USB pinout diagram @ pinouts Pinout of USB and layout of 4 pin USB A or USB B plug connector and 4 pin USB A / USB B / mini-USB jack connectorUSB (Universal Serial Bus) designed to connect peripherals such as mice, keyboards, scanners, digital cameras, printers, hard disks, and networking components to PC. USB Connector Pinouts - HobbyTronics USB Connector Pinouts. USB is a serial bus. It uses 4 shielded wires: two for power (+5v & GND) and two for differential data signals (labelled as D+ and D- in pinout). In a USB data cable Data+ and Data- signals are transmitted on a twisted pair with no termination needed.