion) and a point some distance away. As a result of scattering, radiation (especially gamma rays and neutrons) will be received… (Read More →)

Measures to defend against TEMPEST attacks [CESG].

An optical fiber made with core and cladding materials that recover, within a specified period of time, a specified percentage of their intrinsic transparency after darkening from exposure to a radiation pulse.

Acronym for radar intelligence.

1. Telecommunication by modulation and radiation of electromagnetic waves.
2. A transmitter, receiver, or transceiver used for communication via electromagnetic waves.
3. A general term applied to the use of radio waves. [NTIA] [RR]

A controller that supports the wireless mobility management and wireless access call control functions. It serves one or more subtending radio port controllers and may be associated with one or more PCS switching centers. [After T
1. Rpt34-1994]

Radionavigation equipment, on board an aircraft or spacecraft, used to determine the height of the aircraft or the spacecraft above the Earth's surface or another surface. [NTIA] [RR]

The combining of wire circuits with radio facilities. [JP 1-02]

See baseband.

A radiation pattern from a directional antenna, such that the energy of the transmitted electromagnetic wave is confined to a small angle in at least one dimension.

An assigned band of frequencies sufficient for radio communication.
Note 1: The bandwidth of a radio channel depends upon the type of transmission and the frequency tolerance.
Note 2: A channel is usually assigned for a specified radio service to be provided by a specified transmitter.

An encryption treatment applied to signaling or user data, which treatment is intended to prevent an unauthorized detector of the data from extracting information. [T
1. Rpt34-1994]

A telecommunications common carrier that provides radio communications services but is not engaged in the business of providing landline local exchange telephone service. [47CFR]

The remote control of an apparatus by signals conveyed by electromagnetic waves.
Note: Radio control may be used to control the movement of an aircraft, vehicle, missile, or other mobile unit, either manned or unmanned, from a radio station on the ground or in another mobile unit. [From Weik '89]

The detection of the presence of an object by radiolocation without precise determination of its position. [JP 1-02]

See radar.

A radiodetermination station using radio direction-finding. [NTIA] [RR]

Radiodetermination using the reception of radio waves for the purpose of determining the direction of a station or object. [NTIA] [RR]

As defined in Federal Information Management Regulations, any equipment or interconnected system or subsystem of equipment (both transmission and reception) that is used to communicate over a distance by modulating and radiating electromagnetic waves in space without artificial guide. This does not include such items as microwave, satellite, or cellular telephone equipment.

The bearer/signaling connection between the radio port intermediary and the radio port controller. [T
1. Rpt34-1994]

See flutter.

Synonym field strength.

1. The locating of a radio transmitter by bearings taken from two or more direction finding stations, the site of the transmitter being at the point of intersection. [JP 1-02]
2. The location of a ship or aircraft by determining the direction of radio signals coming to the ship or aircraft from two or more sending stations, the locations of… (Read More →)

See RF.

See frequency assignment.

Synonym frequency assignment.

Typically this term is used with RFID tags, where RFID tag data contains product identification.

Synonym electromagnetic interference.

The locus of points at which direct rays from an antenna are tangential to the surface of the Earth.
Note: If the Earth were a perfect sphere and there were no atmospheric anomalies, the radio horizon would be a circle. In practice, the distance to the radio horizon is affected by the height of the transmitting antenna, the height of… (Read More →)

1. The distance at which a direct radio wave can reach a receiving antenna of given height from a transmitting antenna of given height.
Note: The radio horizon range in nautical miles, R, is given by the relation R =
1. 23(ht1/2 + hr1/2), where ht and hr are the heights of the transmitting and receiving antennas in feet. The… (Read More →)

The common boundary between a mobile station and the radio equipment in the network, which is the boundary defined by functional characteristics, physical interconnection characteristics, signal characteristics, and other characteristics as appropriate.

1. An organization of radio stations that is capable of direct communication on a common frequency.
2. An organization of radio stations that broadcast common programming, not necessarily simultaneously, at different frequencies from different locations.

The use of a pocket-size radio receiver capable of alerting its wearer that there is a phone call, either from a displayed phone number or to a predesignated number.
Note: Radio paging may be considered a subset of paging. Synonym beeping.

A light-weight, pocket-size portable radio terminal (or "personal terminal") providing the capability for the user to be either stationary or in motion while accessing and using telecommunication services. [T1.244-1995] Synonym [loosely] brick.

A unit that supports transmission of signals over the air interface. [After T
1. Rpt34-1994]

A controller that provides an interface between one or more subtending radio port intermediaries and a PCS switching center, and supports air interface independent radio frequency transmission and reception functions. [After T
1. Rpt34-1994]

1. The distance from a transmitter at which the signal strength remains above the minimum usable level for a particular antenna and receiver combination.
2. A radio aid to air navigation that creates an infinite number of paths in space throughout a given sector or azimuth angle by various methods of transmission and reception of electromagnetic waves. [From Weik '89]

A radionavigation land station in the aeronautical radionavigation service providing radial equisignal zones. (In certain instances a radio range station may be placed on board a ship. ) [NTIA]

See identification, friend or foe.

As used in legal documents, the latest (i.e., as of the document date) ITU Radio Regulations to which the United States is a party.

A permanent organization of the International Telecommunication Union (ITU) that implements frequency assignment policy and maintains the Master International Frequency Register (MIFR).
Note: Formerly International Frequency Registration Board (IFRB).

1. The reception and retransmission by a radio station of signals that are received either from another radio station or from a wire, fiber optic, microwave, coaxial cable, or other link of an integrated land line and radio communications system component.
2. A terrestrial point-to-point communications system, such as a microwave-relay communications system or a satellite communications system.
Note: The… (Read More →)

A point-to-point radio transmission system in which signals are received, conditioned, and retransmitted by one or more intermediate radio stations.

The transmission of telegraphic codes by means of radio. [JP 1-02]

The transmission of speech by means of modulated radio waves. [JP 1-02]

A teletypewriter employed in a communication system using radio circuits.
Note: Such systems are spoken of as RATT systems.

A device or functionality that terminates radio transmissions, performs radio channel management, provides rate adaptation between the radio channel and the user channel and provides mobility management functions. [T1.702-1995] [Tl.705]

Synonym area broadcast shift.

An electromagnetic wave of a frequency arbitrarily lower than 3000 GHz. Synonym Hertzian wave.

A diagram that shows the area within which a radio station is broadcasting an effective signal strength in relation to a given standard.
Note: An example of a radio-coverage diagram is a polar plot, in each direction from the antenna, of the distance from the antenna at which the signal strength is equal to a specified value, i.e., it is… (Read More →)

See radio and wire integration.

A station in the radionavigation service the emissions of which are intended to enable a mobile station to determine its bearing or direction in relation to the radiobeacon station. [NTIA] [RR]

Telecommunication by means of radio waves. [NTIA] [RR] [47CFR]

A service as defined in this Section [of the Radio Regulations] involving the transmission, emission and/or reception of radio waves for specific telecommunication purposes. In these regulations, unless otherwise stated, any radiocommunication service relates to terrestrial radiocommunication. [NTIA] [RR]

The determination of the position, velocity and/or other characteristics of an object, or the obtaining of information relating to these parameters, by means of the propagation properties of radio waves. [NTIA] [RR] [47CFR]

A station in the radiodetermination service. [NTIA] [RR]

A radiocommunication service for the purpose of radiodetermination involving the use of one or more space stations. This service may also include feeder links necessary for its own operation. [NTIA] [RR] [47CFR]

Radiodetermination used for purposes other than those of radionavigation. [NTIA] [RR] [47CFR]

A station in the radiolocation service not intended to be used while in motion. [NTIA] [RR] [47CFR]

1. A station in the radiolocation service intended to be used while in motion or during halts at unspecified points. [NTIA] [RR]
2. A station intended to be used while in motion or during halts at unspecified points. [47CFR]

A radiodetermination service for the purpose of radiolocation. [NTIA] [RR]

Synonym monitoring.

