Hello, I don't know much about cisco so any help is welcome. I have a 7920 Cisco phone and i connect it to my computer via a USB cord. My computer is unable to connect to it because i do not have the CD installation hardware or something to that effect. I was wondering where i could just purchase this CD and if i can't is there a place to download it so i can get my 7920 to start working?

that phone runs on the SCCP protocol which is proprietary to cisco, I doubt they even offer a sip firmware for that phone so you would have to have a cisco system to use it ..

Either you can use Asterisk or Call manager plus a switch for that phone.