Output from NMEA 0183 to SeaTalkng convertor

[Chuck - Raymarine - Moderator]

Welcome to the Raymarine Forum Lew,

Q1. I am using two NMEA 0183 to SeaTalkng convertors in my system. The units are fed by a GPS via the SeaTalkng backbone and powered by 13.65 volts. In an open circuit condition and the plus output is a steady 13.65 volts and the negative output toggles from 0.64 volts to 12.1 volts. This doesn't seem right as the plus output is always above the negative. My two Icom receivers accept the data properly but a third unit (stabilizer) does not. Shouldn't the plus output be more like 6 volts or so?
A2. Please click here to view a FAQ addressing this subject. When operating in NMEA 0183 mode within a SeaTalkng/NMEA 2000 backbone in which GPS data is present, an analog meter's needle should bounce between approximately +0.3VDC and +5VDC. Raymarine product's can support up to three NMEA 0183 listeners. However, it is sometimes necessary to install a NMEA 0183 expander when interfacing more than two NMEA 0183 listeners to the Raymarine device. Should an analog meter connected between NMEA 0183 OUT+ and NMEA 0183- leads from the SeaTalk to SeaTalkng Converter not behave as stated here, then it is recommended that SeaTalk to SeaTalkng Converter be tested by Raymarine’s Product Repair Center.

Q2. Is an equivalent circuit schematic for the convertor output available?
A2. Unfortunately, schematics are not available for currently manufactured Raymarine products.