1. PRI includes 3 layers before we can make a call through PRI, we need to make sure the first two layers work normally. Layer 1 indicates physical connection while layer 2 indicates the synchronization between Yeastar and the PRI provider.
Note: this guide also applies to the BRI line.
2. Debug commands under Asterisk CLI.
1) Check the physical layer:
dahdi show status
Description Alarms IRQ bpviol CRC4 Fra Codi Options LBO
RED 0 0 0 CCS AMI YEL 0 db
OK 0 0 0 CCS AMI YEL 0 db
OK means layer 1 connected successfully. RED means disconnected.
under asterisk CLI, you can check layer 2 with command:
2) Check the data link layer:
pri show spans
PRI span 1/0: Provisioned, Up, Active
PRI span 2/0: Provisioned, Down, Active
Up means layer 2 synchronize correctly, Down means synchronize failed.
3) Check the application layer:
pri set debug 2 span X：Turn on PRI debug for span X
pri set debug off span X：Turn off PRI debug for span X
X is the span number you got at step 2).