ADTRAN 4200659L4, 4200659L1 Vt Bert, Only one T1 port may engage a CSU LOOPBACK, CSU LOOPBACK

Chapter 6. Diagnostics

Only one T1 port may engage a CSU LOOPBACK, CSU LOOPBACK

W/BERT, or a LINE BERT. If a CSU LOOPBACK, CSU LOOPBACK

W/BERT, or a LINE BERT is already active at the time a new CSU

LOOPBACK, CSU LOOPBACK W/BERT, or LINE BERT is selected, the

former test will be terminated and the latter test will be engaged.

Figure 6-7. Diagnostics Menu with BERT Selected

VT BERT

AVT BERT enables the MX2800 STS-1 to perform a “head-to- head” BERT test towards the STS-1 network. Selecting VT BERT will replace all incoming T1/E1 traffic for the T1/E1 mapped to the selected VT with an unframed QRSS pattern towards the network. When VT BERT is selected, additional menu items will appear to show the state of pattern synchronization, cumulative error count, and a clear error count option. Selecting DATA MODE will cease QRSS pattern generation and substitution of the incoming data stream. See Figure 6-8 on page 6-7 for an illustration of this test.

When in VT BERT mode, only the DATA MODE option for the VT/Port under test may be selected. Selecting any other option will cause an error message to be displayed.

6-6 MX2800 STS-1 User Manual 61200659L1-1