User manual

Diagnostics & Troubleshooting
Looptests Using Built-in PRBS BERT
7-16 July 2004 Wide Bank 28 DS3 - Release 2.4
Low-Speed NIU Loopup Network with PRBS BERT
This test sends a low-speed NIU loopup code and unframed PRBS test pattern toward the far-end,
which can be another Wide Bank or other NIU device. The far-end device loops back the low-speed
signal to the near-end Wide Bank. The returned signal is analyzed by the built-in Bit Error Rate
Tester (BERT) and the PRBS error rate is displayed in the hour statistics.
1. Configure for NIU network loopback and PRBS test. (This example uses DS1 #1.)
(A:Active)> ds1 1 send niu loopup
(A:Active)> ds1 1 send prbs network
2. Display PRBS error rate.
(A:Active)> hour ds1 1
3. When finished, disable loopback and PRBS.
(A:Active)> ds1 1 send off
(A:Active)> ds1 1 send niu loopdown
Figure 7-6 Low-Speed Network Looptest with PRBS BERT
Trans-
ceiver
Selector
M13
Framer
Trans-
ceiver
Relays
LS Card HS Card
Send AIS
Trans-
ceiver
Selector
M13
Framer
Trans-
ceiver
Relays
LS Card HS Card
DS3
DS3
Send NIU Loopup
Send PRBS
Toward DS3
Loop Detect
Must be Enabled
Relays
DS1/E1
DS1/E1
Local LS
Far-End LS
Relays
Near-End (Local) DS3
Far-End DS3
Send AIS
Toward DS1/E1
Wide Bank or Other NIU