Symmetricom SSU-2000 User Manual page 69

Installing Output Summer Adapters on an In-Service SSU-2000
If you choose to install Output Summer adapters on an SSU-2000 that is generating
outputs, you may experience a LOS alarm and possibly a "Module Removed" alarm.
The alarms may occur under the following conditions:
A LOS alarm will occur if you remove the output cable from the rear panel of the
SSU-2000 and that cable carries timing signals from the associated Output
module
A "Module Removed" alarm will occur if you remove an Output module from the
SSU-2000 shelf in order to place it in a slot appropriate for output summing.
Alarm conditions downstream from the SSU-2000 and in the SSU-2000 may
result when you attach the Output Summer and the protection scheme is not
identical (1 + 1 or 1-for-1) in both Output modules.
Alarm conditions downstream from the SSU-2000 and in the SSU-2000 may
result due to misalignment of framing bits when you attach the Output Summer.
The alarm conditions remain until the SSU-2000 returns to normal operating
conditions.
1. Remove the interconnect cables from the selected module pair. A LOS alarm
occurs for the affected output(s).
2. Remove the two retaining screws on each connector that the Output Summer
adapter is to be installed on.
3. Install the Output Summer Adapter and hand tighten the retaining screws.
4. Provision the affected Output modules using SynCraft or ICS or TL1 commands:
Set the desired options on the Output modules.
Restart the affected Output modules (
Save the new user configuration (
5. Install the appropriate interconnect cable to the Output Summer Adapter.
6. Dress the cables as appropriate.
You can install the Output Summer Adapters without the risk of alarms in the
following situations:
You install the Output Summer Adapter to an SSU-2000 that has two in-service
Output modules in the desired paired slot location.
You install the Output Summer Adapter to an SSU-2000 that has one in-service
Output module in one of the desired paired slot locations and you then install the
second Output module in the other slot location.
12713020-002-2 Revision F.01 – January 2007
Chapter 2 Installing the SSU-2000
).
RESTART xAy
).
SET-SAVE xAy
Making Signal Connections
SSU-2000 User's Guide 69