Wired Remote

We're using the Dell 1209S DLP Projector, the laptop which controls the presentations is in the back of the room, about fourty-fifty feet behind the projector, and the IR remote does not reach that far/the receiver is infront of the projector.

I've searched high and low, and yet, have been unable to find anything about a wired remote for this projector. I found something about the mini-DIN RS232 control from PC but haven't seen any documentation on that "feature".

Why do I need a wired remote you ask? The presentator needs access to blank the projector screen without walking back and fourth disturbing everyone.