Some computer programs require a COM port (also called a serial port) to communicate with a Bluetooth enabled device. For example:
A program that synchronizes contacts with a mobile phone
A program that extracts Global Positioning System (GPS) coordinates from a GPS receiver
When you use the Add Bluetooth Device Wizard to add a Bluetooth enabled device to your computer, you create an incoming COM port, which permits your device to connect to a program on your computer, and an outgoing COM port, which permits a program on your computer to connect to your device.
Usually, you only need to use one of these COM ports.
To decide which COM port to use, you can
check the information that came with the program or your Bluetooth enabled device, or go to the manufacturer’s website.
If you're still not sure which COM port to use, try each COM port, one at a time, and use the one that successfully allows the program and your device to communicate.