8. Testing
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5. From the DCLB screen, press the Function key for the port for which you want
to perform the data channel loopback. Use the scroll keys, if necessary.
Test Started appears on Line 2. If a Data Channel loopback is already in
progress, the Already Active message appears. If an invalid combination
of loopbacks is in progress, the error message Invld Test Combo appears
(see Table8-2, Valid Loopback Combinations, for valid loopback test
combinations).
Data Terminal Loopback (DTLB)
The Data Terminal Loopback command (DTLB) loops the data received from the
selected port, for all DS0 channels allocated to the port, back out of t he port. This
loopback occurs after the data passes through the port circuitr y but before it
reaches the T1 framer.
Procedure
To perform a Data Terminal loopback:
1. From the top-level menu screen, select Test.
2. From the Test screen, select Lpbk.
3. From the Loopback screen, press the key until the DTLB selection appears
on the screen.
F1 F2 F3
Loopback: DCLB
Prt1 Prt2 Prt3
496-14314-02
CSUDSU
NETWORK
INTERFACE
DTE
(DSX-1)
ALL 1s
DTLBDTLB
PORT 1PORT 2
F1 F2 F3
Test:
Rlpbk Lpbk Ptrns