Nortel DMS-100 Series Reference Manual page 169

NI-2 support for Telecom Service Interface Specification (TSIS) of BS
interworking and datafill to allow data rate adaptation
Profile of basic rate access (BRA) and primary rate interface (PRI) lines
The BRA and PRI lines are important categories of ISDN service. The BRA
line services use a two-wire loop. The PRI line services use a four-wire
loop. The key attributes of an ISDN line are multiple devices that run off
each line equipment number (LEN). Another one of the key attributes of an
ISDN line are devices considered to be logical terminals (LT). To identify
these terminals, use the following parameters.
Logical terminal identifier (LTID)
The LTID provides a different logical terminal (LT), or profile, to the
exchange termination (ET). The LTID contains the following:
the LT group (LTGRP) that is the name of the group of LTs, to a
maximum of 32
the LT number (LTNUM) that is the number that identifies the LT in the
group, 1 through 1022
Terminal endpoint identifier (TEI)
The TEI identifies terminals on the same group. The Consultative
Committee on International Telegraphy and Telephony (CCITT) defines a
maximum of 128 TEIs for each ISDN loop. Northern Telecom uses a
maximum of eight TEIs defined for each loop. Northern Telecom assigns
TEI 1 and TEI 2 to devices associated with BRI B-channels. The terminal
endpoint identifiers TEI 21 through 26 are assigned to devices with BRI
D-channels.
Note: A terminal can have more than one LT.
Call appearances and feature appearances
Terminals off an ISDN line can support multiple directory numbers (DN)
and different features on programmable keys and softkeys. The Meridian
M5317 digital telephone supports the following:
call appearances (CAP), directory numbers assigned to the M5317
feature appearances (FAP), features assigned to the M5317
DMS-100 Family XPM International Translations Reference Manual XPM12 and up
Datafilling ISDN on RSC-S International 3-145
ISDN operations
(continued)