I have a Polycom SoundPoint IP 501, and I can't seem to make it work correctly. I get a dial tone, but get no sound in or out. I've also tried a grandstream phone, but I run into the same problem. I use a linksys wrt54g router. I have Qwest DSL. I'm on vonage for my home phone system, and it haven't had any problems. How can I hook into my companies 3cx system with either the Polycom, or the Grandstream (preferably the Polycom).