DEFINITY ECS Release 8.2
Administrator’s Guide
555-233-506 Issue 1
April 2000
Glossary and abbreviations
1641
line buildout
A selectable output attenuation is generally required of DTE equipment because T1 circuits require the last
span to lose 15–22.5 dB.
line port
Hardware that provides the access point to a communications system for each circuit associated with a tele-
phone or data terminal.
link
A transmitter-receiver channel that connects two systems.
link-access procedure on the D-channel (LAPD)
A link-layer protocol on the ISDN-BRI and ISDN-PRI data-link layer (level 2). LAPD provides data transfer
between two devices, and error and flow control on multiple logical links. LAPD is used for signaling and
low-speed packet data (X.25 and mode 3) on the signaling (D-) channel and for mode-3 data communicati ons
on a bearer (B-) channel.
LINL

Local indirect neighbor link

local area network (LAN)
A networking arrangement designed for a limited geographical area. Generally, a LAN is limited in range to a
maximum of 6.2 miles and provides high-speed carrier service with low error rates. Common configurations
include daisy chain, star (including circuit-switched), ring, and bus.
logical link
The communications path between a processor and a BRI terminal.
loop-start trunk
A trunk on which, after establishing a connection with a distant switching system for an outgoing call, the
system waits for a signal on the loop formed by the trunk leads before sending the digits of the called number.
loss plan
The overall plan, used in network design and management, for creating and maintaining co nsi stent signal
strength across the network. The term also applies to local management of signa l strength to achieve appropri-
ate levels for specific applications.
LSU

Local storage unit

LWC

Leave Word Calling

M
MAC

Medium access

MADU

Modular asynchronous data unit

main distribution frame (MDF)
A device that mounts to the wall inside the system equipment room. The MDF provides a connection point
from outside telephone lines to the PBX switch and to the inside telephone stations.