[Asterisk-Users] Wait for dialtone

[John Novack]

Rich Adamson wrote:

>>Is it possible after dialling a trunk prefix to wait for dialtone (or wait 2 seconds) before 
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>continuing to dial the outgoing number ?
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>>I need to "hunt" for one of several lines, and when one successfully provides dialtone, to continue dialling.. 
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>> 
>>A simple NO will do, but if there's a workaround, I have not found it. 
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>I don't believe there is any dialtone detection support in * today.
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>You can add a "w" in the dial statement for analog zap ports to insert a delay, but that delay does not involve listening for anything.
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>Each "w" adds about 1/4 second or so, something like this:
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>exten => _9XXXXXXX,1,Dial(Zap/4/ww${EXTEN}) 
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"w" doesn't work either when pulse dial=yes

Someone smarter than I about the source maintains that  some sort of 
tone detection is present , but not called.
I would assume from that , that either it WAS at some point and there 
was a problem, or they never turned it on and tested it.

One problem would be is the whole world doesn't use precise  350/440 
dialtone.

It is curious that really cheap modems have been able to do this now for 
years.

John Novack