Troubleshooting
Fiber link fault isolation
172
Maintenance Procedures
December 2003
Test #242 can be run as part of the test board UUCSS long command for an EI circuit pack. Besides
testing on-board components, this test is helpful for isolating problems between a circuit pack and the
lightwave transceiver. The loopback shown in this diagram shows only part of what Test #242 does. If no
lightwave transceiver is connected to the EI circuit pack, an on-board loopback is performed on the EI
circuit pack. For more information about Test #242, see
EXP-INTF (Expansion Interface Circuit Pack)
Maintenance Alarms Reference (555-245-102).
Figure 24: Tests for isolating fiber faults
If DS1-CONVs exist on the fiber link (check with list fiber-link), then additional DS1CONV loopback
tests can be run to further isolate the problem. The loopback tests are shown in
on page 172. For more information about DS1-CONV Loopback Tests (#788 and #789), see:
•
Far-End DS1 Converter Circuit Pack Loopback Test (#788)
•
Far-End Lightwave Transceiver Loopback Test (#789)
For more information about DS1 Facility Loopback tests (#797 and #799), see:
•
Far-End Internal Loop-Back Test (#797)
•
Near-End External Loop-Back Test (#799)
Figure 25: DS1 CONV Loopbacks
Table 59, DS1 interface cable connectors,
on page 173 shows the pin assignments for the cable used to
connect the TN574 DS1 CONV circuit pack to DS1 facilities.
Tone
Clock
Tone
Detector
Test
#242
fiber-optic
cable
TDM BUS
back skin
of cabinet
lightwave
transceivers
TN753
Switch
Node
Interface
Test
#757
Test
#756
TN570
Expansion
Interface
back skin
of cabinet
Test #989 (framing)
Test #238 (framing)
Tests 788, 780, 797,
and 799 start here:
. . . .
.
.
.
.
.
.
.
.
.
.
.
. . . .
Test 797 loops at internal
interface for the DS1 facility
Test 789
loops here
Test 788
loops here
lightwave
transceiver
DS1 Facility
CSU 2
DS1C
2
CSU 1
DS1C
1
Test 799
LB 1
Test 799
LB 2
Summary of Contents for CMC1
Page 1: ...Maintenance Procedures 555 245 103 Issue 1 1 December 2003 ...
Page 14: ...Contents 14 Maintenance Procedures December 2003 ...
Page 416: ...Additional maintenance procedures IP Telephones 416 Maintenance Procedures December 2003 ...
Page 426: ...Index X 426 Maintenance Procedures December 2003 ...