Nortel Networks 553-3001-211 manual MMI Tests Test number Equipment Tested Test Description, Lei

Page 296 of 894 NT5D33 and NT5D34 Lineside E1 Interface cards

Table 103 shows which test to run for the associated equipment.

Table 103

MMI Tests

Test number	Equipment Tested	Test Description
1	LEI	Local loopback
2	E1 link, LEI, and E1	External loopback
	network
3	CPE device and E1	Network loopback
	network

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 56 illustrates how the signaling is looped back toward itself.

Figure 56

MMI Local loopback test

	System
Common	Line side		External		Customer
	E-1	E-1 link		E-1 link	premise
Equipment	interface		network		equipment
	card				(CPE)
					553-1160

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 57 on page 297 demonstrates how an external loopback is applied to the E1 link.

553-3001-211 Standard 2.00 September 2004