Female USB connectors allow the male part of a USB cable or plug to be inserted into any compatible device. Once coupled in this way, the two devices can share both power and data over their common USB connection.

USB stands for Universal Serial Bus, a common standard launched in 1996. Before this, there was a much wider variety of different connectors commonly used for linking PCs and compatible hardware. Examples you might be familiar with include multiple versions of serial ports, D-Sub, and parallel ports.

The body responsible for developing, maintaining, and updating the USB standard is called the USB Implementers Forum, or USB-IF. To date, there have been four main generations of USB released: USB 1.x (which had various subcategories), USB 2.0, USB 3.x (again, with subcategories), and USB 4. You will often see these referred to as USB gen 1, USB gen 3, and so on.

Between these four generations and the various shapes and types of USB connector available, we now have quite a wide range of USB port and socket standards available to choose from. The main difference between older and newer USB generations is the speed at which they can transfer data between one device and another. This is shown in the chart below: