line-route mapA map or overlay for signal communications operations that shows the actual routes and types of construction of wire circuits in the field.
line-to-line correlationIn facsimile, the correlation of object information from scanning line to scanning line.
linear analog synchronizationSynchronization in which the functional relationships used to obtain synchronization are of simple proportionality. Synonym linear analog control.
linear combinerA diversity combiner in which the combining consists of simple addition of two or more signals.
linear deviceA device for which the output is, within a given dynamic range, linearly proportional to the input.
linear keyIn video technology and image processing, a process for the selective overlay of one video image upon another, as through chroma key.
linear polarizationOf an electromagnetic wave, confinement of the E-field vector or H-field vector to a given plane.
linear predictive coding (LPC)A method of digitally encoding analog signals, which method uses a single-level or multilevel sampling system in which the value of the signal at each…
linear programming (LP)In operations research, a procedure for locating the maximum or minimum of a linear function of variables that are subject to linear constraints.
linearityThe property of a system in which, if input signals X and Y result in system output S(X) and S(Y) respectively, the input signal aX + bY will result in…
linearly polarized (LP) modeA mode for which the field components in the direction of propagation are small compared to components perpendicular to that direction.
link diversityThe process of provisioning signaling links with physically separate transmission routes between signaling points to mitigate impact of facility failures.
Link EncryptionLink encryption encrypts all of the data along a communications path (e.g., a satellite link, telephone circuit, or T1 line).
Link LayerDeprecated term for Data Link Layer. See Open Systems Interconnection--Reference Model.
link levelIn the hierarchical structure of a primary or secondary station, the conceptual level of control or data processing logic that controls the data link.
link orderwireA voice or data communications circuit that (a) serves as a transmission link between adjacent communications facilities that are interconnected by a…
link protocolA set of rules relating to data communications over a data link. Note: Link protocols define data link parameters, such as transmission code, transmission…
link quality analysis (LQA)In adaptive high-frequency (HF) radio, the overall process by which measurements of signal quality are made, assessed, and analyzed.
link setA set of signaling links directly connecting two signaling points.[T1.226-1992]
link state controlThe control that coordinates functions of the signaling link, including signal unit delimitation, signal unit alignment, error detection, error…
link status signal unitA signal unit that contains status information about the signaling link in which it is transmitted. [T1.110-1987]
link-by-link enciphermentThe individual application of encipherment to data on each link of a communications system [7498-2].
linkageThe frequency of coinheritance of a pair of genes and/or genetic markers, which provides a measure of their physical proximity to one another on a…
linked registrationA type of AllCall registration feature, the use of which combines the registrations for incoming and outgoing calls for the current terminal address in a…
linking protection (LP)In adaptive high-frequency (HF) radio, protection intended to prevent the establishment of unauthorized links or the unauthorized manipulation of…
linuxA freeware version of the Unix™ operating system.
lip synchronizationThe synchronization of audio and corresponding video signals so that there is no noticeable lack of simultaneity between them.
liquid crystal display (LCD)A display device that creates characters by means of the action of electrical signals on a matrix of liquid cells that become opaque when energized.
list addressIn e-mail, an address used by mailing list subscribers to send e-mail to be distributed to each member of a discussion list, forum, interest group…
list processorSoftware used to manage and administer a discussion-group list, an interest group list, or a mailing list. [After Bahorsky]
List ServerA list server (mailing list server) is a program, or a feature in a program, that handles subscription requests for a mailing list and distributes new…
live linkA link, on a World Wide Web file, that connects to another layer of information. [After Bahorsky]
LoadCommissions charged on the purchase or sale of mutual fund units.
load capacityIn pulse-code modulation (PCM), the level of a sinusoidal signal that has positive and negative peaks that coincide with the positive and negative virtual…
Load factorThe ratio of average energy demand (load) to maximum demand (peak load) during a specific period.
load sharingA process used to route signaling traffic over two or more signaling routes for purposes of traffic equalization or security. [T1.226-1992]
loaderA routine that reads data into main storage.