The science of radiation measurement. See Table of Radiometric Terms. TABLE OF RADIOMETRIC TERMS Term Symbol Quantity Unit radiant energy Q energy joule (J) radiant power Synonym optical power power watt (W) irradiance E power incident per unit area (irrespective of angle) W•m-2 spectral irradiance E irradiance per unit wavelength interval at a given wavelength W•m-2•nm-1 radiant emittance Synonym radiant… (Read More →)

1. Radiolocation intended for the determination of position or direction or for obstruction warning in navigation. [JP 1-02]
2. Radiodetermination used for the purposes of navigation, including obstruction warning. [NTIA] [RR] [47CFR]

A station in the radionavigation service not intended to be used while in motion. [NTIA] [RR]

A station in the radionavigation service intended to be used while in motion or during halts at unspecified points. [NTIA] [RR]

A radiodetermination-satellite service used for the purpose of radionavigation. This service may also include feeder links necessary for its operation. [NTIA] [RR]

An automatic radio transmitter in the meteorological aids service usually carried on an aircraft, free balloon, kite, or parachute, and which transmits meteorological data. [NTIA] [RR]

A telegram, originating in or intended for a mobile station or a mobile Earth station transmitted on all or part of its route over the radiocommunication channels of the mobile service or of the mobile-satellite service. [NTIA] [RR]

Telemetry by means of radio waves. [NTIA] [RR]

A telephone call, originating in or intended for a mobile station or a mobile Earth station, transmitted on all or part of its route over the radiocommunication channels of the mobile service or of the mobile-satellite service. [NTIA] [RR]

An international distress and calling frequency for mobile radiotelephone stations, survival craft, and emergency position-indicating radio beacons.
Note: An example of a radiotelephone distress frequency is 2180 kHz. [From Weik '89]

A telex call, originating in or intended for a mobile station or a mobile Earth station, transmitted on all or part of its route over the radiocommunication channels of the mobile service or the mobile-satellite service. [NTIA] [RR]

Remote Authentication Dial In User Service

Redundant Array of Independent Disks

[A] set of publications that interpret Orange Book requirements for trusted systems. [INFOSEC-99]

Acronym for random access memory.

Synonym fiber amplifier.

The generation of many different wavelengths of light from a nominally single-wavelength source (a) by means of lasing action and interaction with molecules, thereby creating many different excited molecular energy levels that will produce photons of various energy levels, i.e., various wavelengths, when transitions to lower excited states occur and (b) by the beating together of two frequencies, thus inducing… (Read More →)

A communications technique in which radio users share one wide frequency band instead of each user's being assigned a narrow band.

A read/write, nonsequential-access memory used for the storage of instructions and data.
Note 1: RAM access time is essentially the same for all storage locations.
Note 2: RAM is characterized by a shorter access time than disk or tape storage.
Note 3: RAM is usually volatile.

Data that are (a) unpredictable and have no discernable pattern, or (b) satisfy certain mathematical criteria for statistical randomness.

Errors distributed over the signal in time so that they can be considered statistically independent from each other. [T1.226-1992]

Noise consisting of a large number of transient disturbances with a statistically random time distribution.
Note: Thermal noise is an example of random noise.

1. A number selected from a known set of numbers in such a way that each number in the set has the same probability of occurrence.
2. A number obtained by chance.
3. One of a sequence of numbers considered appropriate for satisfying certain statistical tests or believed to be free from conditions that might bias the result of a… (Read More →)

1. A device used to invert the sense of pseudorandomly selected bits of a bit stream to avoid long sequences of bits of the same sense.
Note: The same selection pattern must be used on the receive terminal in order to restore the original bit stream.
2. [An] analog or digital source of unpredictable, unbiased, and usually independent bits. Randomizers… (Read More →)

See radio range.

The measurement of the distance to a remote object (target), from a known observation or reference point.
Note: Ranging may be accomplished by geometric means, e.g., triangulation, or by the measurement of the transit time of an electromagnetic or acoustic signal. Ranging has application to navigation and cartography.

A predetermined pattern of scanning lines within a display space.
Note: An example of a raster is the pattern followed by an electron beam scanning the screen of a television camera or receiver.

The total number of raster scanning lines within a display space. [From Weik '89]

In display systems, the number of scanning lines per unit distance perpendicular to the scanning direction. [From Weik '89]

Synonym [loosely] bitmapped graphics.

Scanning in which the motion of the scanning spot follows a raster.

These measurements can be used with the tariffs in the message rating processes. Rate Center is used for numbering resource applications and reports to associate telephone numbers with a geographic area, as defined by the relevant regulatory agency.

That power available at a specified output of a device under specified conditions of operation.
Note: Rated output power may be further described; e.g., maximum rated output power, average rated output power.

A measure for the assurance that may be held in a Target of Evaluation, consisting of a reference to its security target, an evaluation level established by assessment of the correctness of its implementation and consideration of its effectiveness in the context of actual or proposed operational use, and a confirmed rating of the minimum strength of its security mechanisms… (Read More →)

Synonym maximal-ratio combiner.

A geometric representation of a lightwave by a line normal to the electromagnetic wavefront; i.e., in the direction of propagation of the wave. [FAA]

Synonym geometric optics.

A mathematical statement, usually applied to frequency distributions of random variables, for the case in which two orthogonal variables are independent and normally distributed with unit variance.

In electromagnetic wave propagation, phase-interference fading caused by multipath, and which may be approximated by the Rayleigh distribution.

Of an electromagnetic wave propagating in a material medium, scattering caused by refractive-index inhomogeneities that are small compared to the wavelength.
Note 1: Rayleigh scattering losses vary as the reciprocal of the fourth power of the wavelength.
Note 2: Ionospheric scattering is caused partly by Rayleigh scattering.

Acronym for Regional Bell Operating Company.

Abbreviation for radio common carrier.

Return Data Channel

Abbreviation for radio direction-finding.

1. [A] fundamental operation in an information system (IS) that results only in the flow of information from an object to a subject. [INFOSEC-99]
2. A fundamental operation that results only in the flow of information from an object to a subject [POSIX.6].
3. A fundamental operation that results only in the flow of information from an object to a… (Read More →)

1. In computer or data processing technology, the privilege (or capability) of reading electronically the information in a file or data base, without the privilege (or capability) to modify it. Synonym read-only access.
2. [In INFOSEC,] permission to read information in an information system (IS). [INFOSEC-99]
3. Permission to read information [TCSEC].

A magnetic head capable of reading only.

See read access.

1. A memory in which data, under normal conditions, can only be read. Synonym nonerasable storage.2A storage area in which the contents can be read but not altered during normal computer processing [TCSEC].

A storage device in which the contents cannot be modified, except by a particular user, or when operating under particular conditions, e.g., a storage device in which writing is prevented by a lockout. Synonym fixed storage.

Synonym read/write slot.

An opening in the jacket of a diskette to allow access to the read/write heads. Synonym read/write opening.

The acquisition or interpretation of data from a storage device, from a data medium, or from another source.

1. A call-control signal that is transmitted by the data circuit-terminating equipment (DCE) to the data terminal equipment (DTE) to indicate that the connection is available for data transfer between both DTEs.
2. A signal that (a) is sent in the backward direction in the interexchange data channel, to indicate that all the succeeding exchanges involved in the connection have… (Read More →)

See effective power.

1. The actual time during which a physical process occurs.
2. Pertaining to the performance of a computation during the actual time that the related physical process occurs, in order that results of the computation can be used in guiding the physical process.

A set of on-demand procedures based on which the communication can be started in relatively short time (i.e., on the order of few seconds) after the request is made. [T1.606-1990]

RTT is text transmitted character-by-character in real time with the intent of being displayed immediately to the receiving person(s).

RTT is text transmitted character-by-character in real time with the intent of being displayed immediately to the receiving person(s).

The purpose of this element is to ingest what could be a multitude of content, to encrypt that content in real time using keys that are provided by the Key Management element, and to output a stream of that encrypted real-time content.

[In INFOSEC, the] immediate response to a penetration attempt that is detected and diagnosed in time to prevent access. [INFOSEC-99]

A high degree of confidence by an individual, entity, or application that received data should be treated as valid and unaltered. [After X9.30-1]

A test to determine whether a value conforms to specified criteria.
Note: A reasonableness check can be used to eliminate questionable data points from subsequent processing. Synonym wild-point detection.

An action that re-establishes the communication with a participant of the conference. [T1.647-1995]

See receive objective loudness rating.

The ratio in dB of the voltage entering a loop and telephone to the sound pressure produced by the telephone's receiver. [After T1.255-1997]

Pertaining to a device or a mode of operation capable of receiving messages, but not of transmitting messages.

The time interval between (a) the instant of keying off the local transmitter to stop transmitting and (b) the instant the local receiver output has increased to 90% of its steady-state value in response to an rf signal from a distant transmitter.
Note 1: The rf signal from the distant transmitter must exist at the local receiver input prior to,… (Read More →)

1. The calculated or measured noise power, within the bandwidth being used, at the receive end of a circuit, channel, link, or system.
2. The absolute power of the noise measured or calculated at a receive point.
Note: The related bandwidth and the noise weighting must also be specified.
3. The value of noise power, from all sources, measured at… (Read More →)

The signal level at a receiver input terminal.
Note 1: The signal bandwidth and the established reference level must be specified.
Note 2: The RSL is usually expressed in dB with respect to 1 mW, i.e., 0 dBm.

