but the "call forking" future is related to inbound calls, the pbx
fork the call throw sip and pstn in order to receive calls, right?
your first answer talk about the possibility to make outbound calls
when sip is not available.
so i can't understand if the "trigger callback" feature activate the
pstn line to receive inbound calls or with this feature i can switch
extension from SIP to classic and make calls even when sip is not
available.