USB connector types

What is a USB connector?
Universal Serial Bus (USB) is a connector created to simplify connections between computers and peripheral devices. It was developed in the 1990s, and has become very popular due to its compatibility with many platforms and operating systems, its low implementation cost and its ease of use. Most of the computers that are built today come with several USB ports and this connector is the interface of choice for most home and office peripherals such as printers, cameras, modems and portable storage devices.
Type A USB connector
A type A connector is a flat, rectangular interface that holds the connection in place friction, which makes it very easy for users to connect and disconnect. Instead of round bars, the connector uses flat contacts that can withstand continuous connections and disconnections very well. The Type A connector provides a downstream connection that is designed to be used only on the host controllers and hubs.
Type B USB connector
The USB Type B connector is designed for use with USB peripheral devices. The type B interface is square in shape, slightly bevelled at the corners at the top ends of the connector. Type B connector is an upstream connector that is only used in peripheral devices. For this reason, most USB applications require an A-B cable.
Type C USB connector
The Type C USB connector is the newest USB connector on the market, has a reversible symmetrical design and can be plugged into any USB-C device using either end. A USB-C cable is capable of carrying signals USB 3.1, USB 3.0, USB 2.0, and 1.1
When connecting two USB 3.1 devices, the USB-C cable will support data transfer speeds twice as high as the existing USB speed (up to 10Gb / s).
Micro USB connector A
Recognized as USB-IF, this connector can be found on the latest mobile devices such as mobile phones, GPS units, PDAs and digital cameras. A micro-USB-A offers a physically smaller connection in size to a USB mini-B, while still supporting the high transfer rate of 480 Mbps. It is identified by its white receptacle and a compact 5-pin design.
Micro USB connector B
Recognized as USB-IF, this connector is found on the latest mobile devices such as mobile phones, GPS units, PDAs and digital cameras. A micro-USB-B offers a physically smaller connection in size to a USB mini-B, while still supporting the high transfer rate of 480 Mbps. It is identified by its white receptacle and a compact 5-pin design.
Micro USB Connector A-B
Designed exclusively for mobile USB devices, this connector can accept a micro-USB A or Micro-USB B cable connection. This interface can be easily identified by its gray receptacle and a compact 5-pin design. This type of connector only exists as a receptacle on mobile devices and will not exist on a cable.
Mini-B (5-pin) USB connector
One drawback of the B-style connector is its size, measuring about half an inch on each side. This made it unsuitable for many compact personal electronic devices such as PDAs, digital cameras, and cell phones. As a result, many device manufacturers began miniaturizing the USB connectors with this Mini-b. The Mini-b 5-pin is the most popular style of mini-B connector, and the only one recognized by the USB-IF. By default, a mini-B cable has 5 pins.
Mini-B USB connector (4-pin)
It is a connector used in digital cameras.