Nx Networks 3000 - Manual (Page 50)

Monitoring Your 3000 Series Secure Gateway Router
36 3000 Series User Guide
DDS CSU/DSU Module
This module has three amber status lights.
Light Indicates . . .
ALM Alarm condition indicating the loss of loop current, bi-
polar violations, loss of signal, out of service/out of
sync, out of frame, and unmatched control code.
TST Module is in loopback test mode.
LOS Loss of signal indicating that the module is unable to
sync to the incoming data stream.
ALM
DDS CSU/DSU
TST
LOS