LAN splitter adapter not working properly

[pennwooding]

I've just moved my BT router which means a couple of my LAN cables won't reach it. So I bought a two port RJ45 splitter adapter. So what I've done as I have LAN cable going into the back of my router. The other end goes into the single side of the adapter and I have the two LAN cables attached to the other side of the adapter. However, there is one problem, one both LAN cables which cater to individual computers are connected I don't have an Internet connection on either computer. If I disconnect one of the LAN cables then I get my Internet connection back. By the way, I'm not trying to use both computers online at the same time because I know that won't work. I just don't know why it works with just the one LAN cable connected but won't work with both of them. That's what the device is designed to do.

 

[velocityg4]

This is not what a LAN splitter is designed for. A splitter can only work with one computer at a time. It is a cheap outdated solution for when you move a computer around to plug it in at multiple location. Since switches are so cheap. Splitters have become largely useless.

What you want are couplers. Each line from the wall should have its own coupler. Then an Ethernet cable should be run from a dedicated port on the router to each coupler.

In this case that would mean using two LAN ports on the router. If you don't have enough LAN ports. You need to use a switch. Then you go Router > Switch > Each Coupler.

Coupler: https://www.amazon.com/Dinger-Coupler-Ethernet-Extender-Adapter/dp/B071NVVB6M/ref=sr_1_3?ie=UTF8&qid=1510177333&sr=8-3&keywords=rj45+coupler

Switch (if needed): https://www.amazon.com/TP-Link-Ethernet-Replacement-Unmanaged-TL-SG105/dp/B00A128S24/ref=sr_1_3?s=electronics&ie=UTF8&qid=1510177366&sr=1-3&keywords=switch%2Bgigabit&th=1

Update: If you want. You can plug each cable from the wall into the switch. Then just run one line from the switch to the router. You'd be replacing the splitter with the switch.

 

[pennwooding]

Yeah, I think you're right. All I need to do is extend the two LAN cables so they reach my router.

Thanks