I have what I think is a simple question but difficult to write.
OK here goes:
from my router(linksys wrt54gl) I am running 1 cat 6 cable into a a room, now what I wanna know is there a device that will allow me to essentially split this one cable to 3 other cable like is this what a hub or switch would do??? I wanna split this one cable so that my PC, XBOX, and TV can have internet access instead of having to run 3 separate lines into this run.
Also one more question will there be a noticeable downgrade in speed if all 3 devices are leverage this one line at the same time.
Yes you need a switch. There shouldn't be any performance difference unless you manage to exceed the capacity of that single connection, which your average home network will probably have trouble doing.
It would work. A hub relies on shared bandwidth though as all the traffic is broadcast between all ports on the hub. Most people get the two confused, and these days switches are about the only things you can buy. Even some products labeled "hub" are actually switches. Switches are better in every respect and true "hubs" are all but dead in the market place... pretty much just a marketing term for "switch". :-)