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5. Diagnostics and Troubleshooting
5.1 Alarm Relay
The T3 Fiber Optic Line Driver includes a dry-contact alarm-relay port for most
major and minor alarms.
• Major alarms are initiated when a) T3 electrical input becomes lower than
G.703 electrical levels or b) bit-error rate at the fiberoptic interface is 10
-6
or
worse.
• Minor alarms occur when an Alarm Indication Signal (AIS) is received at the
T3 electrical or fiberoptic interfaces.
The dry-contact port operates as Normally Open or Normally Closed. See the
pinout below.
Figure 5-1. Alarm relay connector pinout.
NOTE
The relay positions are shown in the non-energized state (alarm active).
CHAPTER 5: Diagnostics and Troubleshooting
KEY: In Figure 5-1, NO=Normally Open and NC=Normally Closed.
