I am really new to 3CX and has limited knowledge in VOIP. We have a freeswitch in production connected to an E1 gateway that we want to interconnect to 3CX to allow intercommunication. I am unable to do it. - I tried to create a generic sip provider in 3CX using a sip extension created in freeswitch with no success. - I tried to setup a bridge using 3CX as master, put an username and password in a sip extension create in freeswitch with no success. - In my freeswitch, i tried to create a sip trunk using an sip extension created in 3CX with no success. I am stuck and if working will help me a lot to test it. What is the basic thing i can do to make it work. I should say that firewall check is not passed (in the forum, seems it should passed). Could someone point me in the right direction? I am able to connect the 3CX with an online provider for usa calls and to connect it to my E1 gateway as sip. Unfortunately, my E1 can only register with the freeswitch ip, so to test pstn calls i have to unplug my freeswitch and connect the 3CX to the E1 (with same ip, sip username & password). I am wondering as it is easy for me to connect the 3CX to online provider and E1 gateway, is there a software or sip service i can use to be in the middle of the 3CX and freeswitch. in this case, the 3CX and freeswitch will use this as sip trunk. My E1 gateway should be able to do this but needs to be reset as acl permits only to connect to ip freeswitch (cannot use this option). It is very frustrating. I need some help.