The lower-order PRBS function supports the PRBS test in the cross-connect direction.
Figure 1 shows the signal flow of a lower-order PRBS test.
Lower-Order PRBS Test in the Cross-Connect Direction
The lower-order PRBS test in the cross-connect direction is used to check whether the corresponding cross-connect section and line section are normal after tributary services are accessed. The board transmits fixed PRBSs in the cross-connect direction on the tested path and receives the PRBSs in the downstream direction of the tested path. See Figure 2. When you perform a PRBS test in the cross-connect direction, note the following:
- You need to configure a cross-connect service.
- After the tested service passes through the cross-connect board, perform a loopback on the service (determine the loopback position and level according to the actual situation). You can test the corresponding cross-connect section or line section depending on the loopback position.
