Many color instruments and spectrophotometers in use today come with a serial cable to connect and communicate with a computer. However, serial ports are a thing of the past and very few PC's come with a serial port as standard configuration these days. While you can always install a serial port, an easier way to connect to the PC is to use a Serial to USB adapter. This is a special cable that plugs into the serial port output of your spectrophotometer on one end and plugs into a USB port on the computer on the other. This circumvents the need for a serial port on the PC.