No one in their right mind can argue that the emergence of USB is bad. Before we first got our iconic USB port, the world was filled with awkward, incomparable connectivity standards.
A typical PC of the early 90s had LPT, Serial, PS2, SCSI, and MIDI ports. And these are just a few of them! We now have universal serial bus , but it’s not as versatile as one might hope!
USB Versions and Speeds
It is important to understand that while the two USB ports and cables may look the same, this does not mean that they have the same capabilities. This is because USB standards have improved over the years. The equipment that sends and receives information is faster, and the internal wiring is significantly different.
And yet the key part of USB is the “universal” bit. In practice, this means that if the USB cable is plugged into the port, it will work. The worst that can happen is that it defaults to the oldest and slowest standard that both devices can understand. This means that some devices will simply not work properly because they cannot transfer data over the cable fast enough.
When you buy a USB peripheral, it will list the highest standard it supports and sometimes requires. This means that your computer, cable and device must comply with this USB standard in order for them to perform as best as possible.
There are three generations of USB devices right now, the fourth of which has yet to be released but in development. This is the least you need to know:
- The maximum theoretical speed for USB 1 is 12 Mbps (megabits per second). These older devices will work with modern USB ports, but not faster and usually at a lower speed. It is also called “full speed” USB, which can be confusing.
- USB 2 is much faster, with a maximum theoretical speed of 480 Mbps. The marketing name for USB 2 is â€œHigh Speedâ€.
- USB 3 is the most recent standard at the time of writing, with a theoretical speed of 5 Gbps (gigabits per second). Its marketing name is “SuperSpeed”.
USB 1.1 is in fact the most widely adopted USB 1 standard, with virtually no USB 1.0 devices ending up in the hands of users. USB 2.0 received a single revision, but for USB 3, most of the fixes worked with USB 3.1 and 3.2.
They are further separated into generations. USB 3.1 is subdivided into Gen 1 and Gen 2. USB 3.2 has Gen 1.2 and 2×2.
Generation versions actually vary significantly in performance. USB 3.1 Gen 1 runs at 5Gbps, but Gen 2 is twice as fast! USB 3.2 generations operate at 5.10 and 20 Gbps respectively.
Note about Thunderbolt 3 over USB-C
Thunderbolt 3 is a completely separate standard for transferring data over USB. However, it uses the same USB-C port! It’s not as confusing as it sounds, so let’s figure out what you need to know:
- Any USB-C device will work with any Thunderbolt 3 port.
- A Thunderbolt device won’t will work with a regular USB-C port without Thunderbolt.
- Thunderbolt USB-C ports often have a small lightning bolt icon next to them.
- USB-C cables work like Thunderbolt cables, but cheap cables may not support speeds as expected.
- Thunderbolt cables work just like USB-C cables.
Thunderbolt is a nifty technology, but this article is about USB, so we’ll stop there.
USB port types
Now that we’ve covered the different generations of USB, let’s talk about real physical ports. However, before we do that, let’s make a quick tip – the USB 3 ports inside are usually blue! This makes it easy to distinguish them from older types of USB ports.
The original USB port is known as a Type A port. This is the type of port we all know and love, found in everything from flat panel TVs to clock radios. The USB 1 and USB 2 Type-A ports have only four pins inside. Two for data and two for power. USB 3 Type-A ports have a total of nine pins but are fully backward compatible.
Next, we have the less common type B port. They usually appear on devices such as printers or external hard drives. This is a female port for devices that are not “host devices” like a computer. USB Type B 1 and 2 ports are not physically compatible with Type B USB 3 ports.
Finally, we have the final Type-C port. This tiny, tightly wired port is reversible. This means that, unlike type A or B ports, you can insert it however you like. With an adapter, it is compatible with all USBs except USB 1. It replaces other connection types from USB 3.2.
These are the so-called “standard” ports, but there are “mini” and “micro” versions for devices that are too small to handle the full-size USB-A ports. Game controllers, smartphones and other small devices can have mini and micro versions of Type A and Type B ports. There are also Type-AB ports for devices that act as a host and a peripheral.
Before USB-C ports, Micro-B ports were most commonly used in smartphones. Mini-B ports can be found on devices such as the PlayStation 3 controller.
While Micro-B ports are still widely used for smartphones, powerbanks and most modern small electronic devices, USB-C is fast becoming the new standard for every USB device, regardless of size.
USB Power Standards
USB is more than just a way to transfer data between devices. It is also a way of transferring power. With the exception of Apple mobile devices, almost every modern smartphone uses a USB port of one type or another for both charging and data transfer.
In fact, many devices that don’t transfer data at all still use USB for charging. One example is batteries for small toy drones. Some USB cables carry only power, no data wires. The power cables that come with power banks are sometimes of this type.
It is actually very useful to use the power cable only to prevent viruses from infecting mobile devices. For example, at airports where chargers can be provided, hackers can replace them with devices infected with malware. The so-called “data blocker” USB cable prevents this particular vulnerability.
As far as the actual power that comes from the USB cable, there are many options. One thing you should know, however, is that if you plug a USB device into a USB-compatible port, it will draw as much power as it needs, or as much power as the port can supply, whichever is less.
This way, you don’t have to worry about connecting your phone to a charger with more power than the one included. If both the devices and the cable are from well-known manufacturers, you have nothing to think about.
What’s important to know is that some USB power supplies don’t charge or power your device well. USB provides power depending on the equipment generation. USB 1.0 and 2.0 provide 500mAh current. USB 3.0 can supply up to 900mAh of juice. USB 3.1 can provide up to 3000mAh (3A)!
These are simply numbers that a manufacturer must adhere to in order to meet certification minimums. You’ve probably noticed that car chargers and chargers for Apple iPads are often rated at 2.1A, which is not part of the USB specification. To use the extra power available, the device needs to communicate with the charger to agree on how much power it needs.
If not, the default will be the minimum, which is usually 500mAh. All you need to know is that the charger and device must support the same “fast charge” standard that must be transferred over and above the USB specification.
Apart from the high power of the latest USB 3 versions, all other fast charging standards are not industry standards. Thus, there is no guarantee that your â€œfast chargingâ€ smartphone will charge at maximum speed from a third-party charger.
For example, Android phones usually display a notification about whether the device is charging slowly or quickly, as well as the estimated time.
Using USB on a Mac
USB has been a feature of Apple computers almost since USB itself existed. The first iMac of 1998 dropped all but two USB ports and two FireWire ports. It’s no exaggeration to say that Apple has played a big role in USB adoption.
Modern Macs have also done something radical when it comes to USB technology and have ditched ALL ports in exchange for one or two USB-C ports. This means that if you want to use any device that doesn’t natively use USB-C, the only solution is a USB-C hub.
The good news is that USB-C has so much bandwidth and power that the addition of an inexpensive hub can give you any connection you want. Be sure to find one that has been specifically tested for Mac compatibility. MacBooks with two USB-C ports can work with so-called dual-hub devices, which plug into both USB-C ports and combine them for use with a hub.
One final note on USB 4
Before closing the book on USB, we need to briefly talk about the future. USB 4 is just around the corner, so it’s a good idea to prepare for it. This new standard supports bandwidths up to 40 Gbps, but is only backward compatible with USB 3.2 and USB 2.0.
In practice, this hardly bothers anyone, since all USB 1 equipment is already practically outdated. The current USB-C port will be the mainstay of USB 4, so all USBs are unified, so concerns about whether different ports will work together are a thing of the past. So in just a few years, you won’t have to remember everything you read in this article.