USB Standards

USB 1.0, USB 2.0, USB 3.0. What does it all mean?

USB 1.0 – Where it all started

USB standards (starting with USB 1.0) were first released in 1996 but not much was done using USB until USB 1.1 came along a couple of years later. Maximum data transfer speed of these standards was 1.5Mbps (Megabits per second). Keep that number in mind as you work your way down the page. USB offers outstanding capability, allowing multiple peripheral devices to be connected at once. As the standards improved over time, backward compatibility was built in so you could always use older cables and devices with newer cables and devices, but they would be limited by the maximum data transfer speed of the oldest standard device/cable in the chain.

USB 2.0

USB 2.0 came along in 2000 and took the maximum data transfer rate up to 480MBps. This is when the use of USB really started to take off with a quantum leap in speed. Type A USB connectors that are black are USB 2.0.

USB 3.0

in 2008 another huge leap came along, with maximum data transfer speeds of 5.0Gbps – or ten times faster than the USB 2.0 standard. Again, backward compatibility meant that all of your existing cables and devices could still be used and then upgraded as needed. For reference, a standard definition movie would take over 2 hours to download using USB 1.0, or about as much time as it would take to watch it. Ahhh… the good old days. USB 2.0 cut that down to a few minutes. But USB 3.0 reduced your wait time to under 30 seconds! That’s not even enough time to make the popcorn. USB Type A connectors that are blue are USB 3.0 or later. This was the first standard that was labeled SuperSpeed, and sometimes has the SS logo on the connector.

USB 3.1 and USB 3.2

When USB 3.1 came along the transfer rate was increased to 10Gbps. USB 3.2 took that up to 20Gbps. Some, but not all, connectors will have SS10 or SS20 printed on the connector.


You likely didn’t notice, but there is no space between USB and the number 4. This re-branding is intentional. USB4 is currently undergoing review (early 2020) and will offer data transfer speeds of up to 40Gbps. USB4 uses the USB C connector exclusively as the electronics world transitions to USB C. Perhaps the single biggest advantage of USB4 is the ability to have a USB C connector at each end of the cable. One cable to rule them all! Another standard that uses the USB C connector is Thunderbolt 3, which was developed by Intel. I’ll talk about Thunderbolt 3 in a moment. USB4 will offer much of the capability of Thunberbolt 3 and should be compatible with almost all Thunderbolt 3 use cases.

Thunderbolt 3

Intel developed the Thunderbolt 3 standard independently of the USB Implementer’s Forum (USB-IF). The great strength of Thunderbolt 3 (and ultimately USB4) is the ability to transfer data, and power through one cable. Plug your Thunderbolt 3 laptop into a dock with your USB C cable and you’re good to go. Remember, it can handle up to 100 watts of power, so you can charge your laptop quickly and easily while getting work (or play) done. Look for the Thunderbolt logo on the connector, typically with the number 3.