QRA JO01OX, WAB TM23, Fists #16909 GQRP #15161 DMR-ID 2342670

NMEA data is basically simple ASCII strings that represent some form of data. They are easily readable and typically look like:


They are transmitted using the electrical RS-422 standard and this project is designed to convert the data flow from the RS-422 standard to something that can easily be plugged into a USB port on a typical PC. At one end we have an optical isolation circuit and at the other we have an Arduino Pro Micro. When plugged into a PC USB socket the Arduino Pro Mico will appear as a standard COM port.

This can easily be built on Veroboard and the whole device assembled as:

The Arduino is programmed via the USB connection and when connected to a 4800 baud NMEA data feed the data gets sent out of the USB at 9600 baud.

For further information about the software please contact me via the Contact page.


  1. Typical optical isolation circuit.