Do USB Generations Matter?
Posted on July 5, 2021
Like every other technological standard, the Universal Serial Bus (USB) has evolved over the years. From standard USB to USB 2.0, and now USB 3.0, it has been upgraded twice.
But do these USB generations even matter? What exactly is improved in every version? Let’s find out.
Transfer Speed: The Key Metric
The capacity of a USB drive has little to do with the type of connection in play. That depends entirely on the capabilities of the device in question. What the USB generation does decide is the quality of the connection. The most obvious effect of which is on the rate of data transfer.
The transfer speed of a USB port has steadily increased since its launch in 1996. The original USB 1.0 could only manage speeds of up to 12 Mbit/s in its ‘Full Speed’ mode (and just 1.5 Mbit/s in its ‘Low Speed’ mode). This was boosted to 480 Mbit/s in the USB 2.0 standard, making USB storage devices like pen drives practical.
But the biggest change came with USB 3.0. With the new SuperSpeed transfer mode, this standard offers a data transfer rate of a whopping 5 Gbit/s. That is further boosted in the sub-generations of USB 3.0, to 10 Gbit/s or even 20 Gbit/s.
This increased rate of transfer also carries over to the electric flow. Charging systems using the new SuperSpeed channels can draw extra currents ranging from 150 mA to 900 mA.
The ABC of Connectors
USB-A, USB-B, and now, USB-C. Along with the USB generations, the type of connectors used with this interface has also changed. USB-A was the original and still the most ubiquitous type of connector. Most of the USB ports you find on a computer tend to use the type A connector.
Both USB 2.0 and 3.0 connections are supported through a type A connector, with only the host port being different. The type C connectors are only used by the newer 3.1 and 3.2 versions to implement the new SuperSpeed mode that makes a higher transfer rate possible.
The USB-C connector has another advantage. It enables full-duplex connections, instead of the half-duplex possible before. What this means is that the connector allows two-way connections, with data being transferred in both directions at once.
The Sub-Generations of USB 3.0
Until USB 2.0, things were relatively simple. There were no further releases with incremental changes. But with USB 3.0, this changed.
Sub-generations were introduced, improving upon existing features and offering newer functionalities not present in the original standard. Making things even more complicated are the variants of these sub-generations.
Here is a look at all the versions of USB 3.0 available today.
The 3.1 version primarily improves upon the SuperSpeed mode, doubling the transfer rate. Of course, not all connectors can support his transfer mode. Only USB-C connectors have the additional data lanes capable of this enhancement.
This has led to the splitting of the standard into two versions: USB 3.1 Gen 1, which uses the legacy type A connectors to offer a transfer rate of 5 Gbit/s, and the USB 3.1 Gen 2 that relies on type C connectors to give speeds of 10 Gbit/s under SuperSpeed+.
The USB 3.2 generation doesn’t really add a new data lane or technology – it just repurposes existing features of the USB-C connectors to give even faster transfer speeds.
The principle is simple: type C connectors come with two data lanes to allow for full-duplex connections. When this capability is not needed, data can be sent over both lanes simultaneously to achieve twice the speed.
So this divides the transfer modes into four versions. USB 3.2 Gen 1 and USB 3.2 Gen 2 are identical to their 3.1 counterparts, using type A and type C connectors respectively. The newer modes are labeled USB 3.2 Gen 1×2 and USB 3.2 Gen 2×2. As the names suggest, they use USB-C cables to transfer data through two channels at once. This achieves transfer rates of 10 Gbit/s and 20 Gbit/s respectively.
As we have seen, USB generations have a significant impact. The data transfer speed jumps by leaps and bounds between one generation to another.
For a normal user, this greater speed is just a convenience, but for industrial computers, it is nothing short of critical. Higher data transfer rates are essential in many applications that involve multiple USB connections.
Embedded systems can be expensive to upgrade. But if your systems are already in their EOL stage, moving to a newer USB generation is definitely worth it.