Failed to hang up

The FXO voice subscriber line cannot detect busy tone signals sent from the PBX, so the line is in connection even if the remote end hangs up.

As shown in Figure 16, suppose Telephone A hangs up first after conversation, then PBX A plays busy tones to Router A, which disconnects the line after detecting the busy tones and sends a disconnect message to Router B. Router B sends the message to PBX B that then plays busy tones to Telephone B. The whole disconnection process is done. If the FXO voice subscriber line on Router A cannot detect the busy tone played by PBX A, the call cannot be terminated.

• If the PBX uses North American busy tone specification but the router uses European specification (the default specification), issue the area north-america command in subscriber line view on the router to change the busy tone specification. If the problem persists, proceed with the next step.

• Automatic busy tone recognition: The automatic busy tone recognition technology uses software to sample and analyze busy tones to produce a set of parameters that represent the most common patterns of busy tones. After configured with these parameters, the FXO ports can recognize different types of busy tones.

For information about the procedure of automatic busy tone recognition test, see "Busy tone detection." If the test fails, repeat the operations till the busy tones can be recognized.