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L - Symbol used to designate inductance.
LAN - Local Area Network
LAN Adapter - see Network Interface Card
Laser - Light Amplification by Stimulated Emission of
Radiation. A device which produces light with a narrow spectral
width. Used in fiber opticcommunication systems, usually single
mode, where high capacity and low attenuation are required.
LATA - Local Access and Transport Area.
Lay - The axial distance required for one cabled conductor
or conductor strand to complete one revolution about the axis
around which it is cabled.
Lay Direction - The direction of the progressing spiral
twist in while looking along the axis of the cable away from
the observer. The lay direction can be either "left"
or "right".
LCL - see Longitudinal Conversion Loss
LCTL - see Longitudinal Conversion Transfer Loss
Leakage - An undesirable passage of current over the
surface of or through a connector.
Leased Line - A private telephone line rented for the
exclusive use of a leasing customer, without interchange switching
arrangements.
LED - see Light Emitting Diode.
LF - Low frequency.
Light Emitting Diode - A semiconductor diode which emits
incoherent light when a current is passed through it. Used as
a light source in fiber optic transmission.
Link - A transmission path between two points not including
terminal equipment, work area cables, or equipment cables.
Listed - Equipment included on a list published by an
organization, acceptable to the authority having jurisdiction,
that maintains periodic inspection of production of listed equipment,
and whose listing states either that the equipment or material
meets appropriate standards or has been tested and found suitable
for use in a specified manner.
Lobe - An arm of a Token-Ring which extends from a Multistation
Access Unit (MSAU) to a workstation adapter.
LocalTalk - A low-speed form of LAN data link technology,
part of Apple Computer's AppleTalk networking scheme, that uses
a carrier sense multiple access with collision avoidance (CSMA/CA)
form of medium access control. Supports transmission at 230
Kbps.
Longitudinal Conversion Loss (LCL) - Also called near-end
unbalance attenuation, measures cable balance by comparing the
signal appearing across the pair to the signal applied between
ground and the pair, where the applied signal and the across
pair signal are at the same end of the cable.
Longitudinal Conversion Transfer Loss (LCTL) - Also called
far-end unbalance attenuation, measures cable balance by the
comparison of the signal appearing across the pair to the signal
between ground and the pair, where the applied signal is at
the opposite end of the cable from where the across pair signal
is measured.
Loopback - A type of diagnostic test in which a transmitted
signal is returned to the sending device after passing through
a data communications link or network. This test allows the
comparison of a returned signal with the transmitted signal.
Loss - The portion of energy applied to a system that
is dissipated and performs no useful work.
Lossy - Having poor efficiency. |
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