Universal Serial Bus (USB) is pretty much the standard interface for most computer devices nowadays. We use USB ports to connect printers, keyboards/mice, and smartphones, to name a few. But do you know how to tell the difference between a 1.x and 3.x port? Here's how to determine what kind of USB connection your computer or device has.

When it comes to USB ports, what defines the features are called specifications (1.1, 2.0, etc.). USB connectors, whether the receptacle on your computer or the plug on the end of a cable, are often colored-coded to tell what specification it is. The receptacle's color is not part of the actual USB specifications and may vary from vendor to vendor. The following is a list of USB specifications and the color usually associated with it.

USB specifications by color

White USB connector - USB 1.x



White Type A USB 1.x plug

This was the first specification for USB and was released in 1996. It had some issues with extension cables/hubs and wasn't widely adopted. It wasn't until version 1.1 in 1998 that it started to be used in manufacturing devices. Typically white connectors are USB 1.x, but quite a few are USB 2.x compatible. The transfer rate for USB 1.X was kind of slow at only 12 Mbps (megabit per second).

Black USB connector - USB 2.x



Black Type A USB 2.x plug

This is the second specification for USB and was released in 2000. It was labeled 'Hi-Speed' because it had a maximum transfer rate of 480 Mbps (megabit per second). It is entirely backward compatible with USB 1.x.

Blue USB connector - USB 3.x



Blue Type A USB 3.x plug

This is the third specification for USB and was released in 2008. It defines a new SuperSpeed mode, with transfer speeds up to 5 Gbps (gigabit per second). It is entirely backward compatible with USB 2.x.

Red or Yellow USB connector - Sleep and Charge



Red Type A USB Sleep and Charge plug

This is not a USB specification, but more of a feature. This color indicates that the connector does not power off during sleep or standby mode. On laptop or desktop computers, they are great for charging external devices like smartphones. Its specification can be any of the above, so check your computer or device documentation for the exact one.