Nortel NT1R20 Description page 150

Page 126 of 290
Figure 28
MMI Network loopback test
Common
Equipment
553-3001-105 Standard 5.00 June 1999
NT5D11 Line-side T1 Interface Card
Test 3, network loopback, loops the received T1 data back toward the CPE
equipment. No test data is generated or received by the line-side 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 28 demonstrates how the signaling is looped back toward
the CPE equipment.
Meridian 1
Line side
T-1
interface
card
External
T-1 link
network
Customer
premise
T-1 link
equipment
(CPE)
553-7564