User manual

Wide Bank 28 DS3 - Release 2.4 July 2004 7-15

Diagnostics & Troubleshooting

Looptests Using Built-in PRBS BERT

 Low-Speed CSU Loopup Drop with PRBS BERT ... 7-15

 Low-Speed NIU Loopup Network with PRBS BERT ... 7-16

 DS3 Loopup Network with PRBS BERT ... 7-17

Low-Speed CSU Loopup Drop with PRBS BERT

This test sends a CSU loopup code and unframed PRBS test pattern toward a CSU device on the

low-speed drop. 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 CSU loopback and PRBS test. (This example uses DS1 #1.)

(A:Active)> ds1 1 send csu loopup drop

(A:Active)> ds1 1 send prbs drop

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 csu loopdown drop

Figure 7-5 Low-Speed CSU Looptest with PRBS BERT

Trans-

ceiver

Selector

M13

Framer

Trans-

ceiver

Relays

LS Card HS Card

DS3

Send AIS

Toward DS3

Relays

DS1/E1

Send CSU Loopup

Send PRBS

Toward DS1/E1

CSU