Four PC share one Serial device including printer & barcode reader, or one PC connects to four serial devices. This video switch has built-in 5-Pin DIN connector with Keyboard Reset for sharing devices like AT Keyboard or MIDI but usage is optional. It has gold-plated contacts with metal case, fully-wired for maximum application compatibility, heavy duty sealed rotary switch to prevent dust and moisture, and 1 Year Warranty. (Connectors: 5 Din5 Female/5 DB9 Female)