Everything you need to know about USB Types

I bet almost all of you have never seen any of these weird, rare USB connectors before, but by the end of the video, you’re going to be a complete expert. And there are several more where these came from.

USB types

First, as a little bit of a background, USB connectors are going to be mostly categorized in three different ways: by size, type and speed. I’m mostly going to focus on size and type today. For type, there are three. There’s A, B and C, and for the longest time, A and B were the only two, but more recently there’s C. And you probably familiar with these, the standard-sized Type-A and B here. And also Type-C, there’s only one size of it.

But speaking of size, there are three possible sizes right now. So it’s the Standard size, Mini or Micro. And the examples here are the Standard one you already saw, as well as, for example, Mini-B and Micro-B. You’re probably familiar with these, but here’s where things get a little bit interesting because probably the only Type-A connector you’ve seen is the Standard size Type-A, but there are other size Type-A connectors; just like there are Mini-B and Micro-B, there are other sized Micro-A, as well as there being some other random proprietary USB type connectors that are really only used by a couple of manufacturers. And you’re going to see all of them today.

USB Types Explained

Now, before getting into more detail about all the weird connectors, I do want to give some context and explain what this whole Type-A and B thing is so you’ll better understand the purpose of these connectors.

You see, unlike other data connection cables and interfaces like ethernet and HDMI, those are bi-directional. It doesn’t matter which side of the cable you plug into which device, because they’re both on the same side. However, USB is directional. There’s always going to be one device which acts as the host and the other device, which is just the device. I’ll call those things the connected device to keep it less confusing.

This distinction is important because when the USB spec was created, it was designed such that the host device is always going to be providing power to the connected device. Therefore, you needed to make sure that two host devices could never connect directly to each other on the same line, because then they would be providing power to each other on the same line and potentially fry things out.

So they created different physical plugs for both hosts and connected devices, and these are the Type-A and Type-B connectors. So the host device always gets a Type-A connector while the connected device always gets a Type-B connector. And with this, every single USB cable should have a Type-A connector on one side, Type-B connector on the other side, so that you can never connect two host devices together.

Of course, yes; there is the newer Type-C, which does have bi-directional power. You can plug it in no matter what way you want. But as you probably experience, almost all the times you have a host device it’s usually a computer. And in every single case, basically, it’s going to have a Standard size Type-A, just one size, but the Type-B connector might vary in size; it might be a Standard B or Micro or Mini-B.

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There is one exception to all this, though, which is the USB On-The-Go spec, which does have adapters that allow something like a phone to act as a host device and connect to another phone. But that’s something I’m not going to really get into. I’ll maybe mention it later.

Common USB Quick Summary

All right. So now that we understand types A and B, let’s get into all the different connectors and ports. And we can just very quickly go through the really common ones you’re already familiar with. Like you’ve seen, there’s the Standard A and B size connectors, and then there’s the Mini-B and Micro-B connectors, which just go into smaller mobile devices or whatever. For USB 3.0, things change a little bit.

The standard A for USB 3.0 is basically the same looking, whereas the B is just a little bit bigger. There’s also the Micro-B for 3.0, which is longer than a Standard Micro-B. But fun fact: the USB 3.0 ports are actually backwards compatible with USB 2.0. For example, if you take a Micro USB 2.0, you can actually plug it in to the one side of the USB 3.0 Micro-B port. And the same goes for the Standard 2.0 B connector; it can actually go into a 3.0 B connector. Obviously, it’s not the other way around because the 3.0 plugs are bigger, but that’s just cool to know.

Rare: Mini-A and Micro-A

Anyway, so those are all the common plugs and ports. Now let’s get into the rare ones that are the most interesting. So, first up we have the Mini-A plug. So again, remember, this means it would be used on a host device.

A Mini-A plug is actually deprecated, which means that it shouldn’t really be used in any new products or anything. You’re never going to really see this anymore. This one kind of does look pretty similar to a Mini-B, just a little bit differently shaped. Now, next up there’s the Micro-A connector.

Now, unlike the Micro-B connector, this one is actually a perfect rectangle. It’s the only other connector that’s a perfect rectangle besides the Standard A, and this one kind of looks like a shrunken down Standard A connector, almost. And actually, interestingly, this Micro-A connector is not actually deprecated. It theoretically could be used in some devices, although I think it is very rare, but it is still in the USB spec, the latest one. You can read it in there. It’s just not really something I’ve ever seen.

Mini-AB and Micro-AB

Now, here’s a couple of really interesting ports, because we have A connectors and B connectors but there are actually a couple AB receptors that accept both of the same size for each type. For example, there’s the Mini-AB receptacle. This one is actually deprecated; it’s not really used anymore. It’s replaced by the next one we’ll talk about, but basically it accepts both a Mini-A and Mini-B connector.

This one was actually really hard to find because apparently it’s really only used on mobile devices and not really used in cables. So I was only able to literally find the connector piece, but you can still see how it accepts both a Mini-A, when I plug it in here. You see? It goes in. And when I try to plug in a Mini-B, it also goes in here. And the purpose of this was for that On-The-Go feature of USB that I was talking about before.

