AT&T MERLIN LEGEND System Reference Manual page 636

Glossary
IROB (in-range out-f-building) protector
A surge protection device for off-premises telephones at a location within 1000 feet of cable distance from the
communications system control unit.
ISDN 7500B Data Module
A data communications device that allows connection between RS-232 data terminal equipment (DTE) and the
communications system control unit via MLX station jacks on the 008 MLX module. The ISDN 7500B Data Module is used
together with a modem in a modem pool to change digital data signals to analog signals. and vice versa, which allows
transmission between digital and analog data stations.
J
jack
A device, accessed by inserting a plug, that is used to terminate the permanent wiring of a circuit.
K
Key
A mode of operation in which the communications system uses direct facility terminations (DFTs) on line buttons with a
separate path for internal calling.
L
LED (light-emitting diode)
A semiconductor device that produces light when voltage is applied. LEDs show the operational status of hardware
components, the results of maintenance tests, the alarm status of circuit packs, and the activation of telephone features.
line and trunk assignment
The assignment of lines and trunks connected to the communications system control unit to specific buttons on each
telephone.
line coding
The pattern data assumes as it is transmitted over a communications channel.
line compensation
An adjustment for the amount of cable loss in decibels (dBs), based on the length of cable between a DS1 module and a
channel service unit (CSU) or other far-end connection point.
line/trunk and station module
A module on which the jacks for connecting central office (CO) lines/trunks and/or the jacks for connecting the stations are
located.
local area network (LAN)
A networking arrangement designed for a limited geographical area.
local host computer access
A method for connecting a station jack to an on-site computer for data-only calls through a modem or data module.
logical ID
A numbering sequence used to identify station and line/trunk locations on the communications system control unit.
Glossary GL-9