Hello, i have exactly the same problem, and i tried to disable the turn off wait feature in the modem properties, but that did not solve the problem. Call is hungup inmediately :
01:05:38 Call 101 -> sip:923109876@lacuna1
01:05:38 Incoming Call from: Carousel on Line: Carousel FXO Gateway
01:05:38 Dialing number: 923109876
01:05:38 Incoming SIP call
01:05:44 Answering call...
01:05:44 Call 101 -> sip:923109876@lacuna1 answered
01:05:44 Joining Lines...
01:05:44 Call from Line 923109876 to bridged successfully
01:05:44 Call has disconnected
01:05:44 Call 101 -> sip:923109876@lacuna1 disconnected
Help would be appreciated. Thanks for your help