Hi All We came accross a typical problem, Let me describe you through SIP IP Phone -----------> SIP Proxy --------------> MediaGateway -----------PSTN Network IP address 'A' IP address 'B' IP address 'C' Phone No. 'xxxx' Now when we make a call from SIP IP Phone to a PSTN network say xxxx no (an IVR no.). call gets establish, but in the mean while if the network of SIP IP Phone goes down, call is still going on. Is there any method through which we can check if the IP phone is UP (on Network) or not, if not then call gets disconnected. Ritesh Jalan