Specifications

Common Equipment Description 2-23
Service Resource Modules
Push Buttons
The BNM-155 has two push-buttons located on the faceplate of the front card.
• Audible Cut-off (ACO) BUTTON:
The ACO button is a momentary switch and is depressed during a major or minor alarm to
deactivate the audible alarm relays and to turn the ACO LED on. Any new alarm will cause the
relays to be reactivated.
• History Clear (HIST) BUTTON:
The History Clear button is a momentary switch and is depressed to extinguish the History LED
if there is no active alarm at the time.
Service Resource Modules
A Service Redundancy Module (SRM) provides three major functions for service modules. It
provides for bit error rate testing (BERT) of T1 and E1 lines and ports, loops back individual
Nx64 channels towards the CPE, and provides 1 for N redundancy.
Two types of SRM are available
• SRM-T1E1
• SRM-3T3
The SRM-3T3 provides the additional capability of supporting multiple T1 channels over T3 lines
on the SRM and distributing those channels to T1 service modules in the shelf.
The SRM-T1E1 is a multi-purpose front card with no backcard. The SRM-3T3 is a multi-purpose
front card and backcard containing 3 T3 ports. The installation of an SRM is optional. If SRMs are
installed then a shelf with redundant ASCs and BNMs must have redundant SRMs. If a shelf has a
single ASC/BNM pair, the SRM must be installed in the appropriate slot. This is slot 15 when the
ASC/BNM pair are installed in slots 1 and 3, and slot 16 when the ASC/BNM pair are installed in
slots 2 and 4. SRMs are hot-pluggable.
• Bit Error Rate Testing (BERT)
Once a service module line or port has been put into loopback mode, the SRM can generate a test
pattern over the looped line or port, read the received looped data, and report on the error rate.
This operation can be performed on a complete T1 or E1 line, on a fractional T1 or E1 line, on a
SD0 bundle (NxDS0), or on a single DS0 channel. The SRM can support BERT only one line or
channel at a time.
BERT is capable of generating a variety of test patterns including all ones, all zeros, alternate one
zero, double alternate one zero, 2
23
-1, 2
20
-1, 2
15
-1, 2
11
-1, 2
9
-1, 1 in 8, 1 in 24, DDS1, DDS2,
DDS3, DDS4, and DDS5.
• 1 for N Service Module Redundancy
Service module redundancy provides 1 for N redundancy for multiple groups of service modules
where a group consist of N active and one standby service modules. The redundant service
module in a group must be a superset (with respect to functionality) of the cards. For example,
one group could contain all the FRSMs and another all the AUSMs.
1:N redundancy must be configured by the user. When the failure of an active card in a group is
detected by the ASC, the SRM is ordered to invoke 1:N redundancy for that group. The back card
of the failed service module now directs data to and from the standby service module. With the
SRM-T1E1, once 1:N redundancy is invoked for a group, it is not available to the other groups