What are USB connectors?
Universal Serial Bus (USB) was developed in the 1990s in an effort to simplify the connections between computers and peripheral devices. It has become widely popular due to its compatibility with many platforms and operating systems, its low cost of implementation, and its ease of use. Most computers that are built today come with several USB ports, and USB is the interface of choice for most home and office peripherals including printers, cameras, modems, and portable storage devices.
Found on host controllers in computers and hubs, the A-style connector is a flat, rectangular interface. This interface holds the connection in place by friction which makes it very easy for users to connect and disconnect. Instead of round pins, the connector uses flat contacts which can withstand continuous attachment and removal very well. The A-socket connector provides a “downstream” connection that is intended for use solely on host controllers and hubs. It was not intended for use as an “upstream” connector on a peripheral device. This is critical because a host controller or hub is designed to provide 5V DC power on one of the USB pins. Though not that common, A-A cables are used to connect USB devices with an A-style Female port to a PC or another USB device, and for data transfer between two computer systems. Note: Typically an A-A cable is not intended to connect two computers together or to connect a USB hub between two computers. Doing so may cause irreparable damage to your computers and may even present a fire hazard. Check with the manufacturer before using an A-A cable for data transfer.