Adapter is not useless, we used it many times in office splitting, all we had to do is cut 4 wires on a socket side to use with cat4+ cables

what about old adsl splitter?

Aren't many of the splitters just tiny hubs?

There are actually old proper Ethernet hubs from when switches were more expensive. They were used a lot in industrial applications because they were relatively low bandwidth. They did however use electronic repeaters instead of just tying terminals together. The downside is that without switching there was a lot of packets being destroyed by two devices transmitting at the same time.

Time ago I need one of this gadgets, and i could not afford a switch, not for money but because I didnt have enough power plugs… So I bought one that with a buton u can "switch" the signal to one or another end device, like how an electric switch works.

I like that device coz it dont need to be pluged to the power, dont has speed limitation, and wont stop working if both devices are open like the one in the video… Obviously it still not work for 2 devices simultanously… But for thoes rare moments when I need dat.. I still can use wi-fi in one.

It is a white cheap-plastic box with 2 butons (A and B) that cost 8 dollars/euros on amazon, but it is more reliable that what it seems at first look

I used splitters like these before. The ones I had to use had pinout diagrams on them. I used them for sharing a cable between a telephone line and a 100 mbit ethernet connection.That being said, if you have to use this in your job I would suggest looking for a new employer.

Technically you could use the splitters with selfmade patch cables that change/use the correct contacts for this method.
But a this point it's probably easier to buy a switch for one shared gigabit uplink or run a second cable for full gigabit for both devices, instead of using only 1/5 with this janky solution.

In what world is 100mbps slow?! As long as you are not doing crazy stuff like live editing files on a server from a client, 100mbps is completely fine. For gaming it's more often than not overkill and you can even stream multiple 4K video streams simultaniously (btw, according to the steam hardware survey, less than 5% of users even use a 4k display, whereas ~65% use Full HD – and that's gamers!). Most of the world would be happy to even have 100mbps. In my department, some of the more remote offices have 10mbps, and most of the employees don't even notice. Most of the building runs on 100mbps, and only a small few offices have 1gbps, and that's on an "on request"-basis. The process of applying for the faster connection is straight forward and fast, yet we barely ever get any requests for it, because, let's face it, 100mbps is more than enough for most applications.

I discovered the pin-to-pin wired splitters recently and they were actually exactly what I needed for a weird edge case: my solar inverter has an RJ45 port with RS485 serial on pins 4 and 5, an input pin for an overcurrent emergency stop signal on pin 6, and a common ground on pin 8. The serial port is normally unused outside of testing and installation, but I wanted to use a homemade serial device to monitor power output through Home Assistant, and still keep the original safety interrupt functional. I bought one of these splitters on ebay for £4 – couldn't believe it actually existed, for all the reasons you discussed in the video, but it was exactly what I needed and it works perfectly. It might not work for actual ethernet, but there are lots of weird non-standard uses for RJ45 out there where something like this might have a legitimate use.

I use something like this… female on both sides. I needed to extend the network cable my landlord had put into my living room without taking the cable out. And where the cable ends (above the door) I don't want to run an active device, not even the cheapest of hubs. The best I could find was a 1 in 2 splitter, with RJ45 sockets on both ends, plugged the landlord's cable into one side, mine to my switch on the other… My worry was that I'd encounter some signal drop due to shoddy quality, but it actually works just fine. I have a NAS and a Windows PC connected to this both of which get about what I can expect from my ISP.

Me who has 10mbps when Linus said 100mbps is kinda slow :
Bro this is so fast 💀💀💀

I think that the only purpose the scam splitters could be used for is very long distances, like this:

device 1 <–> splitter <—-2 cables—-> splitter <–> device 2

Linus using the rotary tool without a mask induces physical pain within my soul.

Can I drop ship these splitters with today's sponsor?

Such a fuckin scam sponsor Auto-DS

never thought I'd see a AutoDS ad here

…100MBit is slow? Oh.

Oh dang. We have 50. And those are a huge improvement over the previous 16 a few years ago.
Well, our digital infrastructure is fucked.

Or you know… just buy a small cheap reliable $10 switch that actually works.