[Asterisk-Users] Check for stutter dialtone on ZAP FXO channel

[Cameron Beattie]

<snip>
What it SHOULD do is, check the DC voltage on the line, and if less than 
8-10 volts, consider it BUSY/ unavailable/not connected, THEN check for 
dialtone before dialing. Also optionally listen for stutter dialtone before 
dialing, making the detection of stutter dialtone available for some other 
action.
<snip>

This is interesting. Does anyone have an example of how I can check the 
analog PSTN line for stutter dialtone and then perform an action based on 
that? What I want to do is check the PSTN and, if there's a stutter 
dialtone, dial an access code, record what is heard, play some DTMF, hangup 
and put the recording into a voicemailbox.

Any help would be appreciated.

Regards

Cameron