LoadingWeight at a given tire position on a car due to aerodynamics, vehicle weight and lateral G-forces in a turn.
loading characteristicIn multichannel telephone systems, a plot, for the busy hour, of the equivalent mean power and the peak power as a function of the number of voice…
loading coilA coil that does not provide coupling to any other circuit, but is inserted in a circuit to increase its inductance.
lobeA portion of an organ, such as the liver, lung, breast, thyroid, or brain.
lobe attaching unitIn a ring network, a functional unit used to connect and disconnect data stations to and from the ring without disrupting network operations.
local access and transport area (LATA)Under the terms of the Modification of Final Judgment (MFJ), a geographical area within which a divested Bell Operating Company (BOC) is permitted to…
local adaptionThe process of modifying a product that has hard-coded biases of one culture to the hard-coded biases of another culture [POSIX.0].
Local Area Network (LAN)(LAN)Computer data communications technology that connects computers at the same site.
local batteryIn telegraphy, the source of power that actuates the telegraphic station recording instruments, as distinguished from the source of power that furnishes…
local callAny call using a single switching facility. 2. Any call for which an additional charge, i.e., toll charge, is not made to the calling or called party.
local channelThe portion of a private line circuit which is included in the exchange transmission plant.
local clockA source of timing located in close proximity to an associated facility, such as a communications station, central office, or node.
local communication network (LCN)A communication network within a TMN (telecommunications management network) that supports data communication functions (DCFs) normally at [specified]…
local exchange carrier (LEC)A local telephone company, i.e., a communications common carrier that provides ordinary local voice-grade telecommunications service under regulation…
local exchange loopAn interconnection between customer premises equipment and telephone central office.
local nodeA node which interfaces directly with customer equipment. [T1.101-1999]
local officeSynonym central office. 2. A central office serving primarily as a place of termination for subscriber lines and for providing telephone service to the…
local orderwireA communications circuit between a technical control facility and selected terminal or repeater locations within the communications complex.
local referenceA local number, unambiguously identifying an SCCP (signaling connection control part) connection within one SCCP entity. [T1.110-1987]
local security environmentThat part of the security domain of a system which is under the control of the System Manager [CESG].
local sideThe portion of a device that is connected to internal facilities, such as switches, patch panels, test bays and supervisory equipment.
LocaleDetails which are dependent upon conventions and customs adopted by a particular country or culture.
Localization(LO-kal-ih-ZAY-shun) The process of determining or marking the location or site of a lesion or disease.
Location Routing Number (LRN):The ten-digit (NPA-NXX-XXXX) number assigned to a switch/POI used for routing in a permanent local number portability environment.
lock and key protection system[A] protection system that involves matching a key or password with a specific access requirement. [INFOSEC-99]
lock-in frequencyA frequency at which a closed-loop system can acquire and track a signal. See lock-in range.
lock-in rangeThe range of frequencies within which a closed-loop system can acquire and track a signal. 2.
locked modeA mode in which BitLocker Drive Encryption prevents access to the encrypted drive, either because the system components have changed or because it needs…
LockoutLockout means a labor dispute involving a work stoppage, wherein an employer withholds work from its employees in order to gain a concession from them.
log-offThe procedure that is followed by a user in closing a session, e.g., a period of terminal operation. Synonym log out.
log-periodic (LP) antennaA broadband, multi-element, unidirectional, narrow-beam antenna that has impedance and radiation characteristics that are regularly repetitive as a…
logical link control (LLC) sublayerIn a local-area-network/metropolitan-area-network (LAN/MAN) system, the part of the link level that (a) supports medium-independent data link functions…
logical signaling channelA logical channel that provides a signaling path within an information channel or within a physical signaling channel.
logical topologyOf a network, the schematic configuration that reflects the network's function, use, or implementation without regard to the physical interconnection of…
loginThe procedure that is followed by a user in beginning a session, e.g., a period of terminal operation. Synonym logon.
long lineA transmission line in a long-distance communications network. Note: Examples of long lines are TDM and FDM carrier systems, microwave radio links…
long silent intervalA silent interval during a ringing cycle or pattern that lasts at least 1200 ms. [T1.401-1998]
long wavelengthIn fiber optic communications, pertaining to optical wavelengths greater than 1 m.
long-distance callAny telephone call to a destination outside the local service area of the calling station, whether inter-LATA or intra-LATA, and for which there is a…
long-haul communicationsIn public switched networks, pertaining to circuits that span large distances, such as the circuits in inter-LATA, interstate, and international…