Nortel Circuit Card Installation Manual page 308

Page 308 of 906
Figure 59
MMI Local loopback test
Common
Equipment
553-3001-211 Standard 3.00
NT5D33 and NT5D34 Lineside E1 Interface cards
Table 108 shows which test to run for the associated equipment.
Table 108
MMI Tests
Test number
1
2
3
Test 1, local loopback, loops the E1 link signaling toward itself at the
backplane connector. Test data is generated and received on all timeslots. If
this test fails, it indicates that the LEI is defective. Figure 59 illustrates how
the signaling is looped back toward itself.
System
Line side
E-1
interface
card
Test 2, external loopback, applies an external loopback to the E1 link. Test
data is generated and received by the LEI on all timeslots. If test 1 passes but
test 2 fails, it indicates that the E1 link is defective between the LEI and the
external loopback location. If test 1 was not run and test 2 fails, the E1 link or
the LEI could be defective. To isolate the failure to the E1 link, tests 1 and 2
must be run in tandem. Figure 60 on
loopback is applied to the E1 link.
August 2005
Equipment Tested
LEI
E1 link, LEI, and E1
network
CPE device and E1
network
External
E-1 link
network
page 309
Test Description
Local loopback
External loopback
Network loopback
Customer
premise
E-1 link
equipment
(CPE)
demonstrates how an external
553-1160