[asterisk-users] QSIG transfer of calls away from Asterisk?

[Philipp von Klitzing]

Hi!

> Is it possible (a) in the QSIG protocol and (b) in the Asterisk
> implementation of it, to arrange it so that a transfer such as
> described above causes the call to revert back to being handled
> completely by the external PBX, and release the two B-channels?

The QSIG keywords that you are looking for a "call diversion" and most 
probably also "path replacement". 

In the Q.931 world there is "call diversion" for Point-to-Multipoint and 
"call reroute" for Point-to-Point connections. The bristuff patches come 
with call diversion, while chan_capi support has both (but that's 
depending on the ISDN card you are using); chan_sirrix also supports both 
methods, as well as basic Q.SIG features. 

In how far any of these - more or less fully - implement QSIG as well I 
don't know, however it appears that the Sirrix people would be ready to 
help if you pay them... ;-) And for what concerns chan_capi you might 
want to take a look at this:

http://www.melware.org/ChanCapiQsig

Cheers, Philipp