R2511-HP MSR Router Series Voice Configuration Guide(V5)

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Troubleshooting analog voice subscriber line
configuration
Failed to hang up
Symptom
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.
Figure 16 Network diagram
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.
Solution
• 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.