The sink or terminator of any signal on a transmission medium. [T1.408-1990]

The time interval from (a) the instant a step rf signal, at a level equal to the receiver threshold of sensitivity, is applied to the receiver input to (b) the instant the receiver output amplitude reaches 90% of its steady-state value.
Note: If a squelch circuit is operating, the receiver attack-time delay includes the time for the receiver to break… (Read More →)

Synonym lockout.

The maximum acceptable value of the received average optical power consistent with a bit error ratio (BER) of 1 x 10-10 or better. [T1.646-1995]

The time interval from removal of rf energy at the receiver input until the receiver output is squelched.

The minimum value of average received power to achieve a 1 x 10-10 bit error ratio. It includes power penalties caused by use of a transmitter under standard operating conditions with worst-case values of extinction ratio, pulse rise and fall times, optical return loss, receiver connector degradations, and measurement tolerances. [T1.646-1995]

The switch or network to which a subscriber's directory number has been ported. [T1.711-1999]

Reclamation refers to the process by which service providers are required to return numbering resources to the NANPA (FCC 00-104, §
5
2. 15 (i) (1))

Any operating agency, as defined in the ITU Convention (Geneva, 1992), which operates a public correspondence or broadcasting service and upon which the obligations provided for in Article 6 of the ITU Constitution are imposed by the Member in whose territory the head office of the agency is situated, or by the Member which has authorized this operating agency to… (Read More →)

Synonym exalted-carrier reception.

An analog sample generated at the output of a decoder when a specified character signal is applied at its input.
Note: The amplitude of the reconstructed sample is proportional to the value of the corresponding encoded sample.

In ADPCM (adaptive differential pulse code modulation), the sum of the signal estimate from adaptive prediction and the quantized difference signal from inverse adaptive quantization. [T1.310-1991]

1. A set of data treated as a unit.
2. To write data on a medium, such as magnetic tape, magnetic disk, or optical disk.
3. In PCS (personal communications services), a string of bytes within an extended frame (EF) handled as a single entity. [After T1.707-1998]

1. A telecommunications process that produces an electronic message that is transmitted, received, stored or archived, and may be retrieved.
2. A telecommunications process, that produces a hard copy record of the transmission, such as a teletypewriter printout or a facsimile printout.
3. Any transmission of intelligence which is reduced to visual record form at the point of reception. [47CFR]

All forms (e.g., narrative, graphic, data, computer memory) of information registered in either temporary or permanent form so that it can be retrieved, reproduced, or preserved. [JP1]

1. The physical medium on which information is stored in recoverable form.
2. In facsimile transmission, the physical medium on which the recorder forms an image of the object, i.e., creates the recorded copy.
Note: The record medium and the record sheet may be identical. Synonym record sheet.

The number that identifies a record within an extended frame (EF). [After T1.707-1998]

The pointer which is used to address one record in an extended frame (EF). [After T1.707-1998]

Synonym record medium.

1. Traffic that is recorded, in permanent or quasipermanent form, by the originator, the addressee, or both.
2. Traffic that is permanently or semipermanently recorded in response to administrative procedures or public law.

A half-second burst of 1400 Hz applied to a telephone line every 15 seconds to indicate to the called party that the calling party is recording the conversation.
Note: The recorder warning tone is required by law to be generated as an integral part of any recording device used for the purpose and is required to be not under the… (Read More →)

Synonym bit density.

In a facsimile recorder, the spot that is used to generate the recorded copy on the record medium.

In a database management system, the procedures and capabilities available for reconstruction of the contents of a database to a state that prevailed before the detection of processing errors and before the occurrence of a hardware or software failure that resulted in the destruction of some or all of the stored data.

1. [The] action[s] necessary to restore data files of an information system (IS) and computational capability after a system failure. [INFOSEC-99].
2. In data communications, a process whereby a data station attempts to resolve conflicting or erroneous conditions arising during the transfer of data.

[The] designation applied to information systems, and associated areas, circuits, components, and equipment in which national security information is being processed. [INFOSEC-99]

1. [A] Telecommunications or automated information system signal that would divulge classified information if recovered and analyzed. [NIS]
2. In cryptographic systems, a signal containing classified information that has NOT been encrypted.
3. Any electronic emission (e.g., plain text, key, key stream, subkey stream, initial fill, or control signal) that would divulge national security information if recovered. [INFOSEC-99]

[The] Separation of electrical and electronic circuits, components, equipment, and systems that handle national security information (RED), in electrical form, from those that handle non-national security information (BLACK) in the same form. [INFOSEC-99]

A set of digits and related indicators (type of number, numbering plan identification, screening indicator, presentation indicator) that provide numbering information related to the redirecting party. [T1.625-1993]

A system profile construction method of starting at a base platform and adding new services by allowing a service component to ask the base platform to redirect all requests for that type of service to the service component [POSIX.0].

A single-sideband emission in which the degree of carrier suppression enables the carrier to be reconstituted and to be used for demodulation. [NTIA] [RR]

A form of amplitude-modulation in which the carrier is transmitted at a controlled level below that which is required for demodulation, but at a level sufficient to serve as a frequency reference.

1. In the transmission of data, the excess of transmitted message symbols over that required to convey the essential information in a noise-free circuit.
Note: Redundancy may be introduced intentionally (as in the case of error detection or correction codes) or inadvertently (such as by oversampling a band-limited signal, inefficient formats, etc. ).
2. In a communication system, surplus capability… (Read More →)

1. A method of verifying that any redundant hardware or software in a communication system is in an operational condition.
2. A check that uses one or more extra binary digits or characters attached to data for the detection of errors.

A code using more signal elements than necessary to represent the intrinsic information.
Note: The redundancy may be used for error-control purposes.

An antenna that may be real, virtual, or theoretical, and has a radiation pattern that can be used as a basis of comparison with other antenna radiation patterns.
Note: Examples of reference antennas are unit dipoles, half-wave dipoles, and isotropic, i.e., omnidirectional antennas. [From Weik '89]

[In television,] The level corresponding to the specified maximum excursion of the luminance signal in the black direction. [47CFR]

A hypothetical circuit of specified equivalent length and configuration, and having a defined transmission characteristic or characteristics, used primarily as a reference for measuring the performance of other, i.e., real, circuits or as a guide for planning and engineering of circuits and networks.
Note: Normally, several types of reference circuits are defined, with different configurations, because communications are required over… (Read More →)

1. A clock with which another clock is compared.
2. A clock, usually of high stability and accuracy, used to govern a network of mutually synchronized clocks of lower stability.
Note: The failure of a reference clock does not necessarily cause loss of synchronism.

The geometric representation of colors in three-dimensional space. [CIE 845-03-25]
Note: There are three reference spaces recognized by ISO 8613: CMYK color space; CIELuv color space, and R,G,B color space. [After SMPTE]

In ISDN, a combination and arrangement of functional groups and reference points that reflect possible network topology.

an information transfer between two server application processes acting cooperatively on instructions from a third application process.

1. A standard fixed frequency from which operational frequencies may be derived or with which they may be compared.
Note: The reference frequency may be used to specify an assigned frequency or fix a characteristic or carrier frequency.
2. A frequency having a fixed and specific position with respect to the assigned frequency. The displacement of this frequency with respect… (Read More →)

A set of conventions and concepts, mutually agreed upon between the information system user and provider communities [POSIX.0].

1. A video display that is used to view a video signal to determine its image quality.
2. [An] Access control concept referring to an abstract machine that mediates all accesses to objects by subjects. [INFOSEC-99]
3. In security, the concept of an abstract machine that enforces target-of-evaluation (TOE) access control policies and security processes. [After CC-99]

1. An access control concept that refers to monitoring of all accesses to objects by subjects [CESG].
2. An access control concept that refers to an abstract machine that mediates all accesses to objects by subjects [TCSEC].

An access control concept utilizing an abstract machine to mediate all access to objects by subjects.

The magnitude of circuit noise chosen as a reference for measurement.
Note: Many different levels with a number of different weightings are in current use, and care must be taken to ensure that the proper parameters are stated. See dBa, dBa0, dBm, dBm0, dBrn, dBrnC, dBrnC0, dBx.

