Bit Error Rate Tester (Bert) - ADTRAN 6540 Installation And Maintenance Practice

SHDSL 2-Wire/4-Wire NTU Product Series Installation and Maintenance Practice
Directions
Network (to LTU)
Customer (to NTU)
Customer (to NTU)
Network (to LTU)

Bit Error Rate Tester (BERT)

The NTU provides an internal bit error rate tester (BERT) for the injection and observation of a
pseudo-random bit sequence (PRBS) to and from the SHDSL interface on a per service basis.
The BERT runs only one test at a time. When the NTU is injecting PRBS, all ones are trans-
mitted to the applicable G.703 or Nx64K port for that service. The NTU BERT provides the
following ITU-T O.150 and O.151 compliant PRBS patterns:
• ALT
• 2047
• 2E15-1
• QRSS
The observation of data on a service under test commences automatically when a BERT test is
started. The following statistics become available on the VT100 screens and by EOC response
message when polled by NMS:
• Bit Error Rate (of format from 0.00x10E-0 to 9.99x10E-9)
• Bit Error Count (the number of bit errors during the test period)
• Pattern Sync Loss Count (the number of times a PRBS pattern sync has been lost during
the test period)
• Errored Seconds (a second that contains one or more PRBS bit errors)
• Outage Seconds (a count of ten or more consecutive Error Seconds - No outage indicates
one second occurs with no errors)
• Total Elapsed Time (of format DD:HH:MM:SS)
• BERT Status
– On
– Off
26
Table 15. KEY to Symbols used in
No Loop
If an NTU:
Network Transparent
Network Non-Transparent
AIS
If an LTU:
Customer Transparent
Customer Non-Transparent
AIS
Table 14
Loopbacks
Dual Sided
Customer Transparent
Customer Non-Transparent
AIS
Network Transparent
Network Non-Transparent
AIS
61230001L1-5C