The Raymarine core packs with built in rate gyros output the heading at 10 / sec via the NMEA output(s). The SeaTalk data is still 1 / sec. Our Raymarine plotter/radar only gets 1 / sec via SeaTalk until I hook up the NMEA, then it is 10. The Raymarine plotter sees the NMEA input at 10 / sec and it gets priority.