Incoming Trunks - Lucent Technologies MERLIN LEGEND Release 7.0 System Manager's Quick Reference

MERLIN LEGEND Communications System R7.0
System Manager's Quick Reference 555-670-119
Getting Started
System Overview

Incoming Trunks

Trunks are the telephone company's facilities, provided by the central office to
carry voice and/or data communications. There are a variety of trunks, each with
different capabilities, as described in the following table.
Incoming Trunks
Trunk Type Description
Loop-Start Provides incoming and outgoing calls and are intended primarily
for key systems and older PBXs. They are the simplest (often
the least expensive) and most common facilities in the
nationwide telephone network. Although they are not appropriate
for some situations, they are necessary for others (for example,
some caller identification services).
Ground-Start Provides a signal at the beginning and end of incoming and
outgoing calls to determine the availability of a trunk before the
central office routes an incoming call on it. Also, when either the
caller or the called party hangs up, the entire circuit is
disconnected and dropped.
Tie Provides private lines that directly connect two communications
systems. Using a tie trunk, a user on one system can call an
extension on another system by dialing an access code and the
extension number or simply the extension number. In Release
6.0 and later systems (Hybrid/PBX mode only), tandem tie
trunks, either analog or T1-emulated, can be used for
networking. In this case, the user dials only the non-local
extension number without an access code. In more complex tie
trunk configurations, a person can tie into another system and
use a trunk that does not exist on his or her own system.
Direct Inward Provides fast access to specific individuals; incoming DID calls
Dial (DID) can be routed directly to an extension or calling group without
system operator assistance.
Issue 1
April 1999
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