long-term bit error rateBit error rate measured over a sufficiently long period, for example, one month. [T1.226-1992]
long-term stabilityOf an oscillator, the degree of uniformity of frequency over time, when the frequency is measured under identical environmental conditions, such as supply…
longitudinal balanceThe electrical symmetry, with respect to ground, of the two wires of a pair 2. An expression of the difference in impedance of the two sides of a circuit.
longitudinal balance-audioThe ratio of the disturbing longitudinal source voltage, Vs, and the resultant metallic voltage, Vm, at the same frequency of the network under test…
longitudinal voltageA voltage induced or appearing along the length of a transmission medium. Note 1: Longitudinal voltage may be effectively eliminated by using differential…
loop closureA condition in which the network presents a low-resistance tip-to-ring dc path at the network interface (NI). [T1.407-1990]
loop compensation lossThe loss that could be provided by a digital loop carrier system or a fiber-in-the-loop system when a short customer analog access cable results in…
loop filterIn a phase-locked loop, a filter located between the phase detector (or time discriminator) and the voltage controlled oscillator (or phase shifter).
loop gainThe total usable power gain of a carrier terminal or two-wire repeater. Note: The maximum usable gain is determined by, and may not exceed, the losses in…
loop noiseThe noise contributed by one or both loops of a telephone circuit to the total circuit noise.
loop openA signal in which the network applies a high resistance between the tip and ring conductors at the network interface (NI). [T1.407-1997]
loop startA supervisory signal given by a telephone or PBX in response to completing the loop path.
loop testA test that uses a closed circuit, i.e., loop, to detect and locate faults.
loop transmissionMultipoint transmission in which (a) all the stations in a network are serially connected in one closed loop, (b) there are no cross-connections, (c) the…
loop-backA method of performing transmission tests of access lines from the serving switching center, which method usually does not require the assistance of…
looped dual busA distributed-queue dual-bus (DQDB) scheme in which the head-of-bus functions for both buses are at the same location.
LoranLong Range Navigation, a system of long range navigation whereby latitude and longitude are determined from the time displacement of radio signals from…
loran stationA long distance radionavigation land station transmitting synchronized pulses. Hyperbolic lines of position are determined by the measurement of the…
LossThe amount an insurance company pays on a claim.
Loss DeviationThe term "Loss Deviation" denotes the variation of the actual loss from the designed value.
lossless compressionExact construction of image, bit-by-bit, with no loss of information.
lossy compressionReduces storage size of image by reducing the resolution and color fidelity while maintaining minimum acceptable standard for general use.
lossy mediumA medium in which a significant amount of the energy of a propagating electromagnetic wave is absorbed per unit distance traveled by the wave. [After 2196]
lost blockA block not delivered to the user within a specified maximum end-to-end block transfer time.
lost callA call that has not been completed for any reason other than cases where the call receiver (termination) is busy.
lost frameA frame that is not delivered to the destination user within an agreed-upon measurement period, and the network is responsible.
low-level modulationModulation of a signal, e.g., a carrier, at a point in a system or device, such as a radio transmitter, where the power level is low compared to the final…
low-level signalingThe use on signal lines of voltage levels that are between the limits of positive and negative 6 volts. Synonym low-level keying.
low-pass filterA filter network that passes all frequencies below a specified frequency with little or no loss, but strongly attenuates higher frequencies.
low-performance equipmentEquipment that has imprecise characteristics that do not meet system reliability requirements. 2.
low-power communication deviceA restricted radiation device, exclusive of those employing conducted or guided radio frequency techniques, used for the transmission of signs, signals…
lowest usable high frequency (LUF)The lowest frequency in the HF band at which the received field intensity is sufficient to provide the required signal-to-noise ratio for a specified time…
LPAbbreviation for linear programming, linking protection.
luminance range1. In CRT displays, the difference in brightness between the lightest and the darkest element of a scene or its display. [After SMPTE] 2.
luminance signal1. In television technology, the signal that describes (a) the distribution of brightness levels within the image and (b) the equation for deriving that…
lurkerIn the Internet, a participant in a chat room or a subscriber to a mailing list or newsgroup who passively observes but does not actively participate in…
lurkingPassive participation in (i.e., monitoring) the activities of a mailing list, a newsgroup, an IRC channel, a video connection, or any other Internet…
lynxA World Wide Web browser that provides a character-based user interface to hypertext-based information.
M-patch bayA patching facility designed for patching and monitoring digital data circuits at data signaling rates from 1 Mb/s (megabits per second) to 3 Mb/s.
M-PEGAbbreviation for Motion Picture Experts Group. 2. In digital television signal recording or transmission, the designator that identifies a certain coding…
MAC(1) OBSOLETE. Military Airlift Command. See AMC. (2) Maintenance Allocation Chart.
MAC labelAn attribute of a subject or object which represents the sensitivity of the subject or object and is used for mandatory access control decisions.
machine instructionAn instruction that is written in a machine language and can be executed directly by the processor for which it was designed without translation or…
machine languageA language that need not be modified, translated, or interpreted before it can be used by the processor for which it was designed.
machine learningThe ability of a device to improve its performance based on its past performance.
machine-independentIn telecommunications, computer, and data processing systems, pertaining to operations, procedures, computer programs, and processing that do not depend…
machine-readable mediumA medium capable of storing data in a form that can be accessed by an automated sensing device.
macrobendA relatively large-radius bend in an optical fiber, such as might be found in a splice organizer tray or a fiber-optic cable that has been bent.
macrobend lossIn an optical fiber, that loss attributable to macrobending. Synonym curvature loss.
magnetic cardA card with a magnetizable surface on which data can be stored and retrieved.
magnetic circuitThe complete closed path taken by magnetic flux. 2. A region of ferromagnetic material, such as the core of a transformer or solenoid, that contains…
magnetic core storageIn computer technology, a storage device that uses ferromagnetic materials such as iron, iron oxide, or ferrite and in such shapes as wires, toroids, and…
magnetic drumA right circular cylinder with a magnetizable surface on which digital data can be stored and retrieved.
Magnetic remanenceThe strength of the magnetic field that remains in a tape or magnetic particle after it is (1) exposed to a strong, external magnetic field and (2) the…
magnetic stormA perturbation of the Earth's magnetic field, caused by solar disturbances, usually lasting for a brief period (several days) and characterized by large…
magnetic tapeA magnetically coated strip of plastic on which analog or digital data can be encoded See also storage media.
magneto-ionic double refractionThe combined effect of the Earth's magnetic field and atmospheric ionization, whereby a linearly polarized wave entering the ionosphere is split into two…
magneto-optic effectAny one of a number of phenomena in which an electromagnetic wave interacts with a magnetic field, or with matter under the influence of a magnetic field.
mail exchange record (MX record)An entry in a domain name system database that directs the routing of mail by mail transfer agents. [After Bahorsky]
mail exploderPart of an e-mail delivery system that allows a message to be automatically and efficiently delivered to a list of addresses, thus implementing mailing…
mail gatewayA computer that connects two or more electronic mail systems (especially dissimilar mail systems on two different networks) and transfers messages between…
mail pathA series of machine names used to direct electronic mail from one user to another. [Bahorsky]
mail reflectorSynonyms e-mail exploder, mail exploder. 2. A program that forwards e-mail to individuals at a (usually) unchanging e-mail address, even when the…
mail user agentThe software used to access and manage a user's electronic mail. [After Bahorsky]
mailbox-type facilityA facility in which a message from an originating user is stored until the destination user requests delivery of that message.