(Pocket-lint) - USB is one of tech's ultimate success stories - a universal standard that has been the centre of wired data and power transfer for 20 years now.

But things have got a little confusing over recent years with the USB 3.x standards having multiple cable types. That's been made more confusing by having multiple connectivity standards as part of this, too. 

This will be fixed with the incoming USB 4.0, which will use a single standard connector (USB-C) and bring multiple connectivity standards together.

It's supported inside Intel's 11th generation Core processors as well as Apple Silicon Macs starting with the MacBook Air, MacBook Pro 13 and Mac mini. 

The USB 4 specification was published in late 2019 and so the time is right for devices to appear with it - it usually takes around 18 months for devices to come to market once a new standard is published for the first time. Over 50 companies are currently involved in the USB standard, especially those behind the USB Promoter Group - Apple, HP, Intel, Microsoft, ST Microelectoronics and Texas Instruments. 

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. Just like the Wi-Fi Alliance did before it, 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 over the coming months. 

2019 - USB 3.2 will be introduced to products on shelves, while USB 4.0 was announced.

2020 - USB 4 is supported in Apple Silicon Macs as well as Intel's 11th generation Core processors. 

The Thunderbolt confusion

One of the further confusions over the last few years has been the Intel-designed Thunderbolt fast data transfer tech that was initially deployed by Apple. There are now more than 400 PCs on the market with Thunderbolt 3 as well as 450 compatible peripherals. 

Thunderbolt works over the USB-C connector these days (although it previously worked over DisplayPort before USB-C was common). But Thunderbolt has two key issues: 

Firstly, not all devices have Thunderbolt 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 or - now - USB 4 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. So...

Putting Thunderbolt into USB 4

So to make things simpler Intel announced that it has contributed its work on Thunderbolt to the USB Promoter Group - the industry body that decides what the USB standard should mean. 

That means 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. 

Device makers will be able to make Thunderbolt devices without paying royalties to Intel, which should make adoption easy.

Intel is also integrating Thunderbolt 3 into Intel CPUs now, an effort that began with Intel's latest 10th generation Core processors in 2019.

Intel

The slight caveat to this is that Intel has now announced a Thunderbolt 4, which is very similar to Thunderbolt 3 but it supports at least dual 4K displays and PCIe data speeds up to 32 Gb per second as well as transferring data at high 40GB per second speeds over a cable up to 2m. If your device has Thunderbolt 4, it will definitely also support USB 4. 

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.

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 backward compatible with existing USB 3.2, USB 2.0 and Thunderbolt 3 hosts although if they don't have USB-C connectors they will, naturally, need an adapter. 

Best laptop 2021: Top general and premium notebooks for working from home and more

Writing by Dan Grabham.