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What is the Difference between USB Type A and USB Type B Plug/Connector?

Hardware: Serial>>RS-232

In the Catalog for USB-232/485 Series Interfaces, it says that the 1-port interface has a USB Type A plug whereas the 2- and 4-port interfaces have a USB Type B connector. What is the difference? Do I need any additional hardware to connect either one to my computer?

The USB connector on your PC is a type A connector. It is recognized by its rectangular shape. Devices that use type A connectors tend to be smaller devices such as your computer mouse or PDA connector. You can plug these directly into a computer with a type A male to type A male USB connector. 

However, many larger USB peripherals, such as printers and scanners, require a USB Type B connector and hence require a type B plug. The type B connector has a square shape and is normally used in larger instrument control. In order to connect a USB type B peripheral to your computer, you will need to purchase a USB type A to B Cable. This cable is quite common and can be purchased at any electronics store. 

In the following image, the type A connector is on the left and the type B connector is shown on the right. For more information, see the Related links for Section 2 of the Developer Zone Tutorial: Six Things You Need to Know about USB Control.

USB type A and type B

Related Links:
Developer Zone Tutorial: The Future for New Bus Technologies in Instrument Control and Connectivity
Developer Zone Tutorial: Six Things You Need to Know about USB Control
External Link: Universal Serial Bus -


Report Date: 10/07/2003
Last Updated: 01/14/2014
Document ID: 326BPC5L

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