In ISDN, a logical point between two, nonoverlapping functional groups.
Note: When equipment is placed at a reference point, that reference point is designated an interface.

In optical-fiber technology, that surface of an optical fiber that is used to contact the transverse-alignment elements of a component such as a connector or mechanical splice.
Note: For telecommunications-grade fibers, the reference surface is the outer surface of the cladding. For plastic-clad silica (PCS) fibers, which have a strippable polymer cladding (not to be confused with the polymer overcoat… (Read More →)

A group of related reference circuits.

See relative transmission level, transmission level point.

[The] Portion of a trusted computing base whose normal function is to control access between subjects and objects and whose correct operation is essential to the protection of data in the system. [INFOSEC-99]

The artificially generated time history of an earthquake, derived from the histories of many actual earthquake accelerometers. The reference waveform is to be used for test performance. [T1.329-1995]
Note: The reference waveform is useful in CIP (communications infrastructure protection) efforts.

[In television,] The level corresponding to the specified maximum excursion of the luminance signal in the white direction. [47CFR]

The ratio of reflected power to incident power, generally expressed in dB or percent.

Synonym Gray code.

In the ionosphere, a layer that has a free-electron density sufficient to reflect radio waves.
Note 1: The principal reflecting layers are the E, F1, and F2 layers in the daylight hemisphere.
Note 2: A critical frequency is associated with the reflection by each layer.

See reflection loss.

The abrupt change in direction of a wave front at an interface between two dissimilar media so that the wave front returns into the medium from which it originated.
Note 1: Reflection may be specular (i.e., mirror-like) or diffuse (i.e., not retaining the image, only the energy) according to the nature of the interface.
Note 2: Depending on the nature… (Read More →)

1. The ratio of the amplitude of the reflected wave and the amplitude of the incident wave.
2. At a discontinuity in a transmission line, the complex ratio of the electric field strength of the reflected wave to that of the incident wave.
Note 1: The reflection coefficient may also be established using other field or circuit quantities.
Note 2:… (Read More →)

1. At a discontinuity or impedance mismatch, e.g., in a transmission line, the ratio of the incident power to the reflected power.
Note 1: Reflection loss is usually expressed in dB.
Note 2: The reflection loss, Lr, is given by where Z1 and Z2 are the respective impedances, and the vertical bars designate absolute magnitude.
2. In an optical fiber,… (Read More →)

An antenna, such as a billboard antenna, in which the driven elements are situated at a predetermined distance from a surface designed to reflect the signal in a desired direction.
Note: Reflective array antennas (a) usually have many driven elements working in conjunction with an electrically large reflecting surface to produce a unidirectional beam, (b) may be used to increase… (Read More →)

The reflectance at the surface of a material so thick that the reflectance does not change with increasing thickness, i.e., the intrinsic reflectance of the surface, irrespective of other parameters such as the reflectance of the rear surface.
Note: The term "reflectivity" is no longer in common use. See reflectance.

1. In an rf antenna, one or more conducting elements or surfaces that reflect incident radiant energy.
Note: A reflector may consist of a large surface, as in a dish antenna, or a linear element, as in a Yagi antenna.
2. See mail reflector.

1. A ray that undergoes a change of velocity, or in the general case, both velocity and direction, as a result of interaction with the material medium in which it travels.
2. In an optical fiber, a ray that is refracted from the core into the cladding. Specifically a ray having direction such that where r is the radial distance… (Read More →)

Retardation, and--in the general case--redirection, of a wavefront passing through (a) a boundary between two dissimilar media or (b) a medium having a refractive index that is a continuous function of position, e.g., a graded-index optical fiber.
Note: For two media of different refractive indices, the angle of refraction is closely approximated by Snell's Law.

Synonym refractive index profile.

Of a medium, the ratio of the velocity of propagation of an electromagnetic wave in vacuum to its velocity in the medium. Synonym index of refraction.
Note: When the Greek character eta is unavailable, the letter n is used to represent the refractive index.

In an optical fiber, a measure of the relative difference in refractive index of the core and cladding.
Note: Refractive index contrast, , is given by = (n12- n 22)/(2n12), where n1 is the maximum refractive index in the core and n2 is the refractive index of the homogeneous cladding.

Of the cross section of an optical fiber, the description, i.e., plot, of the value of the refractive index as a function of distance from the fiber axis along a diameter. Synonyms index profile, refraction profile.

The time interval between the instant at which a valid frame-alignment signal is available at the receiving data terminal equipment and the instant at which frame alignment is established.
Note: The reframing time includes the time required for replicated verification of the validity of the frame-alignment signal. Synonym frame-alignment recovery time.

To reproduce, repeatedly, a display image on a display surface, so that the image remains visible.

Signaling packets that are transmitted on a periodic basis across a permanent virtual circuit in the direction of transmission from the channelized side to the packetized side. This allows the originating endpoint to update the knowledge of the terminating endpoint regarding the signaling information on the incoming channel and the status of the permanent virtual circuit status. [T1.312-1991]

1. In a regenerative repeater, the process by which digital signals are amplified, reshaped, retimed, and retransmitted. Synonym positive feedback.
2. In a storage or display device, the restoration of stored or displayed data that have deteriorated.
Note: For example, conventional cathode-ray tube displays must be continually regenerated for the data to remain displayed.
3. In computer graphics, the sequence… (Read More →)

Feedback in which the portion of the output signal that is returned to the input has a component that is in phase with the input signal.

A repeater, designed for digital transmission, in which digital signals are amplified, reshaped, retimed, and retransmitted. Synonym regenerator.

1. Synonym regenerative repeater.
2. A device that reconstructs and retransmits a received pulse train. [T1.403-1989]

Historically, one of the seven holding companies formed by divestiture by the American Telephone and Telegraph Company of its local Bell System operating companies, and to which one or more of the Bell System local telephone companies were assigned.

See office classification.

1. A device, accessible to one or more input circuits, that accepts and stores data.
Note: A register is usually used only as a device for temporary storage of data.
2. A temporary-memory device used to receive, hold, and transfer data (usually a computer word) to be operated upon by a processing unit.
Note: Computers typically contain a variety of… (Read More →)

Any of the series of jacks, described in the Code of Federal Regulations, Title 47, part 68, used to provide interface to the public telephone network.

1. The accurate positioning of, or the degree of accuracy in the positioning of, an entity relative to (a) another entity, or (b) an independent frame of reference.
Note: For example, in color graphics applications involving the superposition of several colored rasters, such as in a CRT display, good registration (usually termed "convergence" in this context) is of paramount importance… (Read More →)

An application process that receives an RRP (registration request protocol), message from the registration manager signaling it to start automatic registration. The result is that the RNE's (remote network element's) DUA (directory user agent) adds the NE (network element) system administrative information (e.g., name, make, location, etc. ) into the DIB (directory information base) via the "add Entry" operation of… (Read More →)

In networking, an organization that performs registration for information objects and devices. [After 2382-pt.35]

An application process responsible for contacting the registration agent using the RRP (registration request protocol) to start automatic registration of a newly discovered NE (network element) into the DIB (directory information base). The RM provides the RA (registration agent) with the appropriate DSA (directory system agent) address. [T1.245-1997]

In networking, the procedure for performing registration or for amending or deleting existing registrations. [2382-pt.35]

See FCC Registration Program.

The changing of one or more keys that are used for either COMSEC or TRANSEC functions.

A database that consists of data in simple tables (i.e., rows and columns) and that has no system dependencies (e.g., pointers to other data).

In computer and data processing programming, an address that is expressed as a difference in relation to a base address. [After Weik '96]

The ratio of an absolute error to the true, specified, or theoretically correct value of the quantity that is in error.

See spectral width.

The ratio of the signal power, at a given point in a transmission system, to a reference signal power.
Note: The ratio is usually determined by applying a standard test tone at zero transmission level point (or applying adjusted test tone power at any other point) and measuring the gain or loss to the location of interest. A distinction should… (Read More →)

1. To retransmit a received message from one station to another station.
2. An electromechanical or semiconductor switch (i.e., solid-state relay) in which a current or voltage applied across one port or terminal controls electrical currents or voltages that appear across another terminal or terminals.

An operating configuration in which a circuit is established between two stations via an intermediate relay station. Two links are used simultaneously and the channel connections at the relay station are accomplished completely within the station.

