Tech Tip: Breaking Down USB

In this month's tech tip, Sam breaks down the different types of USB.

USB 3 Offers SuperSpeed
USB 3 is an awesome technology offering us over 10x the Data Rates of USB 2 as well as introducing the omnidirectional Type C connector. But that does not mean that USB 2 has met the end of its usefulness; in fact, USB 2 lives on as parallel to USB 3 in the USB 3 and Future USB 4 specifications. 

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USB 3.2 Dual Bus System Architecture

USB 3.2 Dual Bus System Architecture ©2017 USB 3.0 Promoter Group

In USB 3, two separate bridges can be used between USB Devices, Hubs, and Hosts. 

The SuperSpeed Bridge (USB 3)

• Designed for High Bandwidth Signals such as 4k MJPEG Video or SSD read/writing for gaming.

The Hi-Speed Bridge (USB 2)

• Designed for legacy USB functions such as Mouse/Keyboard, UVC Cameras, and UAC Audio.

There are two important factors to remember when using USB nowadays:

• Some cables/ports may have some functions. Whether it be USB 2 or 3 functionality only, all the way down to the cable being power only.
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• The two USB bridges are separately clocked even for isochronous (occurring at the same time) USB events; meaning that a device that captures both 4K Video and Audio can suffer severe video delay because of the High Bandwidth video signal. This causes major issues in soft codec conferencing as audio is arriving before a presenter’s lips move.
  

​Ultimately, these factors can cause less problems by understanding the symbols provided by USB, which help you to discern the capabilities of a port.