Lucent Technologies MERLIN LEGEND Release 6.1 User Manual

MERLIN LEGEND Communications System Release 6.1
Feature Reference 555-661-110
Issue 1
August 1998
Features
Page 500Primary Rate Interface (PRI) and T1
In Release 6.0 and later systems, T1 channels can be programmed either to
emulate voice tie trunks or data tie trunks. These trunks can be used as tandem
trunks linking networked systems. In addition, you can use drop-and-insert
equipment to supply fractional T1 use. See the
Network Reference for more
information.
T1 channels can be programmed to emulate the following types of connections:
■ Loop-start
■ Ground-start
■ T1-emulated data (56-kbps data)
■ Ear & Mouth (E&M) tie trunk
■ Direct Inward Dial
T1 service provides the following benefits:
■ Speed. Data calls to outside or network (Release 6.0 and later systems)
destinations can be made by programming a channel for T1 Switched 56
Data. This service must be supported on the far end. By allowing
high-speed digital data transmission, T1 provides the capability for
videoconferencing and Group IV (G4) fax.
■ Improved Toll Restriction. The ways in which toll restriction can be
bypassed are limited on T1 lines/trunks. Specifically, three types of toll
abuse are eliminated with T1 service:
— Because dialing is in the form of out-of-band messages that must be
generated by the system, a user cannot use a touch-tone generating
device, such as a pocket dialer, to send dialed digits directly through the
system to the line/trunk.
— Without T1 service, toll restriction can be deceived by dialing digits on a
loop-start line before the far-end switch applies dial tone. These initial
digits may indicate a local call to the system’s toll-restriction checking
while the subsequent digits, those actually recognized by the far-end
switch, may produce a toll call. This is not possible with T1 service
because every digit screened and passed on by the system’s toll
restriction is guaranteed to be received by the far-end switch.
— A T1 line’s far-end disconnect signal provides a reliable indication when
a call ends, and a new call cannot be initiated until the line has been
released from the prior call on both ends. This prevents a user on a
loop-start line, waiting off hook for the restoration of dial tone after a
previous call, from placing a second call before toll restriction is
reapplied.
■ Reliable Indication of Far-End Disconnect. This prevents an incoming
call from being blocked because a line is not released when a call is ended.
T1 supports routing by dial plan on Switched 56 data channels that are connected
to the public switched telephone network. Routing by dial plan supports call

Lucent Technologies MERLIN LEGEND Release 6.1 Specifications

General

Brand	Lucent Technologies
Model	MERLIN LEGEND Release 6.1
Category	Conference System
Language	English