The A-B box is an analog switch box used to connect multiple peripherals to one computer. The pictures are examples of the front and back of an A-B box. The back of the A-B box has an INPUT-OUTPUT port, and A and B ports to connect each of the devices. In our example, two parallel port printers connect to the box on the A and B ports and the computer connects to the INPUT-OUTPUT port. The computer user could then switch between the A and B printer on the same computer without having to disconnect and reconnect the printers to the computer.