Nortel Networks 9150 - Manual (Page 38)

8 Remote Gateway 9150 Installation and Administration Guide
Remote Gateway 9150 description Standard 3.1
Add-on modules description
The Remote Gateway 9150 unit can support trunk interface modules, such as
ISDN BRI U or S/T interfaces, and up to three DSP application modules.
Optional trunk interface modules
Trunk interface modules route calls over the PSTN. The number of modules you
must install depends on the number of simultaneous calls you want to process in
host-controlled or locally controlled mode.
Note: To determine how many trunk interface modules you need for your
calling requirements, use the “Remote Gateway 9150 System expansion
worksheet” on page 385.
The Remote Gateway 9150 unit can support up to four U or S/T ISDN BRI
interfaces. Each module supports one ISDN BRI line (with two B-channels)
from the local telephone service provider. Refer to the following illustration for
an example of an ISDN BRI module:
ISDN BRI module
G101420
U interface (NTDR74xx)
S/T interface (NTDR75xx)