User manual

Wide Bank 28 DS3 - Release 2.4 July 2004 7-21
Diagnostics & Troubleshooting
Testing Low-Speed Interface Operation
DS1 Metallic Loopback
1. Configure the low-speed circuits for metallic loopback. A metallic loopback is shown in Figure
7-11.
(A:Active)> ds1 1 metallic on
NOTE: Special rules exist for metallic loopback because there is only one spare quad
card (four DS1 circuits or three E1 circuits).
• No more than four DS1 or three E1 circuits can be issued a metallic loopback at one
time (the commands ds1 all metallic and ls all metallic are not valid).
• Circuits selected for metallic loopback must all be from different protection groups.
For example, the range 1-5 is not valid because 1 and 5 are in the same group.
See Figure 7-1 for information on circuit groups.
Figure 7-11 Low-Speed Metallic Loopback
2. Send a pattern from the test set on the low-speed circuits, and verify that the test set
synchronizes on the pattern without errors.
3. When the test is complete, disable metallic loopback.
(A:Active)> ds1 1 metallic off
Send AIS
Relays
Trans-
ceiver
Selector
M13
Framer
Trans-
ceiver
Relays
Spare LS Card
HS Card
Toward DS3
Looback
Relays
Trans-
ceiver
LS Card
Toward DS1/E1
DS1/E1 DS3