109: Which USB port is which? USB ports and plugs explained

Hey there do-it-yourself technicians. Today we’re talking all about USB. Where it came from, what it’s used for and which plugs are which.

Universal Serial Bus or USB was released in 1996, and it replaced a plethora of different plugs on macs and pcs including serial parallel the game or joystick port the apple desktop bus the ps2 port firewire and more.

The USB port was popularized by Apple when it released the Bondi blue iMac in 1998 as that was the only expandability port that it had so you had to use USB, it was the way of the future.

From there, manufacturers started making devices with USB, and the whole industry followed suit.

Speeds varied greatly over the years, with the original implementation only 1.5 meg and 12 megabit for high speed, but that was enough, initially, even the low speed was more than enough for mouse and keyboard communication, and the highest speed was enough to transfer data from things like flash drives and external hard drives which just weren’t that fast in those days.

As requirements have increased, so too has speeds, up to 480 megabits per second for USB 2 and then 5, 10 and 20 gigabits per second for USB 3 and 40 gigabytes a second for usb4.

The connector or plug has varied a lot over the years as well, starting with the ubiquitous standard USB plug. That’s actually known as the USB-A plug. You know the one, the one that you try to plug in but it doesn’t go in, so you turn it over and plug it in again, but it still doesn’t go in, so you turn it back the way you had it the first time plug it in, and it works. Annoying but true.

Interestingly I read an article just recently where one of the original implementers of the USB standard spoke up on the issue of reversible plugs. They tried to find a way to make it reversible, but there was no way they could do it without basically doubling the cost by doubling the amount of wires involved and making it all prohibitively expensive at the time. That said, there are newer cables that do actually manage to get reversible USB-A plugs to work.

There’s also the USB-A socket, great for an extension lead like this if your computer’s a little bit out of the way and you want to run a cable up to your desk.

Other standard plugs include USB-B that looks like this which you would use to plug into larger external hard drives, printers and other large devices. As devices started getting smaller we moved to mini USB that has the muffin shaped connector that looks like this. Next, we went much smaller again with micro USB the trapezium-shaped connector that looks like this.

These are still very common today on phones and drones and anything small that needs, usually power, from the USB. As we got the faster USB we needed the super speed connectors that look like this for the A and this for the B the only device that I have that uses this is an external hard drive dock so it doesn’t really get a lot of use. And there was a micro version of the same connector used in 2.5″ external hard drives.

More recently we’ve seen the release of USB-C the first truly reversible USB plug and a plug that doubles as USB connectivity and usually power connectivity as well in many modern devices, including the new MacBooks Chromebooks and many Windows PCs as well.

The last connector I’ll add to the list is the Apple 8 pin Lightning connector. Even though it’s a proprietary Apple connector it’s still very commonly used and worth knowing the name of.

Did you know that the colour of the USB socket on the computer is also important? Standard USB ports tend to have a black insert.

High-speed USB 2 and above ports used a blue insert, often with the SS designation for super speed.

Yellow USB inserts designate a port with sleep and charge that allows the port to provide power even while the machine is asleep. This actually means you could use a laptop with a yellow USB port as a giant battery pack if you really needed power for a device, even if you had the laptop completely off. That is of course until the laptop’s battery was exhausted as well.

For those that might find it useful I’ve created a reference poster that’s linked up here, that’s got all of the different common USB plugs and sockets their names and their usage. I hope you find that useful. Now that I’ve made it I’m going to have a copy up in my office so when somebody says I need the USB cable for my “thing” I can at least point it out and work out exactly which cable it is they really mean. Honestly, I swear I get asked that at least once a week.

You can of course get adapters between some of the different connectors. Something like this will allow you to plug an existing USB-A plug into a device that might only have USB-C ports like a new MacBook for example. Some of these can be really flimsy though so it’s worth spending the extra money to buy a good one rather than these one dollar ones that break very easily.

One final point is devices that handle multiple connections. this USB drive you can click out a USB-C at this end or, the other end you can click out a USB-A but, the top of the body pops up leaving a micro USB which you can see in more detail here.

This sort of thing is really handy if you’re moving stuff between different devices that have different ports in it.

Let me know in the comments down below if you learned something new from this video and while you’re there hit the thumbs up button as well.

The Tech Doctor exists to help you become your own technician and navigate your technology maze.

Thank you so much for watching and have a great day!

Download The Tech Doctor’s USB Visual Reference Chart here: http://techdoctor.com.au/USB_Visual_Reference_Subscribe

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