USB connectors – and, by extension, USB ports – can be found in two different styles: type “A” (for hosts and USB hubs) and type “B” (for peripheral devices). In addition, USB plugs come in three different size ranges: standard, mini and mini.Here is a general breakdown of how connector styles vary by size class, and the applications each connector is used for:
Standard USB: The standard is the size of the original USB connector, which is also the largest string.The standard size "A" connector is A long and extremely narrow rectangular shape (approximately 4 mm x 12 mm), while the standard "B" connector is still rectangular, but has A shorter and wider ratio (approximately 7 mm x 8 mm, they are more square).Standard USB connectors are typically used with "standard" peripherals, such as printers, keyboards, computer mice, and scanners.
Mini USB: Mini USB connectors for small portable peripherals such as digital cameras, cell phones, Pdas, and MP3 players are designed to be more compact and space-efficient than standard USB connectors.Unlike standard A and B connectors, mini A and B have very similar shapes;However, they can be distinguished by the top half of their vertical sides: mini A's side is straight, but mini B's side is round.
Micro USB: In January 2007, the USB-IF approved the most space-conscious connector size to date: Micro USB. Micro USB connectors are approximately 50-60% smaller than mini connectors, and replace Mini USB in many new PDA's and Smartphones.