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USB 3.0 has arrived, what is the difference between USB 1.1, 2.0 and 3.0?

USB standards, devices, connectors and information


USB (Universal Serial Bus) ports have been a common port on PC's for a number of years. It is now the main way of connecting devices to a PC.

The introduction of USB allowed devices to be installed more quicker and easier than before. PCs no longer needed to be shutdown first, before adding a device to your Computer otherwise it would crash and BSOD. With USB the device could be connected and the system would then detect and install the device, or prompt for a driver to be installed. This is also known as hot-plugging or hot-pluggable, or more common plug and play.

Once a peripheral as been installed you can plug the device in and remove at any time, this can be particularly helpful if you need to print or scan or connect a backup device to the system with out having to shutdown and reboot.

Before USB connection methods were limited to either Serial or Parallel these were far slower in comparison and led to the com ports being phased out as they are seldom used. Primarily functions were for Modem, Printer and Mouse connections.

The first USB standard was USB 1.1 and can be found in systems prior 2001 after this USB 2.0 was introduced and has been the default standard since. The transfer rate of USB 1.1 was limited to a maximum of 12Mbp/s which at the time was still relatively quick.

USB 2.0 has a higher maximum rate of 480Mbps, which is 40 times faster than USB 1.1.

To allow you to use any version you will need compatible ports on your PC and use a compatible cable or hub.

USB Connectors

USB Connectors A and BUSB Connectors A and Mini-B

A and B connectors are the most common, although Mini-B connectors are common on Digital Cameras and hubs along with other products.

USB 3.0 Motherboards and devices started to appear in 2010 with USB 3.0, this builds on the USB 2.0 standard by allowing faster speeds of transfer over 2.0 (x10).

Your Computer can use 3.0 devices through a USB 2.0 port, obviously at the lower speed. Or with 3.0 hardware on a seperate card and leads you can retro fit and add new ports to devices.


USB connectors can be found on just about every device from keyboards and printers to watches with flash memory built-in.

USB HubUSB Biometirc Reader
USB Flash DriveUSB Flash Reader


How to tell if your system is USB 3.0 ready?

The easiest way is to look at the connectors they will look slightly different to USB 2.0 and are also Blue in colour over the traditional white USB 1/2 connector. Or check your Device Manager for enabled hardware.

USB 3.0 Ready Computer Image - Hardware in device manager

How to tell if your system is USB 2.0 ready?

You can tell if your system can use USB 2.0 my opening device manager and looking for the Universal Serial Bus (USB) section often at the bottom of the list. By expanding these options you will see either Standard Host Controller or Enhanced Host Controller. Standard means that your system uses USB 1.1, and Enhanced means you can use USB 2.0 and USB 1.1 as you can still use USB 1.1 devices but obviously at the reduced rate.

Example of a system with a standard host set-up

Standard USB Host View

Example of a system with a enhanced host set-up

Enhanced USB Host View

What happens if a USB 2.0 device is connected to a USB 1.1 system?

The whole USB system is reduced to the USB 1.1 standard of 12Mb/s. Some operating systems including Windows 2000 and XP did notify the user of this change and any available options.

How many USB devices can I connect to a PC?

USB allows you to connect a maximum of 127 devices at a time, of course this is via serveral hubs and interlinked connections. Most PCs have four-six as standard.