[asterisk-users] FreePBX: How to hangup if the caller did not press # after the voicemail message

[bilal ghayyad]

Dears;

In FreePBX, when I select voicemail for the extension, and if the caller sent for the voicemail, and he leaved (or did not leave) a voice message, and did not press #, so the channel will stay open and this is not good specially if the call was coming from outside via the analoge lines (because the caller might hangup and the dahdi does not detect the hangup, so the channel will stay openned). 

How to let the voicemail hangup automatically after waiting for certain seconds (for example after 30 or 40 second), then to hangup or jump for the next line to run it? 

What is the parameter or the setting field in the freepbx that can resolve this (the voice mail message to be maximum for 30 or 40 second, after that to hangup even without pressing #). From where?

Regards
Bilal