USB pinout diagram @ pinouts Mini-USB pinout and Micro-USB pinout are slightly different: standard USB uses 4 pins while Mini-USB and Micro-USB uses 5 pins in connector. The additional pin is used as an attached device presence indicator. USB pinout signals. USB is a serial bus. USB pinout, wiring and how it works! - Electroschematics USB is the short form of Universal Serial Bus, a standard port that helps to connect computer peripherals like scanner, printer, digital camera, flash drive and more to the Computer. The USB standard supports the data transfer at the rate of 12 Mbps.