Re:Without background processes, VOIP not so much. (Score 1)

Random musings on the possibility that the iCall s/w induces redirect behavior during call-setup (w/ the caveat that I'm assuming Iphone/AT&T uses the standard GSM stuff)...

I'm not sure of the date on this document (GSM Air-Interface), but see table 7.7 (Call control) where I don't see anything in the messaging that looks like a redirect message during call setup.

If you look at this ISUP docs you won't see anything there either. ISUP/TUP/etc are pretty basic call setup once the endpoint is known. Usually MAP/TCAP is used by the originating entities to do more sophisticated stuff (like finding the ultimate terminating endpoint, whether an artefact of call-forwarding, ported number, wireless roaming, etc.)

Now, ISUP is just call setup, and there's more in-call functionality (like sending DTMF digits, putting call on hold, etc) in the call control of the Air Interface. But, if ISUP doesn't support it (on the MSC->BSC interace) then it's not surprising that the Air interface doesn't either.

Ergo, even assuming the ability of iCall to interfere w/ the IPhone GSM stack behavior, no obvious ability to redirect an incoming call at the terminating point during call-setup. So, not betting the farm on that possibility.