We are looking to hire an expert individual or company to develop an open-source multitenant IP-PBX solution for 10-30 PBX (scalable to 200 in the future).
Ideally we are looking for a solution that will use FreePBX and a billing solution like A2Billing. Other alternative solutions are welcome, as soon as they are open source.
We are looking for a stable working solution (with no virtualization if possible) and redundancy.
Please bid only if you have relevant experience.