Smartvox UK designed and maintained bespoke VoIP solutions based on OpenSIPS. One example was a project to create a Microsoft Teams SBC which integrated via Direct Routing handling inbound and outbound calls. It was a multi-tenant solution.
Unfortunately, we no longer offer support for VoIP infrastructure because the owner, John, retired in 2022. However, the web sites are still being maintained.
OpenSIPS is a highly efficient SIP Proxy, Registrar and SBC. Want to know more about it? click here.