asterisk users - Apr 2005 - Check for stutter dialtone on ZAP FXO channel

<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

> 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.
I'm about 90% sure the drivers for the digium x100p and TDM card
never made use of those chipset values for DC voltage, etc. In fact, 
Mark implemented a piece of code over six months ago to simply detect 
if a pstn line was attached, and he had to back that out for some 
reason. He left it in ifdef's at the time.

Not sure about tones though. Best guess is that its not in there.