To perform a loopback BERT, proceed with the following steps:
- Set the Rx Input Termination to term.
- Select the correct Framing and line coding.
- Plug into the NTWK OUT jack with the test set Rx cable and plug the Tx cable into the NTWK IN jack.
- Select Internal as the Tx clock source.
- Select the Bert pattern you want to test with.
- Loop up the far end CSU loop code by selecting CSU loop code and pressing the loop Up key.
- Verify that no bit errors occur for each BERT pattern used in testing. Be sure to clear errors after changing BERT patterns.
- Loop the CSU Down when testing is complete.
This test will identify problems, but will not identify on which side of the span the problem is located.