[Asterisk-Users] Analogue call answer detection

[Tim Robinson]

Hi Tony -

I am needing the same thing.  In short, the answer is no.  the only way 
you can reliably detect answer supervision is :

1) Line reversal from the telco or PBX.  I think BT will provide 
reversal on answer if you request it as some payphones need it.

2) Meter pulse.  This starts from the point the call is charged, i.e. 
answer supervision.  BT charge an arm and leg for this and they are 
phasing it out anyway as payphones rely on built in tariff tables and 
line reversal.

3) Our old friend ISDN.  Perfect.

for busy, busydetect=yes is pretty good on analogue lines.

In the mantime you can use the c option in the Dial command to force the 
user to answer the call by pressing the # key.  There is a new feature 
request http://bugs.digium.com/bug_view_page.php?bug_id=0002356 that 
relates to this to play a message rather than silence to the called 
party to indicate that some action is required on their part to accept 
the call.

Rgds
Tim
Basingstoke

Tony Mountifield wrote:

>I've just been doing some tests using the manager API to originate an
>outgoing call via a X100P and connect the call to an extension:
>
>Action: Originate
>Channel: Zap/1/01234567890
>Context: local-extensions
>Exten: 6000
>Priority: 1
>
>I've noticed that extension is getting called as soon as the outgoing
>call has been placed, rather than when it is answered.
>
>Is the X100P capable of detecting when the call has been answered?
>If not, can the FXO module for the TDM400P do so?
>
>What about detecting busy or congenstion?
>
>I'm on a BT line in the UK, if that is significant.
>
>I will soon be doing the same thing over a T1 or E1 line instead. Can I
>be sure that answer will be correctly detected in that case, and that
>the internal extension won't be called until that happens?
>
>Cheers
>Tony
>  
>