Specifications

Installation and Operation Manual Chapter 5 Troubleshooting and Diagnostics
ASMi-31 Ver. 3.0 Testing ASMi-31 5-5
 To perform the local analog loopback test:
1. Initiate local loopback via TESTS > LLB > ON (see
Figure 5-3 ).
The TST LED on the ASMi-31 front panel lights up. The modem's transmit
output is now connected to its own receiver.
2. Execute the local analog loopback with one of the following methods:
 Using the DTE configured to the half duplex operation and checking the
echoed data stream.
 Using an external BER tester.
If the BER test indicates an error-free data stream, but the DTE test
indicates a fault, verify that the cable between the DTE and ASMi-31 is
properly connected. If the problem persists, follow the DTE
manufacturer's test procedures.
3. To isolate a communication line problem, perform the LLB loopback at the
opposite end. If both LLB tests are error-free, the fault is probably in the
communication line or in the line interfaces.
4. After completing the test or correcting the fault, deactivate the local
loopback.
You can also activate the local analog loopback via the appropriate pin of the DTE
interface. The loopback activation via the DTE pins is not available for the X.21,
Ethernet and G.703 interfaces.
TESTS
LOC
LLB *ON
LLB
RLB
REM
LLB+BERT
LOC
RLB+BERT
BERT
LEDS TEST
Figure 5-3. Initiating Local Loopback
Remote Digital Loopback (RLB)
The remote digital loopback (RLB) test checks the performance of the local and
the remote ASMi-31 units and their connecting lines. The RLB sets a loop at the
remote ASMi-31 unit from the DTE coupled to the local unit (see
Figure 5-4 ).
Note