asterisk users - May 2004 - Dial to Answer -- Can this be done?

Let's suppose you have a PSTN line with multiple extensions. One of these 
extensions is connected to an Asterisk FXO port. For reasons that I won't 
go into, the "normal" configuration of the system is that when a call
comes
in on the PSTN line, Asterisk *does not answer* -- the other extensions do 
whatever they would do if there were no Asterisk system there.

When I hear one of these extensions ringing, I want to be able to dial an 
extension on the Asterisk phone system that will allow the Asterisk FXO 
port to answer, and from there on Asterisk takes the call.

Any thoughts on how to do this?

-Thanks, Jim

Quoting Jim Rosenberg <jr@amanue.com>:
> Let's suppose you have a PSTN line with multiple extensions. One of
these
> extensions is connected to an Asterisk FXO port. For reasons that I
won't
> go into, the "normal" configuration of the system is that when a
call comes
> in on the PSTN line, Asterisk *does not answer* -- the other extensions do 
> whatever they would do if there were no Asterisk system there.
> 
> When I hear one of these extensions ringing, I want to be able to dial an 
> extension on the Asterisk phone system that will allow the Asterisk FXO 
> port to answer, and from there on Asterisk takes the call.
> 
> Any thoughts on how to do this?
Having several phones in parellel with an FXO line in * may be a problem
if you plan on making outgoing calls though this interface. If you will only be
dealing with incoming calls, I believe you would be fine. 

In * you should be able use a pickup group. 

I'm sure there are others who know more and can correct me on any
misinformation. Otherwise, I hope this heads you down the right road. 

Don Pobanz
> -Thanks, Jim

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> -----Original Message-----
> From: asterisk-users-admin@lists.digium.com 
> [mailto:asterisk-users-admin@lists.digium.com] On Behalf Of 
> Jim Rosenberg
> When I hear one of these extensions ringing, I want to be 
> able to dial an 
> extension on the Asterisk phone system that will allow the 
> Asterisk FXO 
> port to answer, and from there on Asterisk takes the call.
> 
> Any thoughts on how to do this?
By this I assume you mean that Asterisk won't acknowledge the call, nor will
it ring any internal extensions (eg: exten => s,1,whatever).

Let's assume we have extension '8701' to pick up the line, you could
try:
exten => 8701,1,Dial,Zap/1/

That works fine here using it to give direct access to the line's dialtone
on an X100P. I don't see why it wouldn't work if the line was already
ringing (but I haven't tried it).
> -Thanks, Jim
-Shaun

At 7:20 PM -0400 on 5/15/04, Jim Rosenberg wrote:
>Let's suppose you have a PSTN line with multiple extensions. One of 
>these extensions is connected to an Asterisk FXO port. For reasons 
>that I won't go into, the "normal" configuration of the system
is
>that when a call comes in on the PSTN line, Asterisk *does not 
>answer* -- the other extensions do whatever they would do if there 
>were no Asterisk system there.
>
>When I hear one of these extensions ringing, I want to be able to 
>dial an extension on the Asterisk phone system that will allow the 
>Asterisk FXO port to answer, and from there on Asterisk takes the 
>call.
>
>Any thoughts on how to do this?
>
>-Thanks, Jim
The answer to your description is "No, I don't know how to do
that."
It may be possible, since the chipset on an X100P or other Tigerjet 
chip _might_ be able to look at line voltage without actually seizing 
the line, at which point it might be possible to detect a pickup 
event somewhere else on the loop, which in turn then might be able to 
activate a "silent pickup" which could listen for DTMF.

However, I doubt that is feasible unless you really want to dig into 
the Zap drivers and/or the code logic on the Tigerjet chips.

A more reasonable way to do it would be to buy a TDM4xx card from 
Digium, and put one FXO and one FXS interface daughtercard(s) on it. 
Run the line from the phone company into the FXO line.  Create a 
dialplan that pushes any inbound call on the FXO directly out to the 
FXS.  I am guessing (though I don't know for sure) that it will not 
pick up the FXO until the FXS is answered.  At that point, you can 
manipulate the dialplan with the # button (yuck - see my previous 
rants on why Dial needs to be extended to do more stuff with 
single-digit keypresses, but that's another story.)

JT

> -----Original Message-----
> From: asterisk-users-admin@lists.digium.com 
> [mailto:asterisk-users-admin@lists.digium.com] On Behalf Of 
> Jim Rosenberg
> When I hear one of these extensions ringing, I want to be 
> able to dial an 
> extension on the Asterisk phone system that will allow the 
> Asterisk FXO 
> port to answer, and from there on Asterisk takes the call.
> 
> Any thoughts on how to do this?
I just read through your post again and believe I misinterpreted it the
first time. I assume you want to dial an extension to make * pick up the
call and send it into a context/extension.

If that's the case, I don't know. JT's post provides some more
insight :-)
> -Thanks, Jim
-Shaun