Hi all, I call outbound gateway using following dialstring: sofia/outbound/9122@192.168.1.29 here 192.168.1.29 is any SIP provider (e.g. asterisk) In case when the number 9122 is not registered on that provider, so provider hangup with SIP response "503 Service Unavailable". Now my query is that how to detect this sip response at our freeswitch side. And What if there is no response at all. fyi: I am using javascript for processing the calls. Thanks MSP