May 15, 2017

USB – A History: Evolution from USB A & B to USB Type-C


USB-C has gained considerable traction since it was first released two years ago. It is the go-to connector for most mobile phones, tablets and even laptops, today. The only exception is Apple’s Lightning connector – but even Apple has adopted USB-C for its MacBooks.

To better understand USB’s current evolution to Type-C, it’s important to go back in time and see where USB started.

USB Type-A

A very, very long time ago, USB started with Type-A, which is most familiar to any person on Earth. It’s the easily recognizable flat rectangular shape. Type-A is the original design for the USB standard, one that continues to survive today.

Of course, Type-A has been upgraded, all the way from 1.1, 2.0, 3.0 and 3.1 today. USB Type-A is backwards compatible so 3.1 works with 2.0 and 1.1.

As the most numerous of all USB designs, you can find it everywhere. Cables are one object, but desktops, laptops, flash drives, wall chargers and car chargers and a sleuth of other devices use Type-A.

USB Type-B

Enter the B. Type-B came into the scene and changed things. On one end (male side) is Type-A and on the other end (female side) is Type-B. Type-B came with several new designs, often creating confusion. Out of five common designs, only one remains most popular: Micro-USB.

It’s the most prolific of USB Type-B ports, found on any smartphone and tablet that isn’t an Apple device. Its small design meant it was perfect for compact devices and the design allowed both charging and data transfer ability.

Micro-USB once reigned as prince of USB design, but its days are coming to an end. USB Type-C is quickly taking over the throne.

What about…?

Is Lightning and the 30-pin connector considered a USB design? Yes and no. On one end, the proprietary design belongs to Apple, but the USB end is still USB Type-A.

The updates in USB

As USB designs changed and technology pushed forward, revisions were made to bring better functionality. USB 1.1 came out in 1998 and was only able to provide data transfer at speeds of 12Mbps. Then in 2000, USB 2.0 introduced charging capability and provided a mind-blowing top speed of 480Mbps data transfer.

It wasn’t until eight years later when 2.0 was upgraded to 3.0. USB 3.0 crashed through the gates with a theoretical transfer speed of 5Gbps – 10 times faster than its predecessor. Ports and connectors are colored blue to differentiate them from 2.0.

The 3.x confusion…

USB 3.0 is a worthy upgrade, but then the USB Implementers Forum – the group responsible for the development and certification of USB products and standards, decided to rename it 3.1 Generation 1. It’s the same thing as 3.0.

3.1 brings us to 3.1 Gen 2

This is now the era of USB 3.1 Gen 2. It doubles the speed from 5Gbps to 10Gbps, but also increases max power output to 20V-5A for a total of 100W. Enough to charge Macbooks and other laptops, this new iteration of USB brings with it the Type-C connector.

USB Type-C

Still backwards compatible with all USB types (you’ll need an adapter, though), the Type-C connector is a massive upgrade. No more flipping and turning the connector type this way or that way to squeeze into a port; the connector is now fully reversible like Apple’s Lightning connector.

Type-C also revolutionizes the USB world by making many of the connector types we use today – obsolete. USB-C (a.k.a. Type-C) provides audio, video, power and data transfer all into one connector. It’s no wonder new mobile devices and laptops are choosing to become slimmer at the expense of losing bulky legacy ports.

The ability for USB-C to deliver 100W of power means laptop AC chargers are a thing of the past. All it takes to charge laptops like the Macbook Pro is a USB wall charger and a USB Type-C 3.1 Gen 2 cable. Those same accessories can then be used to power a smartphone or tablet as USB-C automatically adjusts the amount of power delivered by detecting which device it is connected to.

One Port and Connector to Connect them all

For consumers, USB-C is a connector of convenience. Not having to fumble around with three different USB-B cables for three different devices and not having to carry around a 3.5mm audio cable, an HDMI cable and a power cord is a blessing in disguise. Just one cable replaces all the former connector types and their respective cables.

Yes, it’s true there are not that many USB-C devices out there. Companies continue to make Micro-USB and legacy port devices. As with all new technologies, early adoption is a slow but steady process.

However, it is a guarantee that USB-C will be the connector of the future. Apple’s Thunderbolt 3 connector uses USB-C and Intel claims it has developed a USB audio standard to make the 3.5mm audio jack totally obsolete. These are two tell-tale signs of the C revolution.

To learn more about USB-C and what it replaces, read our previous blog post.

By masy@eeco Blog Technology explained Share:

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