24U's Phone Companion is the only plugin I've heard of that handles PBX support.
Although depending on the APIs and other methods (IE URI scheme) different PBX systems use, other integrations may be possible.
There are hundreds of PBX systems out there, so it's impossible to say what's supported or possible.
If you are looking for assistance developing a solution around it, why not contact 24U directly? They do development and you could hire them to assist you in the integration of their product to your solution.
Thank you for your reply.
For what and 24U Software email I sent 4 for 1 1/2 months left unanswered, could you phone them
The purpose of this project is especially entering clasique telephone line and a PBX call
Have you ever carry out this type of project?
A good day to you