Working ethernet splitter

Does an ethernet splitter work?

TL; DR. Buy a switch. NEVER use ethernet splitters.

Midlan posted a link to this schema:

"Wired in parallel" means that if you are using a device like this you will get a lot of packet collisions at best because you are connecting the two TX pins (pair 3, pins 1 & 2) of the computer (jacks 1 & 2) and the RX (pair) together have wired 2, pins 3 & 6) pins together. Ethernet cabling

Twisted-pair Ethernet, 10base-T, 100base-TX, 1000bast-T, etc. all need to be connected end-to-end. At each there is a transmit (TX) and a receive pair (RX). This is how a crossover cable works.

The simplest Ethernet network using twisted pair media uses a crossover cable between two computers:

As you can see, Computer-A's TX pins are connected to Computer-B's RX pins, and Computer-A's RX pins are connected to Computer-B's TX pins. (For simplicity, I didn't wire up pins 4, 5, 7, and 8, but for completeness they should wire directly over pins 4 through 4, 5 through 5, etc.)

You just add one next to it so that the pins on Computer B&C are wired together (pin 1 to pin 1, 2 to 2, 3 to 3, etc.). In the best case scenario your devices won't work, in the worst case scenario it will damage your ethernet ports.

Computer-A can be a hub or a switch, but the problem remains that the TX and RX ports are connected to and from each other.

Here is a circuit diagram for a simple (passive / currentless) ethernet:

Ethernet is a digital signal and not like an analog phone signal where you can use a splitter to add another extension. Each small wave pattern is a packet of information transmitted by a TX port that is supposed to act as an RX port. Wiring TX ports leads to all sorts of weirdness.

Instead of a splitter, your best bet is to add a mini switch. However, if you already have several other switches on your network, you need to be careful with your cabling topology.

There were other search results where the two unused pairs (1 and 4) on 100 Base-TX were mapped to pins 1, 2, 3 and 6 on the second port, so you had to use those devices on each end. However, the Ethernet cable protocol was designed to use twisted pair cables so that there is elimination between the cables. Start doing non-standard, non-compliant things and you will end up with non-standard, non-compliant, unexpected results.