Telecommunications — page 5 of 85

Telecommunications terms

401. ARQ Abbreviation for automatic repeat-request. Error control for data transmission in which the receiver detects transmission errors in a message and…
402. array An Array is a single server type used for horizontal scaling. It may be a single worker slave task plugged into our Grid system to scale based on the…
403. array processor A processor capable of executing instructions in which the operands may be arrays rather than data elements. Synonym vector processor.
404. arrester A device that protects hardware, such as systems, subsystems, circuits, and equipment, from voltage or current surges produced by lightning or…
405. ARS Abbreviation for autonomous(ly) replicating segment (or sequence).
406. art line Synonym [loosely] artificial transmission line.
407. article Synonym posting.
408. articulation index A measure of the intelligibility of voice signals, expressed as a percentage of speech units that are understood by the listener when heard out of context.
409. articulation score (AS) A subjective measure of the intelligibility of a voice system in terms of the percentage of words correctly understood over a channel perturbed by…
410. Artifact An object produced or shaped by human beings and of archaeological or historical interest.
411. Artificial Intelligence (AI) The subfield of computer science concerned with the concepts and methods of symbolic inference by computer and symbolic knowledge representation for use…
412. artificial transmission line A four-terminal electrical network, i.e. an electrical circuit, that has the characteristic impedance, transmission time delay, phase shift, and/or other…
413. ARU Alignment Reference Unit (PAC-3).
414. ASCII An acronym for American Standard Code that allocates a number to each key on the keyboard and that can be traded and read by most computer systems.
415. ASP (1) Airborne Surveillance Platform. (2) Advanced Sensor Program. (3) Advanced Sensor Platform. (4) Annual Service Practice.
416. Aspect Ratio The relationship of the height and width of any image. The aspect ratio of an image must be maintained to prevent distortion.
417. assemble To translate a computer program expressed in an assembly language into a machine language.
418. assembler The program used to translate a program written in assembly language into the binary form of a particular instruction set.
419. Assembly Putting sequenced fragments of DNA into their correct chromosomal positions.
420. assembly language A symbolic language corresponding closely to the instruction set of a Central Processing Unit.
421. assembly program Synonym assembler.
422. assembly time The elapsed time taken for the execution of an assembler.
423. Asset Anything owned that has value; any interest in real property or personal property that can be used for payment of debts.
424. assigned frequency The center of the assigned frequency band assigned to a station. [RR] 2. The frequency of the center of the radiated bandwidth.
425. assigned frequency band The frequency band within which the emission of a station is authorized; the width of the band equals the necessary bandwidth plus twice the absolute…
426. Assigned Numbers: Assigned numbers are numbers working in the PSTN under an agreement such as a contract or tariff at the request of specific end users or customers for…
427. Assignment Assignment occurs when someone who has written, or sold, a listed option receives a notice that the option has been exercised and he or she must fulfill…
428. assignment (of a radio frequency or radio frequency channel) Authorization given by an administration for a radio station to use a radio frequency or radio frequency channel under specified conditions. [NTIA] [RR]
429. associated common-channel signaling Common-channel signaling in which the signal channel is associated with a specific trunk group and terminates at the same pair of switches as the trunk…
430. associated mode of signaling The mode in which messages for a signaling relation involving two adjacent signaling points are conveyed over a directly interconnecting signaling link.
431. associative storage A storage device whose storage locations are identified by their contents, or by a part of their contents, rather than by their names or positions.
432. Assurance One of the five Security Goals. It involves support for our confidence that the other four security goals (integrity, availability, confidentiality, and…
433. asymmetric compression A data compression technique that requires more processing capability to compress than to decompress.
434. asymmetric cryptographic algorithm A cryptographic formula that uses two related keys-a public key and a private key-each of which has the characteristic algorithm that, given the public…
435. asymmetric digital subscriber line (ADSL) An access technology that allows voice and high-speed data to be sent simultaneously over local exchange service copper facilities; the technology…
436. asymmetric encryption An encryption system that utilizes two keys, one called a public key (which is known to both the sender and the recipient of encrypted data), and the…
437. asymmetrical modulator Synonym unbalanced modulator.
438. asynchronous communications system A data communications system that uses asynchronous operation. Note: The time spacing between successive data characters or blocks may be of arbitrary…
439. asynchronous multiplexed transmission system A multiplexed transmission system in which the rates of the carrier and its tributaries are not traceable to the same master clocking source.
440. asynchronous network A network in which the clocks do not need to be synchronous or mesochronous. Synonym nonsynchronous network.
441. asynchronous operation A sequence of operations in which operations are executed out of time coincidence with any event. 2.
442. asynchronous time-division multiplexing (ATDM) Time-division multiplexing in which asynchronous transmission is used.
443. asynchronous transfer mode (ATM) A network technology that combines the features of cell-switching and multiplexing to offer reliable and efficient network services.
444. asynchronous transmission Data transmission in which the instant that each character, or block of characters, starts is arbitrary; once started, the time of occurrence of each…
445. asynchronous working Synonym asynchronous operation.
446. AT Commands A de facto standard for modem commands from an attached CPU, used in most 1,200 and 2,400 b/s modems.
447. ATB (1) Allied Test Bed. (2) Analytical Tool Box.
448. ATDM Adaptive Time Division Multiplexer.
449. ATM Anti-Tactical Missile.
450. ATM (asynchronous transfer mode) connection A virtual channel connection (VCC) or a virtual path connection (VPC). [T1.627-1993]
451. ATM (asynchronous transfer mode) layer connection An association established by the ATM Layer to support communication between two or more ATM service users (i.e.
