why haven’t USB cables replaced every other cable, like Ethernet for example? They can transmit data, audio, etc. so why not make USB ports the standard everywhere?
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For the full features of the USB 3.1 standard the maximum cable length is 1 meter.
Imagine if you will a corporate office, cubicles filling the floor, a server room with racks of machines, and you can’t go more than one meter before having a powered repeater of some sort.
Really sounds like a job for Ethernet doesn’t it? In fact there are various standards and cable/ports which are better for different applications. Just because USB C can do something a bit doesn’t mean it can do it as well as everything else. A moped can move people and cargo but it doesn’t mean a moped is good for any time you need people or cargo moved.
The cable composition isn’t as relevant as the ports they’re plugged into. A network port has all kinds of engineering history behind it which makes connecting your computer to a community of other computers a lot easier.
USB is a very short-range standard, and the standard doesn’t really lend itself to multi-node networking. It’s very much one-to-one connectivity.
Lots and lots of reasons, usb isn’t designed to be a networking cable.
Range – depending on which flavour of usb, the maximum cable length is single figure meters, by comparison Ethernet is 90m.
Cost – you wouldn’t just be replacing cables, you’d be. Replacing billions of £££ worth of network infrastructure the world over.
Protocol – usb isn’t designed for networking, tcp and udp are the most prevalent protocols in use on networks, they’re optimised for its use. Then you’ve got addressing and routing concerns. Usb just isn’t designed to deal with this in a large scale standardised way.
Ever hear the phrase “Jack of all trades, master of none”? USB is sort of like that. USB is exceptionally useful because it covers almost every need. Clear exceptions to this are monitor ports and network ports, because USB isn’t quite up to the task.
There are USB to ethernet adapters, and USB to video adapters. Newer standards like Thunderbolt 3 have essentially replaced traditional docking stations with external bricks with a bunch of ports. The average user might not notice the limitations of any given peripheral standard, but in a bigger setting, the limitations become more apparent, and purpose-built standards are used instead.
It is also worth noting that USB is not merely a cable and port. It is a chipset.
Ethernet can push similar speeds (10Gbps) over an inexpensive eight strand twisted copper cable up to 330 feet (100 meters). It’s also very simple to run and terminate.
Lots of good answers here explaining differences in protocols and cable types used for USB and Ethernet. But let’s assume we would keep the same ethernet cables and same ethernet protocols, just replace the connectors to be USB (and as a clip-in mechanism, as someone suggested). There’s another reason why that is still a bad idea: voltage.
PoE (Power over Ethernet) is designed to deliver 50V, which would likely damage any USB device you would accidentally plug in into it.
Now, you used Ethernet just an example, but generally your question was why we don’t make the same connector for everything. Imagine that every port at the back of your PC is exactly the same shape, including things that carry a 120-220V power supply. That would just be calling for disaster.
Where is the actual ELI5?
It’s somewhat analogous to the idea of “If a Bugatti is the fastest car, why aren’t all cars Bugattis?” Or the somewhat opposite idea “If a semi-truck can carry more cargo than any other road vehicle, why aren’t all road vehicles semi-trucks?” At the end of the day, nothing can be best at ALL things.
USB does best at connecting a bunch of (relatively) dumb devices to a single host (your computer) over a very short range. It’s been updated many times over the years. It started as a simple way to let you have input devices send some basic data (like mouse movements, keyboard presses, etc.), then grew to allow (relatively slow) bulk data transfer from storage devices. In more recent years, it’s improved the speeds for that bulk data transfer, AND started to add real capacity to send significant power for charging portable devices. That it can do all of this means there are compromises in all those areas. Yeah, it’s fast enough for your thumb drive, but it pales compared to your m.2 NVME SSD. Yes, it can charge fast, but is still far slower than dedicated LIPO chargers (like what are used in drones/RC hobby stuff.) And with the right cables, you can even get a few meters of distance in the cable, but that’s far, far short of the hundreds of meters you can do with ethernet, or the kilometres you can do with fiber.
At the end of the day, all computer data is just ones and zeros, “binary” as we call it. Morse’s original telegraph from 1838 used dots and dashes… binary. You CAN literally send a tiktok over a telegraph wire. But you shouldn’t, because there are better options. But the point is nearly any data interconnect can nominally do the job, and thus it’s easy to see where your question comes from. Yes, any data you push through Ethernet or HDMI could theoretically go through USB as well. But there are times where the trade offs aren’t worth it, financially or otherwise. It’s way cheaper to buy a 300m fiber cable than to put USB repeaters and power supplies every 3m.
The tl;dr is when you want to go fast, you use the sports car, but when you have a lot of cargo you get a truck. And if you want to have fun off road, you get into rally racing and AWD compacts. And that’s not even taking into account the people that want to cross the sea or fly into space. 🙂
Ever tried to use a swiss army knife to undo more than one screw? And then used a cordless drill?
A multi tool is great for doing a lot of stuff somewhat well, but a dedicated tool does one thing great.
Same with cables, there is always a balance of size, data speed, current and price.
Having lived through the absolute mess of 90s computer cables, I am perfectly happy having three data cables. USB, HDMI and RJ45.
USB-C is replacing most other cables: power, video, previous USB versions (which themselves replaced half a dozen different interfaces).
Networking is difficult because it needs to work at kinda high speed, over a medium distance. USB needs to work at extreme speeds over a short distance, but also needs to be cheap enough (in low speed versions) to e.g. put it in a $6 mouse. It’s hard to design a system that does all that, and you’ll have to make compromises somewhere.
Network cable standards are also much older than USB (not just USB-C). Replacing building wiring is not likely to happen, so we stick with what exists. There is just not enough reason to change it, design new switches, etc. Maybe it’ll happen some day. It should be possible to spec USB4 in a way that it can work with 100 m cables.
These different cables existed because back then they were the first to solve a specific problem, and there was little benefit to reusing e.g. the video connector for something else because you’d then have two identical looking but incompatible ports. USB works because a lot of companies agreed on a standard, and then added features until it covered almost all use cases.
Do you have any other cables (except network) in mind?
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