wait, cant you use a C5 crossover at the ends of a 50' cable?
Just a thought, otherwise run a lot of c5 crossover cable and get some links..which cost more than the c5 cable i bought to do the same thing.
Cross over cables are made to connect end devices (PCs , Xboxes , Network HDD) and streight through cables are for connecting end devices to routers, switches and hubs.
He is going to need a crossover cable to connect his xbox to his pc otherwise he would use a streight though cable to connect the xbox to the router.