This handy cable allows you to connect your CG-818 mobile base to your computer. You can then run software on your PC to analyze your energy use, upload data to the web and much more. One end of the cable has an 8 pin modular jack which connects to the data port on the meter. The other end has a USB plug which connects to the PC's USB port. The cable contains a USB to serial converter, so the meter appears as a COM port on the PC.