Page 5
61291021L5-5A
Section 61291021L5-5A, Issue 1
Initiating OCU Latching Loopback to Loop the
TRDDS-R (US West Only)
•
SW1-6 on the TRDDS-DP must be ON to enable
latching loopback response.
•
From a test system or set, send an OCU latching
loopback sequence.
•
Send a selected test pattern and test for error-free
operation.
•
Upon completion of this test, advance to
Terminating OCU, CSU or NIE Latching
Loopback
for latching loopback termination.
Initiating CSU Latching Loopback to Loop a
DSU/CSU (US West Only)
•
SW1-6 on the TRDDS-DP must be ON to enable
latching loopback response.
•
From a test system or set, send a CSU latching
loopback sequence. This instructs the TRDDS-
DP to notify the TRDDS-R of a CSU loopback
request. The TRDDS-R will reverse sealing
current to the DSU/CSU. The DSU/CSU should
loop when reversed sealing current is detected.
•
Send a selected test pattern and test for error-free
operation.
•
Upon completion of this test, advance to
Terminating OCU, CSU or NIE Latching
Loopback
for latching loopback termination.
Network Interface Equipment Latching
Loopback
The NIE latching loopback method can be used to loop
the TRDDS-R at all rates. This loopback test may
require programming of the loopback select code or
the complete sequence into the test system.
Terminating OCU, CSU or NIE Latching
Loopback
• From a test system or set, send a Latching
Loopback Disable command (35 TIP bytes).
Total Reach Dataport Bidirectional Loopback
Support
The Total Reach dataport will execute a bidirectional
loopback when performing a loopback at the dataport.
The Total Reach dataport responds to either the OCU
or DS0 loopback command, whichever loopback is
applicable to the dataport version. Refer to Table 7 for
Total Reach dataport loopback support.
Table 5. Latching Loopback Sequences
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Table 6. Alternating Loopback Sequences
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