Laser – A device which transmits an extremely narrow and coherent beam of electromagnetic energy in the visible light spectrum. [Acronym for Light Amplification by Stimulation of Emission of Radiation.]
Latency – Time interval between when a network station seeks access to a transmission channel and access is granted or received.
Layer - (1) Related processes, activities or information that constitute one level in a hierarchy or network platform. (2) Related communications-processing functions that comprise one level in a hierarchy of functions within the OSI reference model.
Learning curve – A planning technique calculation based on the premise that workers are able to produce any new product more quickly after they get used to making it.
Leased line – Any communication channel leased for exclusive use from a common carrier. Synonym: private line.
Least cost routing (LCR) – Method for automatic selection of the least costly facility for transmission of a call. Synonyms: Most Economical Route Selection (MERS); Route Optimization; Automatic Route Selection; Flexible Route Selection.
Level – (1) A group of related functions, activities or occurrences. (2) Expressed as the relative signal strength at a fixed point in a communications circuit .
Lightwave communications – The use of light as the primary medium in an actual application. [Lightwave communications is sometimes used in place of "optical" to avoid confusion with image transmissions such as facsimile or television.] See fiber optics.
Limited-distance modem – (1) A short-haul modem or line driver. [Since line conditions can be better controlled over short distances, some limited-distance modems operate at higher speeds than modems that are designed for use over analog telephone facilities.]
Line – Any communications path between two or more points, including satellite or microwave channels. See channel.
Line conditioning – Adjustment and control of the properties of a leased line to bring its characteristics within specified tariff limits; generally improves the frequency response and delay considerations of the line. [Line conditioning services provided by telephone carriers are designated as Type C or D (example C1, C2 or C4).]
Line driver – A modem alternative used when transmitting via Electronics Industry Association (EIA) cable over short distances, usually several hundred feet. (2) Device to amplify signals and reshape distorted pulses.
Line loading – Use of electrical components to improve the response characteristics of a communications line.
Line printer – (1) A device that prints a line of characters as a unit. (2) A line-at-a-time printer.
Line side – A circuit from a subscriber’s telephone to the end or central office.
Link – A communications path between two nodes in a network.
Link layer – (1) The logical entity in the OSI model relative to transmission of data between adjacent network nodes. (2) The second processing level in the OSI model, between the physical and the network layers.
Loading – (1) Initializing software on a computer processing unit. (2) A means of adding regularly spaced inductance units on a circuit to improve its transmission characteristics.
Local access and transport area (LATA) – A geographical area designated by the FCC for the provision and administration of telephone service to individual customers; designated exchanges grouped to serve common social and economic communities of interest.
Local Area Data (LAD) Circuit – One or more pairs of copper wire leased from a Regional Bell Operating Company (RBOC) which in Michigan’s case is Ameritech. The quality of these wires is not guaranteed.
Local area network (LAN) – An interconnecting multiple terminals, workstations, programs, storage and graphic devices within a relatively small geographic area.
Local distribution area (LDA) - An area that includes the rate centers (NXXs) served by an originating city.
Local distribution frame(LDF) - One of the locations in a building where equipment attaches a number of cables for the communications outlets. Multiple LDFs are typically attached to one BDF.
Local exchange carrier (LEC) – (1) Provider of local telephone service. (2) The provider of service within a LATA.
Local loop – (1) The communications lines/services between the telephone subscriber and the LEC switching center. (2) The local connection between the end user and Class 5 central office or end office.
Loop – (1) A closed circuit. (2) The single connection from a switching center to an individual telecommunications instrument.
Loop back – A method of performing transmission tests on a circuit which does not require the assistance of personnel at the distant end.