[VoIP] Ringing multiple devices

[John R. Covert]

This was "Early audio aka non-sup call progress info" but really
is a completely different topic.

>Can you use this technique to receive CID

No need for any of the "Progress()" stuff or the ",noanswer" on Playback
for CID.  CID is there as soon as the first step in your dialplan is
activated (except on some PRI services, where it may require a delay
of about a 10th of a second "Wait(0.1)").  SIP sends the CID in the
INVITE message (the first message received), and ZAP FXO ports do not
activate code in the dial plan until the CID is received or until
the second ring if nothing gets sent by the CO.

>pass the CID out to another extension

When ringing a single extension, the received CID will be passed on
automatically.  But it sounds like you have your large display on
its own FXS port with nothing else connected.

In Asterisk, the Dial command can ring any number of devices.  The
first one to answer gets the call, and the others stop ringing.  This is
done like this: Dial(SIP/dev_1&SIP/12345678901 at provider&IAX/iaxstuff,120).
That will ring the specified local SIP device (or IAX, or ZAP) and the
phone number given via the provider, and everything specified.  Any
off-line devices or busy devices are ignored.  You can even use the
dial plan by using the local device: local/extension at context, and if
that dial plan code has, for example, a 15 second delay followed by
its own Dial command, Asterisk will ring the other things in the first
Dial command first and if none of them are answered, continue to ring
them but after 15 seconds begin to ring the destination in the local
context.

Since CallerID will be sent out to everything you pass the call on
to, as long as the incoming trunk provides it, all you have to do
is include the device with the CID display in the dial command with
any other station(s) you're ringing.

/john