why can’t an Ethernet splitter be used without UN-splitting back the connection at the other end ?

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When [googling “ethernet splitter”](https://www.google.com/search?q=ethernet+splitter&tbm=isch) intuition immediately tells that you can have one input (where the cable coming from the router enters) which can be split to 2 computers at the other end.

However, this is not how it works:

>To use splitters, you’ll need two: one to connect your two devices, and another at the other end to “unsplit” the connection. This means you’ll still be using the same number of Ethernet ports on your router as if you were using two separate cables. You don’t add any Ethernet ports by using a splitter, you simply share a single cable.

(source [https://www.howtogeek.com/797864/ethernet-splitter-vs.-switch-whats-the-difference/](https://www.howtogeek.com/797864/ethernet-splitter-vs.-switch-whats-the-difference/))

**QUESTION**: why isn’t the signal simply **split** ? What is it that a switch does differently ?

In: 1

If an Ethernet splitter is used, the connection needs to be UN-split at the other end in order for the device to work properly.

Those devices take advantage of that 100 Mbps ethernet only uses [half the wires](https://o.quizlet.com/uJPiue-vL4u2QnPsga3RRg_b.png) in the cable. So you can use an 8-wire ethernet cable to carry two connections that only actually need 4 wires each.

It’s a stupid idea in this day and age. Gigabit and above require all 8 wires for a single connection. Just buy a dirt cheap gigabit switch on each end. You can get those for about $10.

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When you look at a cable like a basic Cat-5 Ethernet cable what you’re really seeing is a collection of 8 smaller (colored) wires all bundled together. Each of those individual wires connect to a pin in the terminal clip that you plug into the Ethernet port and hardware at both ends are expecting certain data from that pin. A lot of uses for the whole cable only uses 4 of those wires. So basically your splitter is separating those pins into two sockets, and you need a splitter on the other end to make sure the data from each wire goes to the right place.

It’s much like an 8 lane interstate highway. A bunch of cars coming from different places but going the same general direction for a while merge onto the highway. But they all eventually have different destinations so they need to be split back off into separate roads.

Ethernet is point to point. A cable has 4 twisted pairs – 8 wires.

In connections less than 1GbE only 2 pairs – 4 wires are used. 2 wires for sending, 2 for receiving.

The splitters let you utilize the 4 unused wires on the cable, but still need a dedicated port to connect to.

1GbE uses all 8 wires and as such you couldn’t successfully use a splitter.