by Alex » Wed Feb 24, 2010 8:47 am
The Handy Tone 502 has its own built-in NAT-Router/Firewall.
If you are putting it behind your Com cast NAT-Router/Firewall, they may be blocking SIP and RTP ports required by the 502 to access VoIP ports over Internet properly.
Either put the Comcast router into DMZ mode to unblock ports for the 502, or study the Comcast router manual to see if you can "Port Forward" SIP ports 5060-5065 and RTP ports 10,000-20,000 (UDP).
Or, Remove the Comcast Router and replace with the HandyTone 502; the 502 has its own built-in Router, then your PC can be connected from output of the 502.