1. An intermediate station that passes information between terminals or other relay stations.
2. A fixed station used for the reception and retransmission of the signals of another station or stations. [47CFR]

The initial destination of a call from a pivot node.
Note: A service or network capability provided at the release node, after determining the call should be connected to a destination node other than itself, may invoke RTP (registration request protocol) to have the new connection established from a pivot node earlier in the call path. After releasing the call… (Read More →)

[A] prefix appended to the short title of U. S. -produced keying material to indicate its foreign releasability. "A" designates material that is releasable to specific allied nations and "U. S. " designates material intended exclusively for U. S. use. [INFOSEC-99]

1. The time interval between (a) the instant that an enabling signal (as in a vogad or echo suppressor) is discontinued, and (b) the instant at which suppression ceases.
2. The time interval between (a) the instant a relay coil is de-energized, and (b) the instant that contact closure ceases (or, depending on the nature of the relay, is established).

A timer that specifies the period of time the network will wait for a release from the user after informing the user of a failure condition such as busy. This timer is on the order of 30 seconds. [T1.620-1991]

Synonym switched loop.

1. The ability of an item to perform a required function under stated conditions for a specified period of time.
2. The probability that a functional unit will perform its required function for a specified interval under stated conditions.
3. The continuous availability of communication services to the general public, and emergency response activities in particular, during normal operating conditions… (Read More →)

See performance reliability.

1. The process of determining whether existing hardware, firmware, or software has achieved a specified level of operational reliability.
2. The process of determining the achieved level of operational reliability of existing hardware, firmware, or software. Synonym reliability evaluation. [From Weik '89]

Synonym reliability assessment.

1. Residual information remaining on storage media after clearing. [INFOSEC-99]
2. The persistence of information on computing or communications media or equipment even following a purge [CESG].
Note: Normally used to refer to residual information which would only be accessible using specialist techniques. Example: magnetic remanence. See also: Object Reuse, Purge.

1. Pertaining to communication with a data processing facility from a remote location or facility through a data link.
2. A PABX service feature that allows a user at a remote location to access by telephone PABX features, such as access to wide area telephone service (WATS) lines.
Note: For remote access, individual authorization codes are usually required.

Data processing in which some input/output functions are performed by devices that are connected to a computer system by means of data communication.

An access line (e.g., for WATS or TWX service) between a subscriber's premises in one toll rate center and a serving central office located in a different toll rate center. [47 CFR Pt.36-A]

In a PVP (packetized voice protocol) node, an indication that the far-end PVP node is experiencing an alarm condition. This occurs because of either the loss of keep-alive signaling packets, or the receipt of signaling packets with the normal/alarm (N/A) bit set to
1. [T1.312-1991]

A signal transmitted in the outgoing direction when a terminal determines that it has lost the incoming signal. RAI is commonly called the yellow alarm signal. For superframe (SF) operation, an RAI is transmitted by setting the bit-2 position of every channel time slot to zero. For extended superframe (ESF) operation, an RAI is transmitted by introducing a priority message… (Read More →)

A feature that enables the UPT user to make a remote Incall registration and a remote OutCall registration to the same terminal address using one single procedure. The effect of a remote AllCall registration is as if remote Incall and remote OutCall registration had been carried out separately. [T1.701-1994]

Submission of batches of data through an input unit that has access to a computer through a data link.

Batch processing in which input-output units have access to a computer through a data link.

Of a computer, its start or restart from a remote location.
Note: A remote boot may be accomplished by a hardware or software trigger.

A service feature that allows calls coming to a remote call-forwarding number to be automatically forwarded to any answering location designated by the call receiver.
Note: Customers may have a remote-forwarding telephone number in a central switching office without having any other local telephone service in that office.

1. A clock that is remote from a particular facility, such as a communications station or node, with which it is associated.
2. A clock that is remote from another clock to which it is to be compared.

Server utilized by ITF and DNG to acquire needed configuration parameters, per ATIS-0800009, Remote Configuration of Devices in the Consumer Domain for IPTV Services, and ATIS-0800017, Network Attachment and Initialization of Devices and Client Discovery of IPTV Services.

Devices used to perform monitoring, controlling, and/or supervisory functions, at a distance.

A signal transmitted at the first opportunity in the outgoing direction when a terminal detects specific defects in the incoming signal. [T1.231-1997]

1. An intelligent network element that interfaces between customer access lines and digital facilities. [T1.508-1998]
2. The digital loop carrier (DLC) multiplexer that is at the end of the DLC that is closest to the network interface (NI). [T1.216-1998]

A signal transmitted in the outgoing direction when a terminal determines that specific defects have persisted long enough to declare a received signal failure. The RFI terminology is used with SONET in this standard to promote a more descriptive and consistent terminology. [T1.231-1997]

In computer operations, a mode of operation that allows execution of job instructions received from a remote site and return of the output to the same or a different remote site via a communications link.

A remotely located subscriber line access unit which is normally dependent upon the central processor of the host office for call processing functions. [47 CFR Pt.36-A]

A feature by which a linked registration for one specified terminal address can be carried out from another terminal address. [T1.701-1994]

A login that allows a user terminal to connect to a host computer via a network or direct telecommunications link, and to interact with that host computer as if the user terminal were directly connected to that host computer. Synonym remote logon.

Synonym remote login.

A protocol that (a) provides remote operation capabilities, (b) allows interaction between entities in a distributed application, and (c) upon receiving a remote operations service request, allows the receiving entity to attempt the operation and report the results of the attempt to the requesting entity.

An extension of a local orderwire to a point convenient for personnel to perform required operational and maintenance functions.

A software process by which retrieval of a network-launched application is initiated.

1. The encrypted transmission of keys from a remote source.
2. [A] procedure by which a distant crypto-equipment is rekeyed electrically. [INFOSEC-99]

The subtending remote switching device that depends in part on its host switch for call control but is capable of providing intra-unit switching. [T1.508-1998]

The location at which there is a transition between a telecommunications carrier facility and the local lines serving the individual customers. [T1.313-1997]

Arrangement that permits the extension of TSPS functions to remote locations. [47 CFR Pt.36A]

A type of network element (NE) that contains a DUA (directory user agent), an optional local cache, and possibly other application processes such as the registration agent. The R-NE communicates with the DSA (directory system agent) via the DAP (directory access protocol). [T1.245-1997]

Acronym for ringer equivalency number.

A call-disposition category for a call processing failure. [T1.207-1998]

See busy signal.

Synonym ARQ.

1. An analog device that amplifies an input signal regardless of its nature, i.e., analog or digital.
2. A digital device that amplifies, reshapes, retimes, or performs a combination of any of these functions on a digital input signal for retransmission.
Note: The term "repeater" originated with telegraphy and referred to an electromechanical device used to regenerate telegraph signals. Use… (Read More →)

A voice-frequency transformer characterized by a closed core, a pair of identical balanced primary (line) windings, a pair of identical but not necessarily balanced secondary (drop) windings, and low transmission loss at voice frequencies.
Note: It permits transfer of voice currents from one winding to another by magnetic induction, matches line and drop impedances, and prevents direct conduction between the… (Read More →)

In teletypewriter systems, a device used to punch a tape in accordance with arriving signals, permitting reproduction of the signals for retransmission.

A telephone set that stores a group of numbers frequently called by a customer and transmits the dialing information to the central office by a single action.

Refers to a telecommunications carrier that receives numbering resources from the NANPA, a Pooling Administrator or another telecommunications carrier [that must submit an NRUF]. (FCC 00-104, §
5
2. 15 (f) (2)).

Synonym precision.

In computer and telecommunications systems, a fault that will occur each time the set of conditions causing the fault occurs.
Note: The conditions under which the fault occurs and the precision with which the fault occurs must be specified when determining the reproducibility of a fault.

1. In facsimile systems, the rate at which recorded copy is produced.
Note: The reproduction speed is usually expressed (a) as the area of recorded copy produced per unit time, such as square meters per second or (b) as the number of pages per minute.
2. In duplicating equipment, the rate at which copies are made.
Note: The reproduction speed… (Read More →)

1. In cryptosystems, the denial by one of the entities involved in a communication of having participated in all or part of the communication.
2. Denial by one of the entities involved in a communication of having participated in all or part of the communication [7498-2].

A signal from a network in response to an access request, indicating the network's readiness to accept address information. [T1.507-1996]

A signal sent by the DTE to the DCE to request the establishment of a data connection.

A signal from a receiver to a transmitter asking that a message be transmitted again. [From Weik '89]

A signal that is generated by a receiver in order to condition a remote transmitter to commence transmission. [From Weik '89]

See click-through.

1. Radiation, at the same or different wavelengths, i.e., frequencies, of energy received from an incident wave.
2. Undesirable radiation of signals locally generated in a radio receiver.
Note: Radiation might cause interference or reveal the location of the device.

