I have a 7921 wireless ip phone. I downloaded and installed the 7921 usb install tool, followed directions exact, tried it on 2 different PCs, it wont connect or even ping the phone at designated ip 192.168.1.100. Is there another method? the only missing instruction was the default gateway, but I expect that isnt needed if all on same net. They had a contractor setup their cisco system but no notes or howtos.