Outbout FAX during voice call


Is it possible to make an outbound FAX transmission during a voice call?

The case is the following:

  1. The IVR (Asterisk) calls a customer (so this is an Outbound call).
  2. The customer interacts with the IVR using DTMF and selects several items from a menu.
  3. Now, when the customer finish with his selections, on the same call, I would like Asterisk to start a FAX transmission with a report of the customer’s selections. The receiver, as soon as he hears the FAX tone coming from Asterisk, switches his device to FAX.

Is this possible? Can I initiate a FAX transmission in the middle of a voice call? Can the receiver switch to receive a FAX (I think this is possible)?

It is important to do everything on a single call, otherwise, of course, I can make a separate outbound call just for the fax transmission, after voice call completion.

Thank you!

This is possible with the help of the “h” extension.

It is not possible with the “h” extension, as “the same call” has hungup at that point. He’s not asking for a call back, but for the current call to switch from voice to fax mode. I don’t know the answer, for Asterisk, but the “h” extension is not it.

Yes, the h extension would come into play if the call is hung up after the caller “finishes” with point 3 of the use case. Which I think would not be a problem.

The h extension cannot process any media.

The important phrase is “in the same call”. What the OP means is not finishing the call, but simply finishing the speech part of the call.

If you used h, you would need to originate a new call, and the caller would need to hang up to receive it. That might end up with the wrong end bearing the phone charges, although this actually only seems to involve outgoing calls, which rather weakens the case for using one call, especially as someone really has to want the faxes if they don’t hang up immediately on getting an incoming IVR call and are actually prepared to cooperate in selecting the faxes and putting the fax machine into fax mode.