Recommencement of route selection from the first point of routing control, when congestion is encountered at some intermediate switching point in the connection that is to be established.

A company that redistributes the services of a commercial carrier and retails the services to the public.

In FCC deliberations and rulings, the right of a buyer of basic telecommunication services, such as private lines, foreign exchanges, or WATS, to resell and/or share with others the unused capacity.

1. In television technology, the process of converting image information from one format (standard) to another.
Note: The conversion may, for example, affect (involve) the frame rate, the number of lines per frame, the analog resolution per scanning line, or (in digital systems) the number of pixels per scanning line.
2. In video post-production, the process of changing the image… (Read More →)

Any access customer who resells the access service obtained from an exchange carrier. [T1.251-1996]

Installed capacity of a system which is not normally utilized but can be made available when required.

Key held to satisfy unplanned needs. [INFOSEC-99]

In ISDN applications, a telecommunications service that establishes a communication path at a preset time (requested by the user) in response to a user-network signaling request.

A reserved code is an NXX code that has been temporarily set aside while the applicant awaits a decision from the appropriate regulatory authority on a safety valve waiver already submitted.

Reserved numbers are numbers that are held by service providers at the request of specific end users or customers for their future use. Numbers held for specific end users or customers for more than 180 calendar days shall not be classified as reserved numbers (FCC 00-429 §5
2. 15 (f)(1) (vi)).

In programming languages, a keyword whose definition is fixed by the programming language and which cannot be changed by the user.
Note: In Ada® and COBOL all keywords are reserved words, while Fortran has no reserved words.

The parameters initially programmed for basic operation.

A measure of the ability to duplicate controllable conditions.
Note: An example of resettability is the ability to reset the frequency controls of radio equipment.

Pertaining to computer programs that remain on a particular storage device.

Terminates the Access network and the VDSLx or ADSLx network. Also, in most telco implementations includes a router, NAT function, and Network Management functions for both the WAN and the LAN.

Synonym undetected error ratio.

1. The ratio of (a) the number of bits, unit elements, characters, or blocks incorrectly received but undetected or uncorrected by the error-control equipment to (b) the total number of bits, unit elements, characters or blocks.
2. The error ratio that remains after attempts at correction are made.

Synonym carrier noise level.

[In security, the] portion of risk remaining after security measures have been applied. [INFOSEC-99]

Data left in storage after information processing operations are complete, but before degaussing or overwriting has taken place. [INFOSEC-99]

A network of resistors to which four branches of a circuit may be connected to make them conjugate in pairs.
Note: The primary use of a resistance hybrid is to convert between 2-wire and 4-wire communications circuits. Such conversion is necessary when repeaters are introduced in a 2-wire circuit.

Synonym resolving power.

Computer software that allows user programs to interface with domain name servers.
Note: The user program may be, for example, an FTP client. [2382-pt.35]

A measure of the ability of a lens or optical system to form separate and distinct images of two objects with small angular separation.
Note 1: An optical system cannot form a perfect image of a point (i.e., point source). Instead, it performs what is essentially a Fourier transform, and the resolving power of an optical system may be expressed… (Read More →)

In an electrical circuit, the condition that exists when the inductive reactance and the capacitive reactance are of equal magnitude, causing electrical energy to oscillate between the magnetic field of the inductor and the electric field of the capacitor.
Note 1: Resonance occurs because the collapsing magnetic field of the inductor generates an electric current in its windings that charges… (Read More →)

Synonym periodic antenna.

See optical cavity.

Anything used or consumed while performing a function. The categories of resources are: time, information, objects (information containers), processors (the ability to use information), and enablers (in the context service oriented networks). Specific examples are: CPU time; terminal connect time; amount of directly-addressable memory; disk space; number of I/O requests per minute, etc [TCSEC].

An authority recognized in a Security Domain as a trusted source of security information which relates to resources (security object) [ECMA138].

The processor(s) that control access to satellite payload communications resources within an individual satellite program.

A record, within a domain name server, that describes an Internet resource.
Note: A resource record consists mainly of a domain name, its type, and a value. [2382-pt.35]

The Resp Org that effects or is responsible for processing a Resp Org Change of a Toll-Free Number on behalf on a Toll-Free Subscriber.

The Resp Org that requests, on the behalf of a Toll-Free Subscriber, that the Subscriber's Toll-Free Number be ported, and seeks to become the control or managing Resp Org of the Toll-Free Number record.

A change initiated by a Toll-Free Subscriber to move their service to a different Responsible Organization (Resp Org).

Resp Org Change – Unauthorized
A change to a Toll-Free Subscriber’s selection of Responsible Organization that was completed without authorization or following verification procedures.

A system, maintained by the TFNA that enables Resp Orgs to administer TollFree Number Resp Org Changes and store the associated Letter of Agency (LOA) along with supporting
documentation in a centralized location. This system standardizes the process of Resp Org Change
management, submission, and processing of the change requests as well as provides access to the history
of the… (Read More →)

A unique 2-character alpha code associated with the Resp Org authorized to access the 800 Service Management System (SMS/800) and manage Toll-Free Numbers for Toll-Free Subscribers.

A 5 alpha-numeric character code that designates or points to the Resp Org associated with a specific Toll-Free Number in the 800 Service Management System (SMS/800). The 5 characters begins with a unique Resp Org Entity ID, followed by 3 additional alphanumeric characters.

In data transmission, the link level logical control condition during which a given secondary station may transmit a response.

In data transmission, all frames that may be transmitted by a secondary station.

A protocol data unit (PDU) transmitted by a logical link control (LLC) sublayer in which the PDU command/response (C/R) bit is equal to "1".

A plot of the maximum response, as a function of oscillator frequency, of an array of single-degree-of-freedom (SDOF) damped oscillators subjected to the same base excitation. [T1.329-1995] Synonym shock spectrum.

The time a system or functional unit takes to react to a given input.
Note: For example, in data processing, the response time perceived by the end user is the interval between (a) the instant at which an operator at a terminal enters a request for a response from a computer and (b) the instant at which the first character… (Read More →)

In multilevel precedence and preemption, the device that controls the length of time that the call receiver of the precedence call has to accept the incoming precedence call.
Note: The length of the time is usually set in the range of 4 s to 30 s.

The entity designated to manage and administer Toll-Free Numbers for Toll-Free Subscribers within the 800 Service Management System (SMS/800).

Ability of an entity to provide service within the required time.
Note: The term timeliness is sometimes used incorrectly to mean responsiveness.

In a photodetector, the ratio of the electrical output to the optical input.
Note 1: Responsivity is usually expressed in amperes per watt, or volts per watt, of incident radiant power.
Note 2: Responsivity is a function of the wavelength of the incident radiation and the bandgap of the material of which the photodetector is made. Deprecated synonym sensitivity.

The resumption of the execution of a computer program using the data recorded at a checkpoint.

A series of significant conditions determined by the decisions taken according to the products of the demodulation process.

The bound on performance that is allowed when corrective action is taken to restore a parameter after an IAL (immediate action limit) failure. Performance as measured by a parameter is satisfactory if the value of the parameter is equal to or better than the limit. [T1.506-1989]

Of an impaired (degraded) or unserviceable telecommunications service or facility, action taken to repair it and return it to service.
Note: Permanent or temporary restoration may be accomplished by various means, such as patching, rerouting, substitution of component parts, etc.

Describes supremacy given to some Government and National Security circuits.

A class of service in which users may be denied access to one or more of the system features or operating levels.

Synonym controlled space.

In digital communications systems, a channel that has a useful capacity of only 56 kb/s (kilobits per second), instead of 64 kb/s.
Note: The restricted channel, currently common in North America, was originally developed to satisfy a ones-density limitation in T1 circuits.

In secure systems, an authorization certificate that indicates the security restrictions on documents and transactions that an entity may authorize. [After X9.45]

Storage in the signaling link control for signal units that have been transmitted but not yet positively acknowledged. [T1.226-1992]

In interactive telecommunications, a service allowing access to and retrieval of stored information, e.g., the information within a database.

Of a satellite orbiting the Earth, an orbit in which the projection of the satellite's position on the (Earth's) equatorial plane revolves in the direction opposite that of the rotation of the Earth.

The ratio, at the junction of a transmission line and a terminating impedance or other discontinuity, of the amplitude of the reflected wave to the amplitude of the incident wave.
Note 1: Return loss is usually expressed in dB.
Note 2: Return loss is a measure of the dissimilarity between impedances in metallic transmission lines and loads, or between refractive… (Read More →)

Signaling which responds to an incoming request for service or change of status.

