A printer cable connects a computer and a printer, with the most common type today being the USB A-to-B cable, which supports fast data transfer up to 480 Mbps. These cables are also available in USB 3.0 versions for even higher speeds and feature a flat, rectangular USB-A connector for the computer and a more square USB-B connector for the printer. Older, now-obsolete types include serial and parallel cables, which are difficult to find on modern computers and may require adapters to function.