Dwight Watt - Newspaper Article #358 11/16/2016

Question: Why are some USB outlets blue?


The blue plugs and outlets are USB 3 plugs and outlets. Most USB devices for a number of years were USB 2. USB 3 runs much faster than 2 and is used on newer devices.

USB uses the rectangle plugs that many of our devices use. There is a standard size of the plug and then there are micro and mini USB plugs. The standard size is used most often where we connect in to our computers. The plug on the end that plugs to the devices is usually a mini or micro plug. USB devices include disk drives, thumb drives, cameras, phones, keyboards, mice and lots of other devices. It was named universal serial bus and has become a universal type interface like it was named.

The USB 2 and USB 3 plugs are the same size and shape and both will work interchangeably.

USB 2 works at 480 megabits per second and was half duplex which meant communication only occurred one way at a time but could go both ways like a CB radio or ham radio. USB 3 works at 5 gigabits per second which is 10 times faster than USB 2 and also is full duplex meaning communication can occur both ways at the same time like a phone which also increases speed.

To distinguish the plugs apart, the standard was adopted that USB 3 would have blue outlets and USB 2 would continue black. If you have a USB 3 device, you want to plug it in the blue port on your PC so the data transfers the fastest. However, the USB 3 ports are backward compatible with USB 2 so you can plug USB 2 devices in them but they will only operate at 2 speed. Likewise, you can plug USB 3 devices in a USB 2 port and they will work just at USB 2 speeds. Most computers the last few years have included USB 2 and 3 ports on them.

Thanks Rickey for the question