The ABCs and 123s of USB
The Universal Serial Bus, or USB, has been around since the late 1990s. What promised to be a universal solution for connecting computer peripherals has splintered into a bewildering alphanumeric soup. Not only are there different connector ends, but there are also different transmission standards. Trying to figure out what is USB has gotten a lot more complicated.
But if you’ll hang onto these two simple facts, you’ll be able to decode what’s going on:
A letter refers to the type or shape. A number is the technology speed.
Combining the two together is not consistently done, which adds to the confusion.
So, let’s break things down and untangle the nomenclature.
USB types
The USB types are straightforward. And with the release of USB Type-C, a consensus has developed on how to write them. These are the most common:
USB Type-A, USB Type-B, USB Mini-B 4-Pin, USB Mini-B 5-Pin, USB Micro-B, and USB Type-C
Of course, you’ll see them written a variety of ways, often without the word Type, with and without a hyphen, and “USB” placed at the end rather than the front. So, it’s important to focus on the letter.
Here are 6 USB connector types charts so you can view things up close. You’ll see the different ends as found on cables as well as what the various ports look like. Images are courtesy of Cables to Go.
1. USB Type-A:
USB Type-A is the standard connector that’s been around from the beginning. It tends to be the common end on a lot of cables that plug into computers or AC charging adapters, with the other end a different type. And it’s the one we all have trouble plugging in on the first try because it only fits one way.
2. USB Type-B:
You can find USB Type-B connectors on many printers, scanners, projectors, and even external hard drives. They are not as common today and may well be phased out.
3. USB Mini-B, 4-pin version:
4. USB Mini-B, 5-pin version:
Micro versions are more common than Mini-B. But you still might find these on cameras and MP3 players.
5. USB Micro-B:
You can find these on many portable devices, especially for charging those built-in batteries. However, we’ve noticed a trend here at Petra where many new devices now use USB Type-C.
6. USB Type-C:
USB Type-C is the latest USB connector type, and everyone loves it. It’s small yet there’s no squinting or flipping it over to insert it correctly. It is rapidly becoming the connector of choice and may truly become universal.
Cables have two ends
Don’t forget—cables have at least two ends. But their item names rarely include both ends. Usually, the other end is a USB Type-A. But that’s not always the case. So, if something is labeled USB Type-C, it may or may not have Type-C on the other end.
If you are trying to help a customer with a cable, be sure to find out what’s needed on both ends.
USB speeds
USB speeds are the other part of the “What is USB” story. These are the numbers often found in item names or specs for USB ports, devices, and cables. They are also called USB standards, USB versions, USB data transfer rates, or USB specifications.
As might be expected, speeds have gotten faster to better serve the demands of the increasingly sophisticated devices they feed. Unlike types, speeds must also worry about backward compatibility. Remember that the true speed of a cable is only as fast as the lowest common denominator in the hardware. So, a USB Type-C port built back in 2008 simply doesn’t have all the special innards that can handle the faster speeds developed later. It will still work, just not at top speed.
Here’s an overview of USB standards, logos, all connector types they work with, and transfer speeds:
Information courtesy of Tripp Lite
Most of us have heard of USB 2.0 and the various USB 3s. USB4, sometimes written as USB 4, is the latest, released in 2019. Unlike earlier speeds, it only works with USB Type-C connectors.
With faster speeds come cable length limitations. The specifications set by the USB Implementers Forum for all USB standards prior to USB4 call for a length of 3 meters or 9.8 feet. USB4, however, is .8 meters or 2.6 ft. This means that if longer lengths are needed, it is highly recommended that an active cable or powered hub be used. If a length exceeds the spec, speeds may well slow down.
For those still running USB 2.0 generation hardware, Everyusb.com states, “The cable length of USB 2.0 devices can be up to 16’5” at a maximum.”
Color coding
By the way, device ports are often color coded to indicate what kind of USB speed it supports. But color is NOT mandatory. The chart below from Tripp Lite shows the suggested color schemes:
What about USB Power Delivery and Video Delivery?
Some USB cables are charging only. Others are data only. While yet others combine both functions. So, if a cable is labeled sync and charge, it can certainly do both. If it says charging, then it’s probably just for charging. If it doesn’t state, it’s probably for both, but needs further investigation. USB Type-C cables should do both.
Reviewgeek.com digs more into the Power Delivery (PD) side of things when it comes to USB standards.
“USB 2.0 supports 2.5W charging and USB 3.0 supports 4.5W charging. To put things in perspective, 10W is enough power to slow charge your phone, and 18W is enough to fast charge your smartphone or power a Netbook or similar bare-bones laptops.
“In contrast, USB PD can handle up to 100W, which is powerful enough to power things like a MacBook Pro, monitors, docking stations, and most TVs. It can also fast-charge smaller compatible devices like your phone or Nintendo Switch. PD also only provides the necessary charge to your device but won’t overcharge it. Newer battery banks are starting to support USB PD, which are more capable of keeping your power-hungry devices powered and fully charged.”
USB Type-C PD is also bi-directional. For example, this means your customers who have Type-C smartphones and laptops can charge up from each other.
Video delivery is also important. USB Type-C cables are now being used to connect monitors thanks to video Alternate Modes. Certain ones can even support 4K resolution! All this depends, of course, on which USB standard is in play—and whether the Type-C port has been configured to handle those video Alternate Modes. Modes include Thunderbolt, DisplayPort, HDMI, VGA, Mobile High-Definition Link, or VirtualLink.
So, what is USB?
USB is a combination of shape and standards protocols. And it’s ever evolving. That’s why, to be more accurate, this blog should be called the ABCs and 1234s of USB.
Will there be a USB Type D? So far, only as an April Fool’s joke! USB Type-C, whose specifications were released in 2014, is the go-to shape for quite some time.
But you can count on the standards to get faster and faster. Whether it’s a variant of USB4 or a whole new standard remains to be seen. But given the lag between the development of a standard and it being used in the real world of devices, cables, and ports, it probably won’t be soon.
Interested in learning more about all things USB and the interplay of connectors and standards? Check out this informative link from Tripp Lite.
If you’re looking for a source of USB cables, take a look at our huge selection. If you’re looking specifically for Type-C cables, check out our subset here.
And for ways that Petra can help you grow your business, visit our special customer page. It is designed for retailers, etailers, installers, and upfitters interested in finding a wholesale supplier. One who can not only fulfill product needs but also partner with you to deliver strategic business solutions.