What is USB ?

USB (Universal Serial Bus) is a connectivity standard that provides specifications for

• Communication/data transfer protocol to be used (Asynchronous Serial Transmission)
• wires in a USB cable (2 for data, 1 for power, 1 for earthing)
• and the interface (connector) to be used (USB Type A/ USB Type B/ USB Type C etc).

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USB Versions, Release Dates and Max Data Transfer speed

Version	Data Rate	Release Date
USB 1.0	12 Megabits/sec	1996
USB 1.1	12 Megabits/sec	1998
USB 2.0	480 Megabits/sec	2001
USB 3.0	5 Gigabits/sec	2011
USB 3.1	10 Gigabits/sec	2014
USB 3.2	20 Gigabits/sec	2017
USB 4.0	40 Gigabits/sec	2019

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Connector Shapes

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Connector Images used in the article have been taken from Wikipedia