The HR12 is a thumb-sized adapter that is USB powered and that complies with NMEA 0183. The HR12 is also compatible with RS-422 and RS-232 systems. The serial input is opto-isolated and the differential output will drive either single-ended (RS-232) or differential (RS-422) interfaces. Data rates up to 38.4 Kbaud are supported. A flashing LED indicates data activity. It works with MS Windows, MAC, and Linux hosts