Abbreviation for atto (10-18). See metric system.
- Browse Related Terms: A, AECS, AIS, C-E, CEI, EMS, ER link, ES, ESS, MHS, MIS, OSI, OSI--RM, SS7, SXS, TCB, TCS
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In a start-stop teletypewriter system, the significant condition of the signal element that immediately precedes a character signal or block signal and prepares the receiving equipment for the reception of the code elements.
- Browse Related Terms: A-condition, alphanumeric, arithmetic shift, asynchronous transmission, Baudot code, block character, code character, comma-free code, emoticon, end-of-selection character, equal-length code, FLAG, serial transmission, start-stop modulation, stroke, stroke edge, SYN, transliterate, WRU
A standard compression algorithm, used in digital communications systems of the European digital hierarchy, to optimize, i.e., modify, the dynamic range of an analog signal for digitizing. Note: The wide dynamic range of speech does not lend itself well to efficient linear digital encoding. A-law encoding effectively reduces the dynamic range of the signal, thereby increasing the coding efficiency and resulting in a signal-to-distortion ratio that is superior to that obtained by linear encoding for a given number of bits.
- Browse Related Terms: a-law algorithm, bit synchronization, mu-law (µ-law) algorithm, return-to-zero (RZ), signal element, SLIP, SONET, synchronization bit, synchronization code, synchronous optical network, synchronous transport signal level 1 (STS-1)
A call in which the call originator disconnects or cancels the call after a connection has been made, but before the call is established.
- Browse Related Terms: abandoned call, access barred signal, address message, audio response unit (ARU), automatic calling unit (ACU), backward signal, call associated signaling (CAS), call identifier, call tracing, call-failure signal, calling rate, camp-on-with-recall, controlled not-ready signal, five-hundred (500) service, forward signal, main station, nonblocking switch, outgoing access, seven-hundred (700) service, station message-detail recording (SMDR), ticketed call, videophone
Network replacement of a connect signal with an on-hook signal (network) prior to receiving a CI (customer installation) answer signal; abandonment is the only way to end an unanswered call attempt. [T1.405-1989]
- Browse Related Terms: abandonment, answer signal, call set-up error probability, call set-up failure probability, concrete signal, connect signal, emergency short-term, maximum disengagement time, partial-dial condition
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An address that has fewer characters than the full address, usually for special communications and other services or for certain users. Note: Examples of abbreviated addresses are (a) a four-digit telephone number for a user calling another user connected to the same switching exchange, and (b) message addresses that have only the addressee name and station code or number. [After Weik '96]
- Browse Related Terms: abbreviated address, Access Gateway, cable modem, Client, prefix, remote-network element (R-NE), server, speed of service, virtual terminal (VT)
Calling that enables a user to employ an address having fewer characters than the full address when initiating a call. Note: Communications network users may be allowed to designate a given number of abbreviated address codes. The allocation of the abbreviated address codes to a destination or group of destinations may be changed as required, by means of a suitable procedure. [After Weik '96]
- Browse Related Terms: abbreviated address calling, advanced intelligent network (AIN), automatic calling, automatic route selection (ARS), bell (BEL) character, BIRRDS, Call Gap, call management, call-second, community of interest, maximum calling area, national number, national prefix, NDUB (network-determined user busy), perimeter network, Rate Center, slave station, Soft Dial Tone Numbers, telephone number
A telephone service feature that (a) permits the user to dial fewer digits to access a network than are required under the nominal numbering plan, and (b) is limited to a subscriber-selected set of frequently dialed numbers. Synonym speed dialing.
- Browse Related Terms: abbreviated dialing, adjunct service point (ASP), attendant conference, basic service element (BSE), call restriction, code restriction, common user, Flash, NC code, Nonconforming End Office, preset conference, remote access, restricted access, service access, traffic monitor
In a computer or data transmission system, to terminate, usually in a controlled manner, a processing activity because it is impossible or undesirable for the activity to proceed. 2. In data transmission, a function invoked by a sending station to cause the recipient to discard or ignore all bit sequences transmitted by the sender since the preceding flag sequence.
