Chapter 4 Testing and Diagnostics FOM-E1/T1 Installation and Operation Manual
4-2 Diagnostic Tests
4.2 Diagnostic Tests Local Analog Loopback (LLB)
FOM-E1/T1 supports activation of a local loopback, which tests the performance of
the E1/T1 electrical interface of the local unit and equipment attached to it.
The data received at the E1/T1 electrical interface is looped back to the equipment
attached to it (see Figure 4-1).
E1 or T1 BERT
Coax
LOC
Position
FOM-E1/T1
Figure 4-1. Local Analog Loopback
To activate local loopback:
• Slide the front panel TEST switch to the LOC position.
The TEST LOC indicator lights up and remains lit as long as the local
loopback is active.
Remote Digital Loopback (RLB)
FOM-E1/T1 supports activation of a remote loopback, which tests 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 transmitted to the
remote electrical interface and at the same time is looped back to the local unit
(see Figure 4-2).
E1 or T1 BERT
Coax Fiber Optic
REM
Position
Local
FOM-E1/T1
Remote
FOM-E1/T1
Figure 4-2. Remote Digital Loopback
To activate remote loopback:
• Slide the front panel TEST switch to the REM position.
The TEST REM indicator lights up and remains lit as long as the remote
loopback is active.