I am new to VoIP. I acquired several SPA504G phones and a 2811 router. I want to setup a basic VoIP lab environment with this equipment. I have interface Fa0/0 on the router connected to a basic 8-port switch, and a couple of phones connected to the switch. I eventually got an extension number assigned to both phones, and I get a dial tone on both phones. Since I'm new to VoIP, I'm pretty sure I missed some configurations, but I don't know what. Both phones have 1 line. Phone 1 has extension 1001, and phone 2 has extension 1002. As I mentioned, they both connect to a basic switch. When I try to call extension 1002 from 1001, and vice-versa, the phone says "Invalid Number." The running configuration of my 2811 router is attached. I would highly appreciate assistance, since I cannot figure out what I'm missing. Please be as specific as possible, since I'm not too familiar with VoIP configurations.
