call.recall() blind transfers the call to us again. Blind transfer works in such a way that the client at the other end of the call hangs up this call and then calls the address provided instead. In this case, as the provided address is our address it will make the other end hang up and then call us again. We automatically answer the new incoming call, thus the end result is that call.recall() makes a recall by the other end of the call.
call.recall() will fail if other end of the call does not support blind transfer.
None.
Nothing.