452. ATM (asynchronous transfer mode) transport system A transport system composed of a carrier system terminated by an ATM multiplexer at each end. The relationship between input and output, i.e.
453. ATM link (asynchronous transfer mode link) A virtual path link (VPL) or a virtual channel link (VCL). [T1.627-1993]
454. ATM switch (asynchronous transfer mode switch) With reference to both analog and digital interfaces, the ATM functional unit and technology that operates with analog 2-wire interfaces and standard…
455. atmospheric duct A horizontal layer in the lower atmosphere in which the vertical refractive index gradients are such that radio signals (a) are guided or focused within…
456. atmospheric noise Radio noise caused by natural atmospheric processes, primarily lightning discharges in thunderstorms.
457. atomic time See International Atomic Time.
458. ATOW Acronym for acquisition and tracking orderwire. A downlink circuit that provides a terminal with information regarding uplink acquisition and…
459. Attachment Taking a person's property to satisfy a courtordered debt.
460. attachment unit interface (AUI) In a local area network, the interface between the medium access unit (MAU) and the data terminal equipment within a data station.
461. attack An attempt to violate computer security. Note: An example of an attack is malicious logic. [2382-pt.8] 2.
462. attack time The time between (a) the instant that a signal at the input of a device or circuit exceeds the activation threshold of the device or circuit and (b) the…
463. attendant access loop A switched circuit that provides an attendant with a manual means for call completion and control.
464. attendant conference A network-provided service feature that allows an attendant to establish a conference connection of three or more users.
465. attendant position The part of a switching system used by an attendant, i.e., an operator, to assist users in call completion and use of special services.
466. attention character In [a] trusted-computing-base (TCB) design, a character entered from a terminal that tells the TCB the user wants a secure communications path from the…
467. attention signal The attention signal to be used by AM, FM, and TV broadcast stations to actuate muted receivers for inter-station receipt of emergency cuing announcements…
468. Attenuation A mechanism for controlling gene expression in prokaryotes that involves premature termination of transcription.
469. attenuation coefficient The rate of diminution of average power with respect to distance along a transmission path.
470. attenuation constant The real part of the propagation constant in any electromagnetic propagation medium.
471. attenuation distortion The difference in loss at specified frequencies relative to the loss at 1004 Hz, unless otherwise specified. [NECA/FCC-5]
472. attenuation rate Synonym attenuation coefficient.
473. attenuation-limited operation The condition that prevails when attenuation, rather than bandwidth, limits the performance of a communications link.
474. attenuator A nucleotide sequence in the 5' region of a prokaryotic gene (or in its RNA ) that causes premature termination of transcription, possibly by forming a…
475. attribute An attribute is a characteristic of data that sets it apart from other data, such as location, length, or type.
476. Attribute Authority An entity, recognized by the Federal Public Key Infrastructure (PKI) Policy Authority or comparable Agency body as having the authority to verify the…
477. attribute certificate A set of attributes and a public key certificate identifier that are made unforgeable by use of the digital signature created with a private key.
478. ATV all-terrain vehicle.
479. audible Synonym for audible ringing tone.
480. audible ringing An audible signal (information tone) transmitted to the calling party when the called party is alerted. [T1.401-1988]
481. audible ringing tone In telephony, a signal, usually consisting of an audio tone interrupted at a slow repetition rate, provided to a caller to indicate that the called-party…
482. audio channel A means for delivering audio signals from one point to another. An audio waveform submitted to the channel input results in a similar (not necessarily…
483. audio dubbing 1. In videotape editing, a process or technique employed to (a) enhance (e.g., remove noise from, or introduce some kind of special effect into), (b) add…
484. audio frame A presentation unit of the audio channel; a group of consecutive audio samples.
485. audio frequency (AF) The band of frequencies (approximately 20 Hz to 20 kHz) that, when transmitted as acoustic waves, can be heard by the normal human ear.
486. audio response unit (ARU) A device that provides synthesized voice responses to dual-tone multifrequency signaling input by processing calls based on (a) the call-originator input…
487. audio-follow-video A video recording, mixing or switching technique or process in which the audio signal associated with any given video signal is recorded, switched, or…
488. Audit An audit is a professional, independent examination of a company's financial statements and accounting documents following generally accepted accounting…
489. audit event An activity which may cause an audit record to be reported in an audit trail. The POSIX.6/D13.1 option specifies the audit events corresponding to POSIX.
490. audit event type A field within an audit record that identifies the activity reported by the record, and defines the required content of the record [POSIX.6].
491. audit ID >An identifier for the individual user accountable for an audit event [POSIX.6].
492. audit information >Information recording security events in the system [ECMA138].
493. audit record The discrete unit of data reportable in an audit trail on the occurrence of an audit event [POSIX.6].
494. audit record field A field containing information regarding all entities in a transaction, and indicators of the types of processing performed by those entities. [After X9.
495. audit recorder function >A function that records the security-relevant messages in a security audit trail [10181-7].
496. audit review file A file created by executing statements included in a computer program for the explicit purpose of providing data for auditing.
497. Audit Trail In computer security systems, a chronological record of when users logged in, how long they were engaged in various activities, what they were doing, and…
498. audit trail analyzer function >A function that checks a security audit trail in order to produce, if appropriate, security alarm messages [10181-7].
499. audit trail archiver function A function that archives a part of the security audit trail [10181-7].
500. audit trail collector function A function that collects individual audit trail records into a security audit trail [10181-7].