I’m getting back into PC gaming again, a lot of good shooters coming out on PC lately. I have a ethernet cable going from my cable box to my Xbox in my “office” (I’m retired, so a game room, lol)… been using wireless for my PC since I’ve only really done SP gaming.
Can I buy, if they make them, a splitter and send a cable to both?
Thx.
No, ethernet cannot be split.
To do so requires a switch, and two more cables.
Cable to switch
Switch
Cable to device A
Cable to device B
Running multiple devices on one line leads to “packet collision”, hence a switch which acts like a traffic intersection / controller.
Small 5 or 8 port Gb switches, even with POE, are cheap these days.
ALL of this stuff is cheap these days, it’s incredible what you can buy on amazon or elsewhere for so much less than in the olden days, circra 2000… 
Unless you want a GPU, that is…
Wait, you do a trick that is not official but works very very well.
you have this:
Machine 1 - cable 1 - active network port 1
because your cable is passing from one place to other and you not want or can’t put a second cable you can do this:
machine 1 - adapter - cable 1 - adapter - active network port 1
machine 2 /… … … … … … … … … … \ active network port 2
where the adapters you use a female rj45 to split to other 2 males.
The trick is that tcp/ip in reality only use 4 wires, so the other 4 non used wires you can use to connect a second pc. the adapters what do is rewire in both sides to on the males sides use the correct pins and in the female side to use all 8 rj45 wires (4 wires pc1 and 4 wires pc2).
I can ensure that it works perfectly well even with cables + 100m and in Gbps.
What is important is you do the correct wiring. Search on the internet for this trick to see what pairs you should use and the scheme for the adapter home made.
Its a unofficial trick and works!
This is not valid as the signaling standard for Gigabit make uses of all four pairs (8 wires).
Two pair / four conductor wiring was the standard for 10 megabit and 100 megabit setups.
true, sorry, its max 100Mbps, anyway, if the ports are caped to that speed you can use that trick. if not, use a switch on the other side
Yeah, I think it’s $10 for a 4 port switch. Silly not to get one. You just need 3 cables for 2 devices. One to the switch and then one for each device.
small switches of 4 ports are super cheap, yeah and you have smart margin for mistakes. Because doing that adapters you can enter into electric problems if you wiring them wrong!
No offense intended, but that seems like a way to introduce new and interesting problems into your network, to the excessive chagrin of your IT folks…
Plus there’s the possibility of frying your network cars/motherboard ethernet ports, not to mention the possible consequences were POE introduced into the equation… 
Hey Magnum. Splitters for ethernet do exist and you can indeed use them. They’re unpowered as well saving you from having to need a free power plug. The disadvantage is that only one device can transmit over the cable at a time. If you only want to use either your PC or your XBOX at any given time, you will be fine. If you want to play online games on the PC while the XBOX does an update or the other way around you will need a switch as is recommended by others in this thread.
Thanks all, just a simple switch is all I need and will get.
LOL, be careful, you might trigger my PTSD!
Well hell, after ordering it next day from Amazon… my Razer laptop doesn’t even have a port, it’s only wireless. So this was all a waste, lol. But thx.
Back to amazon! A super cheap USB to ethernet adapter maybe? 
LOL, I feel your pain!
My wife brought home a DVD for some training course the other day…
…only for me to point out that we no longer have a disk drive in the entire house! 
I’ve got a pretty nice Dell laptop for work and it just comes with a dongle, which I’ve honestly never used. Cables are pretty much dead in my world to the desktop.
Thanks again for the advice… I did get a powered netgear switch, everything works great.
Funny thou, I question was it really all worth it, lol… my wireless speed for my PC and my console was 300 MB/s down, 10 MB/s up… since I hard wired they both have doubled, but really do I need that speed to game, hell I was playing the original Ghost Recon and Rainbow Six co-op on a 56 k modem, with no major issue. lol.
Oh well more speed can’t hurt. 