I'm passing my TV input through my computer so that I can use the video stream in an application I'm creating which then outputs to my TV.

E.g. Sky Digibox/FreeView box -> Laptop -> TV

Where on my laptop I'll be using the stream in a WPF application so I can overlay XAML objects onto it.

My question is, what would be the best way for me to send the signal back to the box to say change the channel for example? I don't want to have to use the remote, I want the computer to handle everything. Is there a standard cable these boxes have that could take what would normally be a remote control signal and use that as input instead? Or would I have to go down the route of looking at some sort of Infared LED to send the signal recreating the remote?

Apologies if this is not clear enough, let me know and I'll try and be more precise.