Loop Telecom IP6610, User Manual

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Chapter 4 Maintenance
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If the remote facility responds to a remote loopback activate command, a LOOPED message appears in the
lower left corner of the display. If the remote facility responds to a remote loopback deactivate command, a
NOLOOP message appears. If the remote activation/deactivation fails, an error message appears.
It is best to use remote loopbacks in conjunction with QRSS diagnostics testing to measure the DS1 network
line integrity. The procedure is as follows:
1. Send a remote loopback command to cause the remote facility to perform a loopback.
2. Activate the QRSS diagnostics test.
4.4 Test Pattern
Three test patterns are available to determine faults such as deficient clock recovery, fault ALBO level
recovery, inadequate jitter margin, presence of bridge taps, and mis-optioned network interface. These four
patterns are described in the following paragraph.
4.4.1 3-in-24 Pattern
This framed 3-in-24 pattern is transmitted within 31 DS0 channels. It tests the consecutive zeros
requirement and useful to test AMI circuits.
The 3-in-24 pattern sequence is as follows,
(TS0) 01000100 00000000 00000100 01000 . . . . . (Left to Right)
(TS0) indicates frame alignment channel.
4.4.2 1-in-8 Pattern
This framed 1-in-8 pattern tests the ability of a circuit to support a pattern having the minimum ones density.
It is useful to reveal a timing recovery problem.
Framed 1-in-8 pattern sequence is as follows,
(TS0) 01000000 01000000 0100 . . . . . (Left to Right)
(TS0) indicates frame alignment channel.
4.4.3 2-in-8 Pattern
This framed 2-in-8 pattern, in conjunction with the 1-in-8 Pattern, is useful when performing tests to reveal
the presence of equivalent mis-optioned for HDB3. Use of 2-in-8 pattern will confirm the circuit's ability to
support error free transmission when HDB3 substitution do not occur. When use this pattern frame
alignment channel's Si (international bit) and Sa4 to Sa8 (FDL data link) must be set to 1. A framed 1-in-8
will cause a HDB3 substitution.
Framed 2-in-8 pattern sequence is as follows,
(TS0) 01000100 01000100 01 . . . . (Left to Right)
(TS0) indicates frame alignment channel.