Telecommunications — page 46 of 85

Telecommunications terms

4501. Mailing List A collection of e-mail addresses of people who have asked to receive regular mail discussions on a particular topic, and for which they can sometimes…
4502. mailing list server Synonym list server.
4503. mailserver A computer that provides e-mail management and storage space for messages pertaining to a group of subscribers. [Bahorsky]
4504. Main Beam The primary directional EMR emitted from radar transmitters.
4505. main distribution frame (MDF) A distribution frame on one part of which the external trunk cables entering a facility terminate, and on another part of which the internal user…
4506. main frame Synonym (in telephony) main distribution frame.
4507. main lobe Of an antenna radiation pattern, the lobe containing the maximum power (exhibiting the greatest field strength). Note: The horizontal radiation pattern, i.
4508. main station A user instrument, e.g., telephone set or terminal, with a distinct call number designation, connected to a local loop, used for originating calls, and on…
4509. main storage In a computer, program-addressable storage from which instructions and other data may be loaded directly into registers for subsequent execution or…
4510. mainframe A class of powerful, general purpose computers that can manage large amounts of data at high speed.
4511. maintainability A characteristic of design and installation, expressed as the probability that an item will be retained in or restored to a specified condition within a…
4512. maintenance The patent fees due at 4, 8 and 12 years needed to keep a U. S. utility or plant patent in force for its full life.
4513. maintenance control circuit (MCC) In a communications link, a circuit used by maintenance personnel for coordination.
4514. maintenance hook A trapdoor in software that allows easy maintenance and development of additional features and that may allow entry into the program at unusual points or…
4515. maintenance key Key intended only for in-shop use. [INFOSEC-99]
4516. major lobe See main lobe.
4517. make interval 1. In dial-pulse signaling, that portion of the dial pulse in which the network applies a low resistance between the tip and ring conductors at the…
4518. malicious applets Small application programs automatically downloaded and executed that perform an unauthorized function on an information system (IS). [INFOSEC-99]
4519. Malicious Code Software or firmware intended to perform an unauthorized process that will have adverse impact on the confidentiality, integrity, or availability of an…
4520. malicious logic A program implemented in hardware, firmware, or software, and whose purpose is to perform some unauthorized or harmful action.
4521. MAN The Unix program that displays online documentation (manual pages) for you.
4522. man-machine system A system in which the functions of a human operator and a machine are integrated.
4523. managed object In a network, an abstract representation of network resources that are managed.
4524. management domain A collection of one or more management systems, and zero or more managed systems and management subdomains, that is administered by a single organization.
4525. management information system (MIS) An organized assembly of resources and procedures required to collect, process, and distribute data for use in decision making.
4526. management inhibit A procedure used in signaling traffic management to keep a signaling link unavailable to user-part-generated signaling traffic except for test and…
4527. management system An application process within a management domain that affects monitoring and control functions on managed objects, management subdomains, or both.
4528. managing system Synonym management system.
4529. Manchester code A code in which (a) data and clock signals are combined to form a single self-synchronizing data stream, (b) each encoded bit contains a transition at the…
4530. mandatory access control (MAC) 1. Access control based on access rights granted by the System Security Officer [CESG].
4531. mandatory fixed part Part of a message that contains those parameters that are mandatory and of fixed length for a particular message type. [T1.110-1987]
4532. mandatory variable part Part of a message that contains mandatory parameters of variable length. [T1.110-1987]
4533. mandrel wrapping In multimode fiber optics, a technique used to modify the modal distribution of a propagating optical signal.
4534. manipulation detection 1. A procedure that is used to detect whether data have been modified either accidentally or intentionally. Synonym modification detection. [2382-pt. 8] 2.
4535. manipulation detection code (MDC) In cryptosystems, a bit string that is a function of data to which it is attached for the purpose of manipulation detection.
4536. manual remote rekeying [A] procedure by which a distant crypto-equipment is rekeyed electrically, with specific actions required by the receiving terminal operator. [INFOSEC-99]
4537. Margin See Margin, or margin costs
4538. marine broadcast station A coast station which makes scheduled broadcasts of time, meteorological, and hydrographic information. [NTIA]
4539. marine utility station A station in the maritime mobile service consisting of one or more hand-held radiotelephone units licensed under a single authorization.
4540. maritime air communications Communications systems, procedures, operations, and equipment that are used for message traffic between aircraft stations and ship stations in the…
4541. maritime broadcast communications net A communications net that is used for international distress calling, including international lifeboat, lifecraft, and survival-craft high-frequency (HF)…
4542. maritime mobile service A mobile service between coast stations and ship stations, or between ship stations, or between associated on-board communication stations; survival craft…
4543. maritime mobile-satellite service A mobile-satellite service in which mobile Earth stations are located on board ships; survival craft stations and emergency position-indicating…
4544. maritime radionavigation service A radionavigation service intended for the benefit and for the safe operation of ships. [NTIA] [RR]
4545. maritime radionavigation-satellite service A radionavigation-satellite service in which Earth stations are located on board ships. [NTIA] [RR]
4546. Mark -- see trademark
4547. mark sequence A string of mark bits (sent immediately before message transmission starts) to alert the customer installation (CI) to initiate certain actions. [T1.
4548. marker beacon A transmitter in the aeronautical radionavigation service which radiates vertically a distinctive pattern for providing position information to aircraft.
4549. Marking Human readable word or phrase acting as an indicator of all or part of the security constraints that apply to a document so marked [CESG]. See also: Label.
