what is dvi?

Digital Video Interface i think.

I think this is what HDTV is sent over. DVD players dont do HD signals yet...

the only purpose i see for them is on the reciever for video switching, the HDTV tuner, and the HDTV

I could be 100 wrong on this though.

I believe DVI is for digital video.

DVI started out as a way of digitally connecting a computer video card to a digital TV monitor, such as a LCD flat panel monitor. Now DVI is being incorporated into satellite boxes, TV's and DVD players

The DVI connection allows transmission in the "digital" format from your source(Sat/Box DVD/player)to your TV.

There is 2 version of the DVI connection, an early (or First version) and a revised version. You "CAN NOT" mix and match You must use the first version source with a first version TV and a revised version source with a revised version TV

HTH Dave

DVI stands for digital video interface.
Davehrab is right there are two formats that are not
compatable, HTMI and HDCP.
The interface will carry an audio signal as well.
We cant get a standard for anything!