Nortel Networks 1000 - Manual (Page 244)

244 NT5D11 and NT5D14 Lineside T1 Interface cards
Test 1, local loopback, loops the T1 link signaling toward itself at the
backplane connector, and test data is generated and received on all
timeslots. If this test fails, it indicates that the Lineside T1 card is defective.
Figure 42 "MMI local loopback test" (page 244) demonstrates how the
signaling is looped back toward itself.
Figure 42
MMI local loopback test
Test 2, external loopback, assumes an external loopback is applied to
the T1 link. Test data is generated and received by the Lineside T1 card
on all timeslots. If test 1 passes but test 2 fails, it indicates that the T1
link is defective between the Lineside T1 card and the external loopback
location. If test 1 was not run and test 2 fails, the T1 link or the Lineside T1
card could be defective. To isolate the failure to the T1 link, tests 1 and
2 must be run in tandem.
Figure 43 "MMI external loopback test" (page
244) demonstrates how an external loopback is applied to the T1 link.
Figure 43
MMI external loopback test
Test 3, network loopback, loops the received T1 data back toward the
CPE equipment. No test data is generated or received by the Lineside
T1 card. If test 2 passes but test 3 fails, it indicates that the CPE device
is defective. If test 2 was not run and test 3 fails, the T1 link or the CPE
device could be defective. To isolate the failure to the CPE device, tests
2 and 3 must be run in tandem.
Figure 44 "MMI network loopback test"
(page 245) demonstrates how the signaling is looped back toward the CPE
equipment.
Nortel Communication Server 1000
Circuit Card Reference
NN43001-311 02.06 Standard
27 August 2008
Copyright © 2003-2008 Nortel Networks
.