I have a free line from sipgate, works great, I don’t use it for outgoing calls just use my mobile, like the answerphone bit that forwards messages to email
I installed a kit recently without problems at set up other than not having the latest version of monitor so the keypads showed up as isolated but worked fine. Thought the reading of fobs a bit slow on set/unset though
We have an Avaya ip phone system, we have analogue and sip trunks into it with voicemail, call forwarding etc.
I trialled Sipgate a few weeks ago and that worked really well but didn't quiet meet our needs.
Whats involved with 3CX, is it difficult to set up etc, don't have much time at the moment to mess about
Ours are also cqr contacts and several times they have gone into tamper when they open the sectional doors, have replaced one three times, we have three other doors at the same site and not had any problems with them