USB is one of tech's ultimate success stories - a universal standard that took off in every way. But things have got a little confusing over recent years with USB 3.x having multiple cable types.
There have also been several connectivity standards within and alongside USB 3.2, for example.
This will be fixed with USB 4.0, which will use one standard connector and bring the multiple connectivity standards together. Here's what's happening and why.
The history of USB so far
1995 - USB 1.0 debuted and could transfer 12 megabits. USB 1.1 followed and could also work with older devices. The familiar USB connector was introduced.
1998 - The iMac G3 is the first mass-market PC to bin serial and parallel ports in favour of USB.
2000 - USB 2.0 enters the fray, offering some power delivery options (the forerunner to the standard that enables you to charge your phone). USB flash drives debut.
2008 - USB 3.0 makes its debut, with a 5Gbps transfer speed. USB 3.1 is introduced as an upgraded version.
2014 - USB-C or USB Type-C makes its debut. This uses USB 3.1 tech, but with a new connector designed to take over from old-style USB ports. Like Apple's proprietary Lightning connector, it's symmetrical and can be inserted either way up.
2017 - USB 3.2 is first talked about, offering data rates of up to 20Gbps. It'll be introduced this year (2019) but it's not as simple as it seems for, like the Wi-Fi Alliance, the guys behind USB have decided that the old standards will be renamed as well.
- USB 3.2 Gen 1, formerly known as USB 3.0, with speeds of up to 5 Gbps.
- USB 3.2 Gen 2, formerly known as USB 3.1, 10 Gbps top speed.
- USB 3.2 Gen 2x2, which is actually "proper" USB 3.2,” with up to 20Gbps.
Yes, we're not making this up, so expect to see USB 3.2 a lot this year.
2019 - USB 3.2 will be introduced to products on shelves, while USB 4.0 has now been announced - read on!
The Thunderbolt confusion
One of the further confusions recently has been the Intel-designed Thunderbolt fast data transfer tech that was initially deployed by Apple. It works over the USB-C connector these days (although previously worked over DisplayPort before USB-C was common). Although many PC manufacturers now produce devices with Thunderbolt, there are two key issues:
Firstly, not all devices have it and unless you've got the spec sheet in front of you, it's not really clear what devices do and don't support it. That's because the USB-C port can be a Thunderbolt port, but it can also be a standard USB 3.x port.
Secondly, the same devices can have ports that are Thunderbolt compatible and some ports that aren't Thunderbolt compatible - even though they look the same.
There are currently more than 400 PCs on the market with Thunderbolt 3 as well as 450 compatible peripherals.
So what's happening now?
Intel has announced that it has essentially contributed its work on Thunderbolt to the USB Promoter Group - the industry body that decides what the USB standard should mean.
That means that Thunderbolt will basically underpin USB 4.0, so all USB 4.0 devices and ports will be automatically compatible with Thunderbolt devices for super-fast data transfer as well as device charging and display across a single cable as now. The USB 4 specification is soon to be released.
Device makers will be able to make Thunderbolt devices without paying royalties to Intel, which should make adoption easy.
Intel previously said it was planning to integrate Thunderbolt 3 into future Intel CPUs beginning with Intel’s upcoming 10nm processor codenamed Ice Lake.
Speed freaks will be happy
“The primary goal of USB is to deliver the best user experience combining data, display and power delivery over a user-friendly and robust cable and connector solution,” said USB Promoter Group Chairman Brad Saunders in a statement.
“The USB4 solution specifically tailors bus operation to further enhance this [by] enabling the further doubling of performance.”
Yep, double the performance (40Gbps) compared with the fastest version of USB 3.x which offered 20Gbps. However, there is a bit of a sour note becuase that's exactly the same speed as Thunderbolt 3, meaning that there will be no enhancement for current Thunderbolt 3 devotees on a standard that will be several years old already.
Existing USB Type-C cables will be able to transfer through two lanes, whereas if you have compatible certified cables, you'll be able to transfer up to 40 Gbps.
USB 4 release date
The USB 4 specification will be published in the middle of 2019 and will probably appear in devices in late 2020 or early 2021 - it usually takes around 1.5 years for devices to come to market once a new standard is published for the first time.
Over 50 companies are currently involved in the standard, especially those behind the USB Promoter Group - Apple, HP, Intel, Microsoft, ST Microelectoronics and Texas Instruments.
What will happen to the connector?
The USB-C connector was designed to be future proof and reversible. It will be staying. The new standard will be backwards compatible with existing USB 3.2, USB 2.0 and Thunderbolt 3 hosts although if they don't have USB-C connectors they will need an adapter.