Can 3cx connect to another IP PBX? For example, using talkswitch? What we want to do is have a SIP extension in talkswitch which will become a trunk in 3cx. Is this possible? I tried to do this; via configuring a generic VoIP provider and connecting to talkswitch. The log on 3cx says "registration succeeded" but the trunk status is still colored red and says "not registered". just for testing, I tried the 3cx phone to directly connect to the talkswitch and it works. I was hoping that the 3cx ip pbx can connect as well. any thoughts? thanks.