1. A digital code having two information states, e.g., "0" and "1" or "mark" and "yyspace", in which code the signal returns to a rest state during a portion of the bit period.
2. A code form having two information states termed "zero" and "one" and having a third state or an at-rest condition to which the signal returns during… (Read More →)

Used by standard multicast implementation for loop prevention and to build the multicast distribution tree. If RPF is enabled, network elements will drop multicast packets that are received on an incorrect interface based on the unicast path back towards the source. RPF may be disabled for asymmetric network architectures but other loop prevention techniques must be implemented.

Loop signaling in which battery and ground are reversed on the tip and ring of the loop to give an "off-hook" signal when the call receiver answers.
Note: Reverse-battery signaling may be used either for a short period, or for the duration of a call, to indicate that it is a toll call.

An asymmetric cryptographic algorithm whereby (a) messages encrypted using the public key can only be decrypted by using the private key, and (b) data that are encrypted using the private key can only be decrypted by using the public key. [After X9.31]

In telephone networks, a means of controlling distant switching selections by pulsing.
Note: In revertive pulsing, the near end receives signals from the far end.

Also rf. Abbreviation for radio frequency. Of, or pertaining to, any frequency within the electromagnetic spectrum normally associated with radio wave propagation.
Note: For designation of subdivisions, see electromagnetic spectrum and its associated diagram.

See occupied bandwidth, necessary bandwidth.

1. The amount of transmitter power above that which is computed by the link designer as the minimum required to meet specified link performance.
Note: The rf power margin allows for uncertainties in (a) empirical components of the signal level prediction method, (b) terrain characteristics, (c) atmospheric conditions, and (d) equipment performance parameters.
2. At any given time in an… (Read More →)

Offering a high degree of electromagnetic shielding effectiveness.

Abbreviation for Request for Comments. The document series, begun in 1969, which describes the Internet suite of protocols and related experiments. Not all (in fact very few) RFCs describe Internet standards, but all Internet standards are written up as RFCs. [Bahorsky]

Abbreviation for radio frequency interference. See electromagnetic interference. Abbreviation for remote failure indication.

Residential Gateway

Abbreviation for red-green-blue. Pertaining to the use of three separate signals to carry the red, green, and blue components, respectively, of a color video image.
Note: The image is not NTSC-encoded; RGB typically results in higher resolution than that specified by the National Television Standards Committee.

A directional antenna that is composed of long-wire radiators that form the sides of a rhombus, the two halves of which are fed equally in opposite phase at one apex. [From Weik '89]
Note: A rhombic antenna is usually terminated at the apex opposite the driven apex, which termination makes its radiation pattern unidirectional. It is bidirectional if the opposite… (Read More →)

Abbreviation for routing indicator.

Recording Industry Association of America

1. Any cable constructed as a ribbon with parallel elements.
2. A fiber optic cable in which the optical fibers are held in grooves and laminated within a flat semirigid strip of material, such as plastic, that positions, holds, and protects them.
Note: Ribbon cables may be stacked to produce fiber optic cables with large numbers of fibers. Buffers, strength… (Read More →)

An elliptically or circularly polarized wave, in which the electric field vector, observed in any fixed plane, normal to the direction of propagation, whilst looking in the direction of propagation, rotates with time in a right-hand or clockwise direction. [NTIA] [RR] Synonym clockwise polarized wave.

Synonym Fleming's rule.

The ability to perform a pre-defined set of utilization functions on a content item. These utilization functions are the permissions (e.g., to view/hear, copy, modify, record, excerpt, sample, translate in another language, keep for a certain period, distribute. ), constraints (e.g., pay/view/hear multiple times, play/view/hear certain number of hours), and obligations (e.g., payment, tracking, information) that apply to the content… (Read More →)

The statement of utilization functions that can be performed on a Content Item and the conditions in which they can be performed.

Indicates the entity that is entitled to grant rights.

1. In telephony, a signal of specific duration and character that indicates to a user (customer, subscriber) that a calling party is engaged in an access attempt.
2. Synonym ring network. See network topology.

In a ring network, such as a token ring network, the time required for a signal to propagate once around the ring.
Note 1: Ring latency may be measured in seconds or in bits at the data transmission rate.
Note 2: Ring latency includes signal propagation delays in (a) the ring medium, (b) the drop cables, and (c) the data… (Read More →)

See network topology.

See network topology.

See round-trip delay time.

Removal of an alerting signal in response to a loop closure. [T1.407-1997]

1. The improper routing of a call back through a switching center already engaged in attempting to complete the same call.
2. In secondary surveillance radar, the presence of false targets declared as a result of transponder interrogation by side lobes of the interrogating antenna.

1. In telephony, a signal, usually consisting of an audio tone interrupted at a slow rate, provided to a caller to indicate that the called-party instrument is receiving a ringing signal.
Note: This signal may be generated by the called-party servicing switch or by the calling-party switch.
2. A ringing signal returned to a caller to indicate that one of… (Read More →)

Synonym audible ringing tone.

In telephony, a method of signaling an operator in which telephone ringing current is sent over the line to operate a lamp and cause the drop of a self-locking relay.
Note 1: Ringdown (a) is used in manual operation, as distinguished from dialing, (b) uses a continuous or pulsed ac signal transmitted over the line, and (c) may be used… (Read More →)

In telephony, a circuit in which manually generated signaling power is used to perform ringdown.

In telephony, the application of a signal to a line (a) to operate a line signal lamp or a supervisory signal lamp at a switchboard or (b) to ring a called receiver instrument.

A number determined in accordance with the Code of Federal Regulations, Title 47, part 68, which number represents the ringer loading effect on a line.
Note: A ringer equivalency number of 1 represents the loading effect of a single traditional telephone set ringing circuit. Modern telephone instruments may have a REN lower than
1. The total REN expresses the total… (Read More →)

Oscillations that occur in the output of systems after a sudden change in the input. [T1.646-1995]

In traditional telephony, a nominal period (usually approximately 6 seconds) composed of alternate (a) ringing signals (ringing current) and (b) a silent interval.

1. The alternating current (ac) component of the alerting signal. [T1.401-1988] [T1.407-1990]
2. An ac signal applied across the network interface (NI) of such magnitude, frequency, and duration to cause an electromechanical ringer to ring. Used to alert the customer installation (CI) of an incoming call. [T1.401-1998]

Slang. To encode, compress, transfer, and copy digitized audio or video data from a compact disc (CD) to a computer hard drive.
Note: Ripping is usually done with the intent of transferring those files to another user or another device.

Of an optical cable, a parallel cord of strong yarn that is situated under the jacket(s) of the cable for the purpose of facilitating jacket removal preparatory to splicing or breaking out.
Note: The rip cord is exposed by carefully removing or severing a portion of the jacket near the end of the cable. It is then grasped with the… (Read More →)

1. In a dc voltage, the alternating component that is residually retained from rectification of ac power, or from generation and commutation.
2. In a dc voltage, the alternating component that is coupled into a circuit from a source of interference.

Acronym for reduced instruction set chip, reduced instruction set computing.
Note: Pronounced "risk. "

In the approximation of a step function, the time required for a signal to change from a specified low value to a specified high value. Typically, these values are 10% and 90% of the step height.

1. The possibility that a particular threat will exploit a particular vulnerability of a data processing system. [2382-pt.8]
2. The likelihood that a successful attack will be mounted against a computer system. Risk is a function of both vulnerability and threat [CESG].

A managerial decision to accept a certain degree of risk, usually for technical or cost reasons. [2382-pt.8]

1. A systematic method of identifying the assets of a data processing system, the threats to those assets, and the vulnerability of the system to those threats. [2382-pt.8]
2. In COMSEC (communications security), an organized method of estimating or calculating the probability of compromise. [After X9.49]
3. Synonym [in INFOSEC] risk assessment.

1. See risk analysis.
2. [In INFOSEC, the] process of analyzing threats to and vulnerabilities of an information system (IS) and the potential impact the loss of information or capabilities of a system would have on national security. The resulting analysis is used as a basis for identifying appropriate and cost-effective countermeasures. [INFOSEC-99]
3. The process of reviewing the threats… (Read More →)

[The] difference between the minimum clearance or authorization of information system (IS) users and the maximum sensitivity (e.g., classification and categories) of data processed by the system. [INFOSEC-99]

[The] Process concerned with the identification, measurement, control, and minimization of security risks in information systems to a level commensurate with the value of the assets protected. [INFOSEC-99]

RSA is a public key encryption method RSA are the initials of the developers of the algorithm which was done at taxpayer expense. The basic security in RSA comes from the fact that, while it is relatively easy to multiply two huge prime numbers together to obtain their product, it is computationally difficult to go the reverse direction: to find… (Read More →)

Abbreviation for registered jack.

