measured blocking thresholdA value for measured blocking above which there is a statistically significant probability that the design blocking objective is not being met. [T1.
measured-rate serviceTelephone service for which charges are made in accordance with the total connection time of the line.
mechanical spliceOf optical fibers, a splice, i.e., permanent joint, accomplished by aligning the mating fibers in some kind of mechanical fixture.
mechanically induced modulationOptical signal modulation induced by mechanical means. Note: An example of deleterious mechanically induced modulation is speckle noise created in a…
mechanically intermateable connectorsConnectors that are mechanically mateable, without creating mechanical damage, and without regard to attenuation properties.
Mechanismthe means by which an effect or change is produced.
media streamA sequence of presentation units intended to convey some specific content. [T1.801.04-1997]
MediationMediation is an informal, voluntary method of resolving disputes, in which the parties in conflict meet with a trained, independent third party to come up…
mediation functionIn telecommunications network management, a function that routes or acts on information passing between network elements and network operations.
medium(pl.: media) 1. In plant tissue culture, a term for the liquid or solid formulation upon which plant cells, tissues or organs develop.
medium access unit (MAU)In a communications system, the equipment that adapts or formats the signal for transmittal over the communication medium.
medium frequency (MF)Frequencies from 300 kHz to 3000 kHz. See electromagnetic spectrum.
medium interface connector (MIC)In communications systems, the connector at the interface point between the bus interface unit and the terminal, i.e., the medium interface point.
medium interface point (MIP)In communication systems, the location at which the standards for the interface parameters between a terminal and the line facility are implemented.
medium-power talkerA hypothetical talker, within a log-normal distribution of talkers, whose volume lies at the medium power of all talkers determining the volume…
medium-term bit error rateBit error rate that can be encountered for relatively short time periods (e.g., minutes), due to temporary malfunctions of, for example, transmission…
megahertz (MHz)A unit of frequency denoting one million (106) Hz.
memoryData storage in the form of chips, or the actual chips used to hold data; storage is used to describe memory that exists on tapes or discs.
memory scavengingThe collection of residual information from data storage. [INFOSEC-99]
menuA list of options, each of which performs a desired action such as choosing a command or applying a particular format to a part of a document.
MERCASTAcronym for merchant-ship broadcast system.
merchant-ship broadcast system (MERCAST)A maritime shore-to-ship broadcast system in which the ocean areas are divided into primary broadcast areas each covered by a high-powered shore radio…
meridional rayIn fiber optics, a ray that passes through the optical axis of an optical fiber (in contrast with a skew ray, which does not).
mesochronousThe relationship between two signals such that their corresponding significant instants occur at the same average rate.
messageIn the Java Message Service, an asynchronous request, report, or event that is created, sent, and consumed by an enterprise application and not by a human.
message alignment indicatorIn a signal message, data transmitted between the user part and the message transfer part to identify the boundaries of the signal message.
message authenticationDetermining that a message has not been changed since leaving its point of transmission, where: (a) the identity of the originator is verified, and (b)…
Message Authentication Code (MAC)A cryptographic checksum on data that uses a symmetric key to detect both accidental and intentional modifications of the data.
message body1. For the single message format, the message words. 2. For the multiple message format, the parameter messages. [After T1.401-1998]
message broadcastAn electronic-mail conference capability using data terminals. Note: Control can be maintained by the user or by the network.
Message DigestA cryptographic checksum, typically generated for a file that can be used to detect changes to the file; Secure Hash Algorithm-1 (SHA-1) is an example of…
message element1. In e-mail, a specified portion of a message (e.g., the header, the body). [ANSDIT] 2.
message externalsInformation outside of the message text, such as the header, trailer, etc. [INFOSEC-99]
message feedbackA method of checking the accuracy of transmission of data by sending received data back to the sending end for comparison with the original data that have…
message formatA predetermined or prescribed spatial or time-sequential arrangement of the parts of a message that is recorded in or on a data storage medium.
message frameA frame that consists of the channel seizure signal, the mark signal, the message, the checksum word, and any possible filler marks. [T1.401-1998]
message handling system (MHS)In the ITU-T X.400 Recommendations, the family of services and protocols that provides the functions for global electronic-mail (e-mail) transfer among…
message headingIn radio communications, the message part or parts that (a) precede the text, i.e.
