Nortel Networks 9150 - Manual (Page 88)

58 Remote Gateway 9150 Installation and Administration Guide
Planning for Remote Gateway 9150 unit installation Standard 3.1
The Remote Gateway 9150 unit ships with the ability to support up to 32 users,
with up to 8 simultaneous calls (providing a 4:1 call blocking ratio). By adding
additional DSP application or trunk interface modules, you can reduce or
eliminate call blocking.
Reducing call blocking between the Remote Gateway 9150 unit and
the host PBX
Each DSP application module provides the ability to support eight more
simultaneous calls when voice traffic is routed over the IP network. Up to three
more DSP application modules can be installed in the Remote Gateway 9150
unit, allowing 32 active calls at one time.
Note: If you add DSP capacity to the Remote Gateway 9150 unit, you must add
the same DSP capacity to the RLC on the host PBX.
Trunks are required for the Remote Gateway 9150 unit to operate in PSTN mode
(that is, over the PSTN instead of the IP network). Trunks are used to route calls
between the Remote Gateway 9150 unit and the host PBX or the local PSTN.
By default, the Remote Gateway 9150 unit ships with no trunks installed. Trunks
can be provided by installing trunk interface modules.
The number of trunks you can install depends on the type of trunk interface
modules used on the Remote Gateway 9150 unit. For example, if ISDN BRI
trunks are used, each trunk interface module provides one BRI trunk (providing
two B-channels). You can install up to four trunk interface modules in the
Remote Gateway 9150 unit.
Note: The Remote Gateway 9150 unit supports only ISDN BRI S/T or U trunks.
Calculating system requirements
To determine how many DSP application or trunk interface modules are needed
to reduce or eliminate call blocking, use the “Remote Gateway 9150 System
expansion worksheet” on page 385.