Abbreviation for remote job entry.

Root Mean Square

See root-mean-square pulse duration.

Reliable Multicast Transport

Radio Network Controller

Radionavigation Satellite Service

Abbreviation for receive only.

In cellular technology (mobile telephone technology), the use of a wireless telephone outside a specified tariffed geographic area defined by the service provider (which area is usually called the "home" area); outside of the home area, additional charges usually apply. [After FCC]

Computer software that runs continuously and responds automatically to a user's activity.
Note: Some robots are created for the benefit of the user, such as those that send information when a user requests it, those that perform automated searches, and those that monitor messages in a forum and delete messages that are repetitive or violate the forum's rules of netiquette.… (Read More →)

Synonym droid.

The description of a user's sphere of responsibility [CESG].
Note: May be used for enforcing access control in accordance with the principle of least privilege. Example: System Administrator.

Routing in Low power and Lossy Networks

Acronym for read-only memory.

A low-pass filter used to reduce unwanted higher frequencies.

Synonym ambient noise level.

In multimedia and virtual reality, information that may be used to select a video source, and then control the video source to provide the desired view. The ability to provide presets is optional and may not be supported in all terminals. [After T1.80
0. 08-1995]

In computer science, the highest level of a hierarchy.

The Root Cause is the primary problem which once identified and corrected will prevent the same or a similar reportable incident from recurring (i.e., why the reportable incident happened). A Root Cause should be actionable.

A single quantity, rms, characterizing a function, f(x), given by
Note: The term "rms deviation" is also used in probability and statistics, where the normalization, M0, is unity. Here, the term is used in a more general sense.

The temporal rms deviation of the impulse response of a system.

A special case of root-mean-square deviation where the independent variable is time and f(t) describes the pulse waveform.

A conductor composed of a central core surrounded by one or more layers of helically wound groups of wires.

A signaling mechanism--usually incorporated within a telephone set--that when rotated and released, generates dc pulses required for establishing a connection in a telephone system.

Hunting in which all the numbers in the hunt group are selected in a prescribed order.
Note: In modern electronic switching systems, the numbers in the hunt group are not necessarily selected in consecutive order.

In telephone systems, an electro-mechanical switching method whereby the selecting mechanism consists of a rotating element using several groups of wipers, brushes, and contacts.

[In magnetic media,] A technique used to locate a given sector, a desired track, and a specific record by continuous comparison of the read/write head position with appropriate synchronization signals.

1. The elapsed time for transit of a signal over a closed circuit.
Note: Round-trip delay time is significant in systems that require two-way interactive communication such as voice telephony or ACK/NAK data systems where the round-trip time directly affects the throughput rate. It may range from a very few microseconds for a short line-of-sight (LOS) radio system to many… (Read More →)

Deleting the least-significant digits of a number and applying some rule of correction to the part retained. [After SMPTE]

1. In communications systems operations, the geographical path that is followed by a call or message over the circuits that are used in establishing a chain of connections.
2. To determine the path that a message or call is to take in a communications network.
Note: In a Transmission Control Protocol/Internet Protocol (TCP/IP) internet, each IP datagram is routed separately.… (Read More →)

The allocation of circuits between two points over more than one geographic or physical route with no geographic points in common.

A pointer to a specific trunk group. [T1.667-1999]

A specific list of trunk groups. [After T1.667-1999]

In communications network operations, a record that indicates the interconnections between pairs of nodes in the network, and is used to produce direct routes, alternate routes, and available route tables from point to point. [From Weik '89]

Procedures that permit a signaling point to determine the accuracy and consistency of its routing data by sending a test message and analyzing the response message to determine whether the sent message traversed the expected route. [T1.226-1992]

A system, maintained by the TFNA that enables Resp Orgs to administer Toll-Free Number Resp Org Changes and store the associated Letter of Agency (LOA) along with supporting documentation in a centralized location.
A real-time, API based routing product that contains authoritative Toll-Free routing instructions downloaded from the TFN Registry.

In data communications, a functional unit used to interconnect two or more networks.
Note 1: Routers operate at the network layer (layer 3) of the ISO Open Systems Interconnection--Reference Model.
Note 2: The router reads the network layer address of all packets transmitted by a network, and forwards only those addressed to another network.

A computer program, called by another program, that may have some general or frequent use.

A category of precedence to be used for all types of messages that justify transmission by rapid means unless of sufficient urgency to require a higher precedence. [JP 1-02]

The process of determining and prescribing the path or method to be used for establishing communications sessions.

Synonym routing number, routing table.

The application of rules during the process of routing so as to chose or avoid specific networks, links or relays [7498-2].

The RDF provides routing information for an emergency session based upon the location information in a request from the LRF.

The RDF provides routing information for an emergency session based upon the location information in a request from the LRF.

In a communications system, a diagram that (a) shows all links between all switchboards, exchanges, switching centers, and stations in the system, such as the links between primary relay, major relay, minor relay, and tributary stations as well as supplementary links, (b) is used to identify the stations and links, and (c) is used to indicate tape-relay routes, transfer circuits,… (Read More →)

See routing table.

1. A group of letters assigned to indicate: (a) the geographic location of a station; (b) a fixed headquarters of a command, activity, or unit at a geographic location; and (c) the general location of a tape relay or tributary station to facilitate the routing of traffic over the tape relay networks. [JP 1-02]
2. In a message header, an… (Read More →)

The part of the message label that is used for message routing in the signaling network. It includes the destination point code, the originating point code, and the signaling link selection field. [T1.110-1992]

Synonym routing address, routing table.

The neutral, third-party entity, contracted by the Federal Communications Commission, responsible for the assignment of non-dialable p-ANI numbers to Eligible Users.

In an internet, a service protocol that is used (by routers, but not by hosts) to maintain routing tables; routing protocols are classified as either (a) interior gateway protocols, or (b) exterior gateway protocols.

A matrix associated with a network control protocol, which gives the hierarchy of link routing at each node.

Rendezvous Poin

Remote Procedure Call

Rich Presence Information Data Format

Resilient Packet Ring

Abbreviation for repeat-request. See ARQ.

Rating Region Table

Reed-Solomon (coding)

Rivest, Shamir, Adleman (cryptography)

This is the free library RSA Data Security, Inc. , made available for the purpose of implementing freeware PEM applications. It implements several encryption algorithms, including (among others) RSA. MIT PGP uses RSAREF's RSA routines to avoid the alleged patent problems associated with other versions of PGP.

Abbreviation for received signal level.

Really Simple Syndication

Rapid Spanning Tree Protocol

Resource Reservation Protocol

Remote Terminal

Abbreviation for remote trunk arrangement.

Real Time Clock

Real Time Control Protocol - eXtended Reports

Real Time and Embedded Systems

1. Real-time Transport Protocol,
2. Real Time Protocol.

Real Time Streaming Protocol

Radio Transmission Technology

Abbreviation for radio teletypewriter.

A clock containing a quartz oscillator stabilized by a rubidium standard.

A frequency standard in which a specified hyperfine transition of electrons in rubidium-87 atoms is used to control the output frequency.
Note: A rubidium standard consists of a gas cell, which has an inherent long-term instability. This instability relegates the rubidium standard to its status as a secondary standard.

A security policy based on global rules imposed for all users. These rules usually rely on a comparison of the sensitivity of the resources being accessed and the possession of corresponding attributes of users, a group of users, or entities acting on behalf of users [7498-2].

The execution of one or more computer jobs or programs.

A redundancy-reduction technique for facsimile in which a run of consecutive picture elements having the same state (gray scale or color) is encoded into a single code word.

A public radio service rendered by fixed stations on frequencies below 1000 MHz used to provide (1) Basic Exchange Telecommunications Radio Service, which is public message communication service between a central office and subscribers located in rural areas, (2) public message communication service between landline central offices and different exchange areas which it is impracticable to interconnect by any other… (Read More →)

1. A fixed station in the rural radio service used by a subscriber for communication within a central office station.
2. One or more fixed transmitters in the rural radiotelephone service that receive service from central office transmitters. [47CFR]

Abbreviation for radio and wire integration.

Required Weekly Test

Abbreviation for receive, receiver.

Abbreviation for return-to-zero.