You need the following... Mini-DVI->DVI adapter (one should have come with the iMac) DVI-D->HDMI cable of the desired length. This will not transmit audio. TEG
I'm confused?! ---I didn't get one with my iMac. I checked apple website "Mini-DVI output port with support for DVI, VGA, S-video, and composite video connections via adapter---Adapters are sold separately."