T1 BERT Test: Error, Loopback Plug, HDLC, PPP Multilink

T1 BERT Test (Bit Error Rate Testing) Example


T1 BERT TestBERT (Bit Error Rate Testing) is an important tool to test channelized line card cabling and signal problems. The BERT test sends a pattern down the line and expects to receive the same pattern in return – this is accomplished via a strategically placed loop.

The loop may be put up on the smartjack itself, by making a T1 loopback plug (pin 1 to pin 4 and pin 2 to pin 5) or placing a pre-made loopback plug on the cable end.

BERT Testing Example

Here’s an example configuration on a Cisco router to execute the test after the loop has been put up on the corresponding cable or jack.

If the T1 is in a PPP Multilink bundle, remove it first then set the encapsulation to HDLC.

 

Validate

 

Run the qrss pattern at a 10 minute interval

 

Check status and results then remove the test

 

Run the 1s pattern at a 2 minute interval

 

Check status and results then remove the test

 

Run the 0s pattern at a 2 minute interval

 

Check status and results then remove the test

 

If needed, reset the encapsulation to ppp and place the T1 in the multilink bundle.

See also:
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