Being the ultimate media center console of his generation the original Xbox missed one feature: the ability to power up the console from the IR remote. Many solutions were available on the market, one of them was the Xerc: a small pcb with IR receiver you should mount inside your Xbox. This mod was available on Sickmods, with full schematics and documentation. Sickmod is gone :-( so you will find all the info available on that site to build your own Xerc2.
From the now defunct site description: