You probably haven’t tried to configure 3CX with Cbeyond’s SIPConnect service, as it’s not publicly supported yet. I’m testing a 3CX connection to Cbeyond’s SIPConnect  as a trial and here are my findings so far;

First of all, it was the simplest easiest SIP Conversion I’ve ever done. We were done in about an hour from start to finish. Keep in mind my 3CX system was already running, extensions were already setup, the only thing I didn’t have was a connection to the PSTN.

In 3CX you should see Cbeyond as a VOIP provider, if you don’t see this option, then first thing you should do is upgrade your 3CX to the latest version. Once you do that, you can use the wizard to add Cbeyond VOIP.

You’ll notice that the wizard auto fills in the SIP proxy addresses, these may be different for your area. Since this option is dimmed out, you need to leave the default addresses, click Next, then click Back, now you’ll notice they are not dimmed anymore! You can now enter the addresses you got from Cbeyond.

Follow the wizard providing your primary phone number as the authentication ID and username along with your Cbeyond provided password. Once configured, go back into the SIP settings for the connection you just created and make sure you have g.711 Ulaw codec selected.

At this point you should be able to register with Cbeyond. Once registered, if you are not able to make outbound calls but your call rules are setup correctly, go into VOIP provder settings and go into Gateway/Provider Outbound Parameters. Now change the “from: user part” to “LineNumber” external number of line. You should now be good to make outbound calls. Reasoning for this is, by default 3CX sends you extension to Cbeyond as the number trying to make the call, and as Cbeyond does not know or care about your local extensions, it denies access. Changing it to the external number lets the call go through.

I will be testing the system over the next few days and will report back. On a side note, sound quality is impeccable over SIPConnect.