No. I'd check that you have the right conductor pair on each contact. I'd also do a continuity check on all conductors. Worse comes to worse, I'd use two smaller cables and a hub in between.
I think you have a bad cable. Should be virtually no difference between a 10 footer and the 50 footer unless you have a bad driver on the network interface card. Can you try another long cable? Can you try another port on the router? And is that a standard 100BaseT interface port on the XBox?
Are you sure both cables are physically the same too, IOW one is not a crossover is it?
Go here, pay the $7.. and get it over with.
The 100m figure is for an active network — switches or hubs that are powered and repeating an amplified signal from one network node to another. Your router and XBox are nodes, and apparently they don’t have a strong enough signal to talk at 50 feet. Either that, or the cable itself is bad.
I’d try the 50ft cable between a PC and the router. If that works, then the offender is the XBox, since obviously the router is pulling its weight. If the PC doesn’t work, then it could be any of the three — the cable, the router, or the XBox. The only way to know would be to try a different 50ft cable, or put a quality switch in place — shorter cables from router to switch and from switch to XBox. Even a $20 switch should work fine: http://shop3.outpost.com/product/4774329
Basic troubleshooting Zen says, try another 50 foot cable. A new one.
Though, if you have a laptop, you could try hooking it up to that cable and see if it works, on the off chance there’s something wrong with the xBox.. xBoxes are known for having problems. Though my xBox (purchased on the first day of availability) has worked flawlessly.. and I’ve not heard of any problems with the NIC.. usually it’s the DVD drive..
In the absence of a hub, switch, or router a crossover cable may be necessary.
A time-domain reflectometer would be handy for testing that cable right now.
On a more practical note - for long cable runs where the wire is near an exterior wall - or running outside the house: if you live in a thunderstorm-prone area, consider installing Ethernet surge protectors at both ends.
I had some connectivity issues with my (original, not 360) Xbox a few years ago, when I did the exact same thing (ran a 50’ Cat5 cable rather than springing for the wireless bridge). I think it took the third cable I made for it to work well. There are differences in cable quality, but it could also have been something I did in making the cable, although I have a fair amount of experience making those cables.
I finally bit the bullet and bought a wireless bridge. I didn’t pay a bunch of extra money for the Xbox specific one; a generic wireless bridge worked just as well and you can find them for under $50, and probably even cheaper used. I don’t know how well they work with the 360 (if that’s what you have); my router is now next to my 360 and a 5’ cable works fine.
Your answer is here. ...somewhere.
Lol, cable trouble!
The Xbox uses an ethernet Physical Layer chip that might have holes in its cable length capabilities, specifically in their adaptive equalizer. I’ve seen the errata posted for those chips.
Test using 10BaseT on your router, don’t use the Xbox. If you can send data back & forth to your router, the cable is good. 10Mbit is more robust than 100Mbit ethernet.
If the cable works but not at the length you’re using, it will be cheaper to start cutting a few meters of cable and refitting the RJ45 — you were just going to throw the cable away, right?. Make sure you retest again on the router.