I have a office Inter-Tel VOIP phone that works on the office network fine. What I need to do is set the phone up to work from an employess house. Our phone server has a public IP address, which I reprogrammed the phone to look at instead of the internal remote ip. How ever the phone doesnt connect and give me and error of "local ip card addr invalid". The employee has a Cable modem. I was able to get this working before with DSL, but never tried it with a cable modem.