[Asterisk-Users] Incoming Calls

[Rich Adamson]

> Here is where the problem is.
>  
> When the call comes in, it will be ringing on 2 of the FXO ports,
> and all the other phones in the office. I would like various / all
> the IP phones to ring, however asterisk must not answer the call 
> while that is happening or else the normal extension would not 
> continue ringing. Obviously when an IP phone answers it will then 
> pick up the call and connect the 2. Is this possible, or is this
> how it normally works by default?

Maybe. Part of the answer is dependent upon exactly how your existing
pbx handles the call.

The approach I'd use for testing purposes is _not_ to ring both
extensions to asterisk, but rather just one of them. When that
extension rings, asterisk's fxo card will sense the ringing and
the logic within your dialplan will have something like:
 exten => s,1,Dial(${PHONE1}&${PHONE2}) 
that will cause two sip phones to ring. You can add more sip phones
to that statement if you'd like. If one of those sip phones answers 
the call, the fxo port will go off-hook (to your existing pbx), 
causing it to believe the call was answered; the existing pbx analog
phones should then stop ringing.

If an existing pbx analog extension answers the call, ringing to the
asterisk fxo port will stop, and therefore ringing to the sip phones
will stop a few seconds later.

There will likely be a lag of time between ringing of analog phones
and ringing of sip phones (by one or two rings), which might be
somewhat disturbing to people that can hear both phones ringing.
Should someone answer an analog extension first and someone answers
a ringing sip phone seconds later, the sip phone user will hear
nothing more then dialtone (depending upon how much lag actually
exists). 

The above essentially says that one of the existing pbx to asterisk
fxo interfaces must be dedicated to your special ringing arrangement.