4550. marking bias The uniform lengthening of all marking signal pulse widths at the expense of the pulse widths of all spacing pulses.
4551. marking end distortion See end distortion.
4552. marking pulse Synonym mark.
4553. marking signal Synonym mark.
4554. marquee In computer display, a line of alphanumeric characters that scrolls through, and within, a defined area (window). 2.
4555. Martian 1. [Slang] Pertaining to packets that are delivered to the wrong network as the result of bogus routing entries. [After Bahorsky] 2.
4556. maser Acronym for microwave amplification by stimulated emission of radiation. A member of the general class of microwave oscillators based on molecular…
4557. mask In communications systems, to obscure, hide, or otherwise prevent information from being derived from a signal.
4558. masked threshold The level at which an indistinguishable signal of interest becomes distinguishable from other signals or noise.
4559. masking 1. In television and video technology, a process in which color signals are used to modify each other for the purpose of altering their color rendition.
4560. masquerade 1. The pretense by an entity to be a different entity in order to gain unauthorized access. [2382-pt.8] 2.
4561. Masquerading When an unauthorized agent claims the identity of another agent it is said to be masquerading.
4562. master clock A device that generates periodic, accurately spaced signals that are used for such purposes as timing, regulation of the operations of a processor, or…
4563. master file (MF) the unique mandatory file containing access conditions and optionally DFs (dedicated files) and/or EFs (extended frames). [T1.707-1998]
4564. master frequency generator In frequency-division multiplexing (FDM), equipment used to provide system end-to-end carrier frequency synchronization and frequency accuracy of tones.
4565. master key Within a hierarchy of encrypting keys and transaction keys, the highest level of key-encrypting key. [After X9.24]
4566. master oscillator Synonym master frequency generator.
4567. master station In a data network, the station that is designated by the control station to ensure data transfer to one or more slave stations.
4568. master-slave timing Timing in which one station or node supplies the timing reference for all other interconnected stations or nodes.
4569. mastergroup See group.
4570. matched junction A waveguide component having four or more ports, and so arranged that if all ports except one are terminated in the correct impedance, there will be no…
4571. matching gel See gel.
4572. material absorption See absorption.
4573. material dispersion See dispersion.
4574. material dispersion coefficient [M(λ)] In an optical fiber, pulse broadening per unit length of fiber and unit spectral width, usually expressed in picoseconds per…
4575. material scattering Of an electromagnetic wave, scattering that is attributable to the intrinsic properties of the material through which the wave is propagating.
4576. matrixing The accomplishment of a color coordinate transformation by computational, electrical, optical, or by other means. [After IEEE 100] [After SMPTE]
4577. matte An image or signal that represents or carries only transparent information that is intended to overlay or control another image or signal. [After SMPTE]
4578. MAU Abbreviation for medium access unit.
4579. maximal-ratio combiner A diversity combiner in which (a) the signals from each channel are added together, (b) the gain of each channel is made proportional to the rms signal…
4580. maximum block transfer time The maximum allowable waiting time between initiation of a block transfer attempt and completion of a successful block transfer.
4581. maximum calling area Geographic calling limits permitted to a particular access line based on requirements for the particular line.
4582. maximum disengagement time The maximum allowable waiting time between initiation of a disengagement attempt and successful disengagement.
4583. maximum justification rate Synonym maximum stuffing rate.
4584. maximum keying frequency In facsimile systems, the frequency in hertz numerically equal to the spot speed divided by twice the X-dimension of the scanning spot.
4585. maximum modulating frequency In a facsimile transmission system, the highest picture frequency that is required.
4586. maximum stuffing rate In a bit-stream, the maximum rate at which stuffing bits can be inserted into the stream. Synonym maximum justification rate.
4587. maximum time interval error (MTIE) The maximum error for all possible measurement intervals within the measurement period. [T1.101-1999]
4588. maximum usable frequency (MUF) In radio transmission using reflection from the regular ionized layers of the ionosphere, the upper frequency limit that can be used for transmission…
4589. maximum user signaling rate The maximum rate, in bits per second, at which binary information can be transferred in a given direction between users over the telecommunications system…
4590. Maxwell's equations A set of partial differential equations that describe and predict the behavior of electromagnetic waves in free space, in dielectrics, and at…
4591. Mbone Abbreviation for multicast backbone on the Internet. A part of the Internet designed to support IP multicasting by coordinating the transmission of…
4592. MCC Mesoscale Convective Complex. A large MCS, generally round or oval-shaped, which normally reaches peak intensity at night.
4593. MCM Multi-Chip Module. 178
4594. MD5 (Message Digest Algorithm #5) The message digest algorithm used in PGP is the MD5 Message Digest Algorithm, placed in the public domain by RSA Data Security, Inc.
4595. MDF Abbreviation for main distribution frame.
4596. meaconing A system of receiving radio beacon signals and rebroadcasting them on the same frequency to confuse navigation.
4597. mean power (of a radio transmitter) The average power supplied to the antenna transmission line by a transmitter during an interval of time sufficiently long compared with the lowest…
4598. mean time between failures (MTBF) A measure of the reliability of an item. Defined as the total functioning life of an item divided by the total number of failures within the population…
4599. mean time between outages (MTBO) In a system, the mean time between equipment failures that result in loss of system continuity or unacceptable degradation.
4600. mean time to repair (MTTR) The total elapsed time for corrective maintenance divided by the total number of corrective maintenance actions during a given period of time.