message indicator[A] sequence of bits transmitted over a communications system for synchronizing crypto-equipment. Some off-line cryptosystems, such as the [. . .
message partIn radio communications, one of the three major subdivisions of a message, namely the heading, the text, or the ending.
message register leadsTerminal equipment leads at the interface used solely for receiving dc message register pulses from a central office at a PBX so that message unit…
message serviceSwitched service furnished to the general public (as distinguished from private line service).
message signal unit (MSU)A signal unit that contains service information and signaling information fields and is retransmitted by the signaling link control if it is received in…
message switchingA method of handling message traffic through a switching center, either from local users or from other switching centers, whereby the message traffic is…
message transfer agent (MTA)An OSI application process used to store and forward messages as described in the X.400 message handling system. [Bahorsky] Synonym Internet mail agent.
message transfer partThe part of a common-channel signaling system that transfers signal messages and performs associated functions, such as error control and signaling link…
message typeAn assigned value used to identify the feature generating the message. [T1.401-1998]
message type codeThe mandatory one-octet field that uniquely defines the function and format of each ISDN user-part message. [T1.110-1987]
message unitA unit of measure for charging telephone calls, based on parameters such as the length of the call, the distance called, and/or the time of day. 2.
message wordThe smallest unit of data in the message body. This normally contains the actual feature data that a subscriber at the customer installation (CI) is…
messaging serviceIn integrated services digital networks (ISDN), an interactive telecommunications service that provides for information interchange among users by means…
metaOf or relating to that portion of an HTML document that is not viewable by users through normal use of the browser window, but is readable by search…
meta certificateA certificate, issued to a signatory authority, that displays all co-signature requirements for its signatory certificates. [After X9.45]
meta nameA meta key word that is incorporated in the head of an HTML document, and that includes the document's name and facilitates indexing for search engines.
meta-signaling VCs (vacant codes)The standardized vacant codes that convey meta-signaling information across a user-network interface (UNI). [T1.627-1993]
metallic circuitA circuit in which metallic conductors are used and in which the ground or earth forms no part.
metallic memberA noncommunications metallic cable component such as a shield, vapor barrier, or strength member. [T1.316-1997]
metric systemA decimal system of weights and measures based on the meter as a unit of length and the kilogram as a unit of mass.
metropolitan area network (MAN)A data communications network that (a) covers an area larger than a campus area network and smaller than a wide area network (WAN), (b) interconnects two…
metropolitan service areaThe area around and including a relatively large city and in which substantially all of the message telephone traffic between the city and the suburban…
micro-mainframe linkA physical or logical connection established between a remote microprocessor and mainframe host computer for the express purpose of uploading…
microbendIn an optical waveguide, sharp curvatures involving local axial displacements of a few micrometers and spatial wavelengths of a few millimeters.
microbend lossIn an optical fiber, the optical power loss caused by a microbend. [2196]
microcodeA sequence of microinstructions that is fixed in storage that is not program-addressable, and that performs specific processing functions.
microcomputerA computer (a) in which the processing unit is a microprocessor and (b) that usually consists of a microprocessor, a storage unit, an input channel, and…
microfinishing filmA film of dimensionally stable plastic, to which are adhered carefully graded abrasive or polishing powders, i.e.
microinstructionAn instruction that controls data flow and instruction-execution sequencing in a processor at a more fundamental level than machine instructions.
MicroprocessorA processor on the RAID card which performs all RAID management functions.
microprogramA sequence of microinstructions that are in special storage where they can be dynamically accessed to perform various functions.
microwave (mw)Loosely, an electromagnetic wave having a wavelength from 300 mm to 10 mm (1 GHz to 30 GHz).
Mie ScatteringAny scattering produced by spherical particles whose diameters are greater than 1/10 the wavelength of the scattered radiation.
mileageIn telecommunications, a specified distance used in tariff calculations, i.e., toll charge calculations.
military common emergency frequencyA frequency that (a) is used by all military units that are equipped to operate at that frequency or in the band in which that frequency lies and (b) is…
millimeter waveLoosely, an electromagnetic wave having a wavelength from 1 mm to 0.1 mm (300 GHz to 3000 GHz).
minimizeA condition wherein normal message and telephone traffic is drastically reduced in order that messages connected with an actual or simulated emergency…