The History of USB Standards and Transfer Speeds

USB (Universal Serial Bus) has become a vital connection standard for electronic devices today. From smartphones and laptops to digital cameras, USB is now essential for data transfer and charging.

Over the years, the USB standard has evolved to meet the growing demands of various electronic devices. In this article, Carisinyal will explore the different USB standards, from the early generations to the latest versions currently in use.

1. USB 1.0 & 1.1

USB 1.0 was the first standard introduced in 1996. While it may seem outdated now, it laid the foundation for USB technology. The maximum speed of USB 1.0 was quite slow by today’s standards, reaching just 1.5 Mbps for Low Speed and 12 Mbps for High Speed.

The Low Speed version was typically used for input devices like mice and keyboards, while the High Speed version was suitable for devices requiring more complex data transfers, such as printers and scanners.

In 1998, USB 1.0 was updated to USB 1.1, which maintained the same speed but improved stability and compatibility. Both USB 1.0 and 1.1 supported Type-A and Type-B connectors and allowed cables up to 3 meters long for maximum transfer speeds.

2. USB 2.0

USB 2.0, introduced in 2000, was a significant leap forward, offering a maximum data transfer speed of 480 Mbps. This version brought broader compatibility, supporting a variety of connectors, including USB Type-A, USB Type-B, Micro USB, Mini USB, and USB Type-C. The maximum cable length also increased, extending to 5 meters.

Thanks to its wide compatibility and reliable performance, USB 2.0 became the go-to standard for many electronic devices over the years, until it was eventually replaced by newer USB standards offering faster speeds.

3. USB 3.0 and USB 3.1

Next up are USB 3.0 and USB 3.1, which come in several variants. The first, USB 3.0 SuperSpeed, offers a data transfer rate of 5 Gbps, which is equivalent to 625 MBps. This speed is also shared by USB 3.1 Gen 1.

In 2013, USB 3.1 was introduced, with the faster USB 3.1 Gen 2, also known as SuperSpeed+ (offering speeds up to 10 Gbps or 1,250 MBps). Other names for SuperSpeed+ include USB 3.1 Rev 2 and USB 3.1 Gen 2.

Both USB 3.0 and 3.1 standards support USB Type-A, USB Type-B, Micro USB, and USB Type-C connectors. The maximum cable length for both SuperSpeed and SuperSpeed+ is 3 meters.

To differentiate USB 3.0 and above from earlier versions like USB 2.0, manufacturers often color-code the ports. Initially, blue was the standard, but now colors like red and orange are also used.

4. USB 3.2

In 2017, USB 3.2 Gen 2x2 was introduced, often referred to simply as USB 3.2 or SuperSpeed 20Gbps. As the name suggests, this version supports data transfer speeds of up to 20 Gbps, or 2.5 GBps.

Theoretically, USB 3.2 is compatible with USB Type-A, USB Type-B, Micro USB, and USB Type-C connectors. However, the maximum speed of 20 Gbps is only achievable when using the USB Type-C connector. This is because other connectors operate in a single-lane mode, limiting their maximum speed to just 10 Gbps.

5. USB4

USB4 was introduced in 2019, and its official name is simply "USB4", no spaces. This version is available in several variants: USB4 Gen 2x2, which supports speeds up to 20 Gbps, and USB4 Gen 3x2, which reaches speeds up to 40 Gbps.

USB4 Gen 2x2 can support a single 4K monitor and deliver 7.5 watts of power. On the other hand, USB4 Gen 3x2 supports dual 4K monitors, provides 100 watts of Power Delivery, and can offer up to 240 watts when using the USB Power Delivery 3.1 protocol.

USB4 is also compatible with Thunderbolt 3 and 4 and supports devices using older USB standards like USB 3.2 and USB 2.0.

One notable aspect of USB4 is that it exclusively uses USB Type-C connectors. This makes sense, as other connector types can no longer handle the high-speed data transfers that USB4 demands.

6. USB4 2.0

In 2022, USB4 received an update and was rebranded as USB4 2.0 or USB4 Gen 4x2. This update effectively doubles the data transfer speed, allowing USB4 2.0 to reach up to 80 Gbps.

Additionally, USB4 2.0 offers an asymmetric configuration, which allows transfer speeds of up to 120 Gbps in one direction (for example, to a monitor) while maintaining 40 Gbps in the opposite direction.

In September 2023, Intel released Thunderbolt 5, based on USB4 2.0. Thunderbolt 5 supports speeds of up to 80 Gbps, twice the speed of the previous version. It also supports DisplayPort 2.1, allowing you to connect two 8K monitors at a 60 Hz refresh rate simultaneously.

That concludes the overview of the various USB standards, from their inception to the present day. Looking ahead, it’s likely that new USB versions will emerge, potentially featuring designs and capabilities different from what we have now.