Because RFL™ and Hubbell® have a policy of continuous product improvement, we reserve the right to change designs and specifications without notice.
LOOPBACK TESTING
A local loopback test is performed when the module is first installed, or any time the integrity of the
module needs to be checked. The loopback test can be performed on modules in terminal systems or
drop/insert systems. The loopback test is a tool for locating problems, but is no substitute for
troubleshooting expertise.
Before starting a loopback test, make sure the following conditions have been met:
1. The DS-562I module and I/O adapter must be installed in an RFL IMUX 2000 chassis.
2. Power must be applied to the system.
3. The module must be out of service.
4. If the module is set for 56 Kbps, the transmit and receive addresses must be set to the same
value, or set to zero.
A telecommunications test set that can accept RS-449/422, X.21/V.11, CCITT V.35, or CCITT G.703
signals (depending on the adapter module used), will be required for the loopback test
(Telecommunications Techniques Corporation Fireberd 2000 or equivalent).
VERIFICATION TEST
1. Press the Group toggle switch on the CM-3 left or right until the function display reads LPBK.
Then push the SET toggle switch left until the function display reads EqLB. At this time push
the SET toggle switch twice to the right.
NOTE
Equipment Loopback on the CM-3 will loopback all DS0 channels within that shelf
The green LED above the SET toggle switch should blink after the first push and
should be steady after the second push.
The yellow loopback LED on the CM-3 and the yellow LED on the power supply
should be lit, indicating that the system is in local loopback.
2. Connect a test set to the cable assembly in accordance with the manufacturers procedures.
Then perform a bit error rate test.
For test criteria, use a 63 or 511 test pattern. Alternately, use a 109 or lower bit
pattern.
RFL DS-562I RFL Electronics Inc.
June 14, 2007 36 (973)
334-3100
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