Grandstream UCM6104 IP PBX and Nexvortex SIP trunks expert needed.
The Grandstream UCM6104 is an Astrisk based IP PBX appliance. We need a system review for best practices.
We are having an issue with dropped calls or calls not going out or in on first dial. We are on the beta .42 version of firmware because of another issue.
We have the phone behind a Cyberoam firewall on it's own LAN one.
MUST have experience with Grandstream.