This depends on the GPS receiver used. Some GPS devices, use USB, some Bluetooth and other are using a serial connection.
To connect Bluetooth device, you need a Bluetooth dongle connected to your PC in order to read data from the device. From your Bluetooth manager software, connect to the GPS, and use the COMxx number assigned to read the data into Hydromagic.
To connect to an USB device, just install the drivers supplied by the manufacturer and plug in the GPS device. You can have a look at the ports section of your computers device manager to see which COMxx port has been assigned.
When using a serial GPS device, just connect this to your serial port and use this COMxx port in the software. If no serial plug is attached to your GPS's datacable, connect the common to the RS232 plug at pin 5, the data at pin 2 ( When using a 9 pin serial connector ).