- Browse Related Terms: abort, ADCCP, bit-sequence independence, calling sequence, flag sequence, format structure, m-sequence, media stream, random number, self-synchronizing code, unexpected frame, unnumbered command, unnumbered response
Any of a number of hard materials, such as aluminum oxide, silicon carbide, and diamond, that are powdered and carefully graded according to particle size, and used to shape and/or finish optical elements, including the endfaces of optical fibers and connectors. Note: For finishing the endfaces of optical fiber connectors, abrasive particles are adhered to a substrate of plastic film, in a fashion after that of sandpaper. The film is in turn supported by a hard, flat plate. The connector is supported by a fixture that holds it securely in the proper position for finishing. The grinding motion may be performed manually or by a machine. [After FAA]
- Browse Related Terms: abrasive, area loss, break out, buffer, cleave, mechanical splice, mechanically induced modulation, mechanically intermateable connectors, multifiber joint, numerical aperture loss, optical connector, optical section, optical time domain reflectometer (OTDR), precision-sleeve splicing, splice loss, splice organizer, terminus
In communications, computer, and data processing systems, an address that directly identifies a storage location without the use of an intermediate reference, e.g., a base address or a relative address. [After Weik '96]
- Browse Related Terms: absolute address, addressability, cache memory, computer program origin, fractal, magnetic core storage, main storage, memory, multiprocessor, processing unit, resident, spooling, virtual storage
The time interval or phase difference between transmission and reception of a signal. 2. The total time between the instant a bit enters the network and the instant a corresponding bit exists the network.[T1.503-1989] [T1.507-1996]
- Browse Related Terms: absolute delay, activity factor, baud (Bd), bias distortion, error-free second (EFS), open switching interval (OSI), phase difference, receiver release-time delay, release time, ringing cycle, signal duration, signal sampling, signal unit alignment, significant interval, start-stop distortion, synchronous transmission, tie, Time, time code ambiguity, time code resolution, time diversity, time guard band, time instability, time jitter, time scale, time standard, time-gated direct-sequence spread spectrum, uniform time scale, unit interval, virtual height
Of an antenna, for a given direction and polarization, the ratio of (a) the power that would be required at the input of an ideal isotropic radiator to (b) the power actually supplied to the given antenna, to produce the same radiation intensity in the far-field region. Note 1: If no direction is given, the absolute gain of an antenna corresponds to the direction of maximum effective radiated power. Note 2: Absolute gain is usually expressed in dB. Synonym isotropic gain. 2. Of a device, the ratio of (a) the signal level at the output of the device to (b) that of its input under a specified set of operating conditions. Note 1: Examples of absolute gain are no-load gain, full-load gain, and small-signal gain. Note 2: Absolute gain is usually expressed in dB.
- Browse Related Terms: absolute gain, antenna array, antenna blind cone, antenna efficiency, antenna electrical beam tilt, antenna gain, antenna lobe, aperture, biconical antenna, far-field radiation pattern, main lobe, near-field diffraction pattern, null, omnidirectional antenna, periscope antenna, Phased Array, radiation pattern, radiation resistance, radio beam, reference antenna, rhombic antenna, side lobe, single-polarized antenna
- Browse Related Terms: absolute temperature, antenna gain-to-noise-temperature (G/T), antenna noise temperature, carrier-to-receiver noise density (C/kT), equivalent noise resistance, equivalent noise temperature, equivalent satellite link noise temperature, noise equivalent power (NEP), noise figure (NF), noise power density, noise temperature, phase equalizer, phon, specific detectivity, terahertz (THz), thermal noise
In the transmission of electrical, electromagnetic, or acoustic signals, the conversion of the transmitted energy into another form, usually thermal. [After 2196] Note 1: Absorption is one cause of signal attenuation. Note 2: The conversion takes place as a result of interaction between the incident energy and the material medium, at the molecular or atomic level.
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A spectral region in which the absorption coefficient reaches a relative maximum, by virtue of the physical properties of the matter in which the absorption process takes place. [FAA]
- Browse Related Terms: absorption, absorption band, absorption index, Absorptivity, F layer, material absorption, path loss, phonon absorption, Photoelectric Effect, photovoltaic effect, sudden ionospheric disturbance (SID)
A measure of the attenuation caused by absorption of energy that results from its passage through a medium. [After 2196] Note 1: Absorption coefficients are usually expressed in units of reciprocal distance. Note 2: The sum of the absorption coefficient and the scattering coefficient is the attenuation coefficient.
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