ALARMS, TROUBLESHOOTING & TESTING
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4. 3 Test Loop
Figure 4. 3 Test loop on local DC3445
Set the local DC3445 base panel bit-switch labelled
TEST LOOP
to the
ON
position. When
the
TEST LOOP
is activated at the local DC3445, the signal received at the LINE port is
passed directly back to the link at the line interface. The signal from the DTE is looped
adjacent to the DTE port. This effectively isolates the DC3445 running the test and validates:
(a) the local DTE cable if the local DTE recognises its own transmissions.
(b) the remote DTE and its cable, the remote DC3445 and the LINE link if the remote DTE
recognises its own transmissions.
Figure 4. 4 Test loop on remote DC3445
Set the remote DC3445 base panel Bit-switch labelled
TEST LOOP
to the
ON
position.
The test loop validates:
(a) the remote DTE cable if the remote DTE recognises its own transmissions.
(b) the local DTE and its cable, the local DC3445 and the LINE link if the local DTE
recognises its own transmissions.
DC3445
DC 3445
LOCAL
DTE
REMOTE
DTE
Tx
DC3445
DC 3445
LOCAL
DTE
REMOTE
DTE
