Status Indicators and Alarm Relay 4-1
Chapter 4 Testing and Diagnostics This chapter describes the FOM-E1/T1 diagnostics functions, which include:
• Front panel LED indicators
• Alarm relay
• Diagnostic loopbacks.
In addition, this chapter provides some tips on troubleshooting and frequently
asked questions.
4.1 Status Indicators and Alarm Relay
Front Panel LEDs
The status of FOM-E1/T1 is indicated by the front panel LED indicators. For
description of LED indicators and their functions, refer to Chapter 3.
Alarm Relay
FOM-E1/T1 supports dry contact alarm relay via reserved pins of the DB-15 female
connector. The following fault conditions trigger relay of the major and minor
alarms:
• Major alarms are initiated when E1/T1 electrical input becomes lower than
G.703 electrical levels, or bit error rate at the fiber optic interface is 10-6 or
worse.
• Minor alarms occur when an Alarm Indication Signal is received at the E1/T1
electrical or fiber optic interfaces.
Table 4-1 lists the DB-15 connector pins used for the alarm relay.
Table 4-1. DB-15 Connector, Alarm Relay Pins
Pin Contact Alarm Type
7, 8 Normally Closed
15, 8 Normally Open Minor
5, 6 Normally Closed
13, 6 Normally Open Major