What does "Allow External/Anonymous INVITE's" mean in my dashboard under SIP users and/or numbers?
What is a user?
What is RTP?
What is SIP ALG?
What is SIP?
How can I set up a SIP trunk on a Grandstream UCM hardware PBX using a username and password?
What's the difference between SIP trunks and SIP users?
How can I set up a SIP trunk on a Grandstream UCM hardware PBX using an IP address?