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Basically, it allowed both A and B because sometimes you might want to use whatever device as a host, even though it was a mobile device, and other times you would use it as a connected device. Next up, though, there’s also a Micro-AB port, which like you probably guessed, accepts both Micro-A and Micro-B connectors. You can see here, I’m plugging in a Micro-A, and it goes in, and for the Micro-B, it also goes in right there. Now, interestingly though, the Micro-AB port is not actually deprecated. You could theoretically see this on a device somewhere. I personally have not seen it anywhere, but again, it’s possible.

Mini-A Port

So next up we have the Mini-A port. This one is apparently extremely rare, and it is deprecated so you’re never going to see it on any new products. And this is actually the only one that I could not get my hands on. I did order it from a specialty website but they canceled the order, so I think they didn’t actually have it. So I’m assuming you really can’t get it anywhere anymore. It would look like this, though, and the reason I think it is deprecated and doesn’t exist is because the Micro-AB port basically serves the same purpose. You can still plug a Micro-A just into the Micro-AB port, if one has that, which is not deprecated.

Non-Standard USB Connectors

All right, now we can move on to some rare, non-standard USB connectors. These are, from what I understand, not anywhere in any official USB spec, but they’re mostly just made by individual companies and used only in certain products. The first of these is the Mini-B 8-Pin connector, and this is, again, proprietary. It’s definitely used by some Nikon cameras, and apparently also certain Panasonic and Pentax cameras.

I think they’re all just old ones. For example, there’s the Nikon UC-E6 cable, which does have this connector on it. Now I should point out, I’m not actually even sure if this is really technically a Mini-B connector, anyway, even though I’ve seen it called that everywhere, because this doesn’t even fit into a Mini-B receptacle. So I don’t really know, but just interesting.

Next up, there’s also a Mini-B 4-Pin connector, which also kind of looks pretty unique. Apparently, this one is also used by certain specific devices like Casio, Fujifilm and Toshiba cameras. They’re pretty rare, I guess, so this connector is even more rare. And again, even though this is sometimes called a Mini-B connector it does not fit into any Mini-B receptacle at all, so I don’t know what the deal is with that.

USB “Type-E” Connector

All right, moving on. The next really uncommon connector I want to talk about is called, apparently, a USB Type-E connector, and it’s used basically only for USB 3.1. I keep saying apparently because I have not actually seen this Type-E named anywhere in the official USB spec, so I don’t know if the type-E is just kind of a nickname or what, but basically this is only going to show up on the internals of a computer.

So I’ve seen motherboards that have this Type-E connector on it, and again it connects USB 3.1 from the motherboard on to some external port, such as a front panel for USB 3.1 or potentially a USB 3.1 expansion card. It seems to serve a very similar purpose to the USB 3.0 20-Pin connector, which you can see here. And this is actually a adapter from this Type-E to a 20-Pin. So again, I’m not really sure how official this one is, or maybe it’s just a proprietary one invented by certain motherboard manufacturers, but still kind of wanted to point it out.

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Dangerous USB Cables

All right. So we’ve gone over all the different connectors and ports but I do want to talk about something very interesting, which are non-standard or “dangerous” cables. Like I mentioned before, there’s never supposed to be any kind of cable that has a Type-A connector on both sides, but obviously that doesn’t mean that it’s physically impossible for such a cable to exist. And actually they do exist.

For example, like this one. It’s a USB cable that has a Standard sized, Type-A connector on both sides. The reason it’s a so-called dangerous cable is, like I alluded to before, if you plug this into two host devices it could potentially fry things out because both are going to be sending power on the same line and neither is going to be expecting it. It could really mess things up. So you should never actually use one of these cables and plug it into two things; it could really cause damage potentially. Obviously, the fact that this cable exists means that it probably does have some purpose, but it’s probably proprietary and used in very specific, special circumstances.

But you’re never going to see this used on any kind of consumer device, because it could potentially be dangerous if the user went and used the cable on something else. I’m not sure if there are any other dangerous cables like the Mini-A to Mini-A or something like that. Those are already such rare connectors that probably there’s not going to be any cables made by that. So just the standard A to A is probably the only one you’re going to see.

Secret USB Pro Tip

All right, now, finally, for those of you who have stuck around this long, I want to give you a life pro tip that is probably the most important life pro tip you’ve ever seen. Which is how to always plug in a connector for USB the correct way.

You see, actually in the USB specification it says that the logo on the USB connector should be on the top facing up when you plug it in. And if the USB port is vertical, the logo should be facing the left. And even if the connector doesn’t have a logo on it, like it’s a USB drive or something, you can tell which is the top and bottom because the bottom has that split down the middle; then the opposite side is the top.

From my understanding, not every manufacturer actually does honor the specification, but at least now you know that the first way you should always try to plug in a USB is with the top side facing up, which is the side with the logo. And hopefully, that’ll save you hours over your lifetime of trying to plug it in the right way.

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