Installation and Operation Manual
Chapter 4 Troubleshooting and Diagnostics
FOM-E1/T1 Ver. 2.0
Testing FOM-E1/T1
4-3
4.3 Testing
FOM-E1/T1
Local Loopback (LLB)
FOM-E1/T1 supports local loopbacks that test the electrical interface of the local
unit, the performance of the E1/T1, and equipment attached to the interface.
Data received at the E1/T1 electrical interface is returned (looped back) to the
attached equipment. Also, if the AIS switch is set ON, the AIS is sent to the
remote unit (see
Figure 4-1
).
FOM-E1/T1/R does not transmit AIS to the remote unit when the LLB is initiated.
E1 or T1 BERT
Electrical
LOC
Position
FOM-E1/T1
Fiber Optic
AIS
Figure 4-1. Local Analog Loopback
To activate a local loopback:
1. Set SW2 (RLB/LLB) of the rear panel DIP switch to the OFF (LLB) position.
2. Set SW1 of the rear panel DIP switch to the ON (LOOP ENABLE) position.
The TEST LOC indicator lights up and remains lit as long as the local
loopback is active.
Remote Loopback (RLB)
FOM-E1/T1 supports remote loopbacks that test the performance of the local
unit's E1/T1 electrical and optical interfaces and the remote unit's optical
interface.
The data received at the optical interface of the remote unit is looped back to
the local unit. In addition, if the switch AIS is set to on, the AIS is sent to the
remote electrical interface (see
Figure 4-2
).
FOM-E1/T1/R does not transmit AIS to the electrical interface, when the RLB is
initiated.
E1 or T1 BERT
Electrical
Electrical
Fiber Optic
REM
Position
Local
FOM-E1/T1
Remote
FOM-E1/T1
AIS
Figure 4-2. Remote Loopback
Note
Note