PRBS function (Pseudo-Random Binary Sequence) is a built-in function of OSN devices, intergrated by many boards. This function module is very useful for testing and maintainance, you can determine whether the working path on a tributary port is working normally, either in the line direction, or in the cross-connect direction, by checking on whether bit errors are detected in a PRBS test. This function is equivalent to a simple instrument that transmits and receives unframed services independently.
NG-SDH OSN devices use 2 kinds of data format for test. In the case of E1 services, T1 services, T3 services, and Nx64K services, the PRBS15 is transmitted; for E3 services, the PRBS23 is transmitted.
for tributary board and line board or cross-connect board, the PRBS function is called by lower-order PRBS function and higher-order PRBS function accordingly.
To use PRBS function, you need to use the U2000 NMS system of U2000 LCT / WebLCT, in the NE Explorer, select the board you'd like to conduct PRBS test, in the Configuration function tree, click PRBS Test.
In this interface, you need to select the channel on the list, and then set test parameters on the lower part, like the test duration, and then click Start to Test button, the test result will show on the diagram in real time.
If the result shows it's Invalid in yellow color, means it's not receiving any responding data from the far end, so it might have some problem on that direction.
If the results shows it's Bit Error in red color, means it's the responding data is not matching the sending data, then on that direction the line quality might compromised or the board is in mal-functioning, need to check out the possible reasons.
Green results means this direction is working normally.
