DEFINITY Enterprise Communications Server Release 7
Maintenance for R7r
555-230-126 Issue 4
June 1999
Alarms, Errors, and Troubleshooting

5-26Fiber Fault Isolation Procedure

5
transceiver. The loopback s hown in this diagram shows only p art what test 242 does. If no lightwave transcei ver is connected to the Exp ansion Interface circuit pack, an on-board loopback is p erformed on the Expansion Interfac e circuit pack. For more information about test 242, see ‘‘EXP-INTF (Expansion Interface Circuit Pack)’’.Figure 5-4. Fiber fault isolation testsIf DS1Cs exist on the fiber link (check with list fiber-link), then additional DS1CONV loopback tests can b e run to further isolate the problem. The loopback tests are shown in Figure 5-5. For more information a bout loopbac k tests 788 and 789, see the ‘‘DS1 CONV-BD’’ section in. For more informat ion about DS1 facility loopb ack tests 797 and 799, see t he ‘‘DS1-FAC (DS1 Facility)’’ section.Figure 5-5. DS1 CONV Loopbacks
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