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5.4.2 REMOTE DIGITAL LOOPBACK (RDL)
The Remote Digital Loopback (RDL) test checks the performance
of both the local and remote Model 1065RCs,
and the communication
link between them. Any characters sent to the remote 1065RC in this
test mode will be returned back to the originating device. For example,
characters typed on the keyboard of the local terminal will appear on
the local terminal screen
after having been passed to the remote
Model 1065RC and looped back. To perform an RDL test, follow these
steps:
1.
Activate RDL. This may be done in two ways: by moving the
upper front panel toggle switch LEFT to “Remote” or by raising
pin 21 on the RS-232 interface.
2.
Verify that the DTE equipment on the local end is operating
properly and can be used for a test.
3.
Locate the lower of the two toggle switches on the front panel
of the 1065RC and move it to the right. This will activate the
V.52 BER test mode and inject a “511” test pattern into the
remote loop. If any errors are present in the loop, the red
“Error” LED will blink sporadically.
4.
If the BER test indicates
no errors are present, move the
V.52 toggle switch to the left, thus activating the “511/E” test
with periodic errors. If the test is working properly, the red
“Error” LED will blink
regularly. A successful “511/E” test will
confirm that the loop is in place, and that the Model 1065RC’s
built-in “511” generator and detector are working properly.
5.
If the remote BER test indicates that errors
are present, and
the local analog loopback/BER tests showed that both Model
1065RCs were functioning properly, this suggests a problem
with the twisted pair communication line connecting the two
modems. A common problem is improper crossing of the
pairs. Also, verify that the modular connections are pinned
properly, and the twisted pair line has continuity. If you still
have errors, call Technical Support at (301) 975-1007.
5.4.3 USING THE V.52 BER TEST INDEPENDENTLY
The Model 1065RC's V.52 BER test can be used independent of
the V.54 loopback tests. This requires two operators: one to initiate and
monitor the test at both the local and the remote Model 1065RC. To
use the V.52 BER test by itself, both operators should simultaneously
follow these steps:
1.
Locate the lower of the two toggle switches on the front panel
of the Model 1065RC and move it to the right. This will acti-
vate the V.52 BER test mode and transmit a “511” test pattern
to the other unit. If any errors are present, the receiving
modem’s red “Error” LED will blink sporadically. Note: For this
independent test to function, the “511” switch on
both Model
1065RCs must be turned on.
2.
If the test indicates no errors are present, move the V.52 tog-
gle switch to the left, thus activating the “511/E” test with peri-
odic errors present. If the test is working properly, the receiv-
ing modem’s red “Error” LED will blink
regularly. A successful
“511/E” test will confirm that the link is in place, and that the
Model 1065RC’s built-in “511” generator and detector are
working properly.
