Nortel Networks Circuit Card - Manual (Page 311)

NT5D33 and NT5D34 Lineside E1 Interface cards Page 311 of 906
Circuit Card Description and Installation
send a call to the VRU, and, because the LEI supports analog (500/2500-type)
telephone functionality, the VRU is able to send the call back to the system
for further handling.
The LEI can also be used to provide off-premise extensions to remote
locations, up to 500 miles from the system. In this application, analog
telephone functionality is extended over E1 facilities, providing a telephone
at a remote site with access to analog (500/2500-type) telephone line
functionality. See Figure 63. Audible Message Waiting Indicator can be
provided as well.
Figure 63
LEI in off-premise extension application
Similarly, use the LEI to provide a connection between the system and a
remote Norstar system. See Figure 64 on
page 312 . In this case, channel
banks are not required if the Norstar system is equipped with an E1 interface.
Note: Consider LEI audio levels when determining the appropriateness
of an application.