IS WACKY WIRING FATAL?
Q: I recently went behind my nav station to hook up my old chartplotter to my 4-year-old GPS and discovered that the GPS data leads were taped together with several of the bare wire ends touching each other! Is my connection cooked?
Tom Redler, Marina Del Rey, CA
GORDON WEST REPLIES
Most equipment with the NMEA 0183 “talker and listener” 4,800 Baud data lines is protected by an isolation circuit within the equipment, protecting against accidental shorts or wrong hooks-ups. So I’d say proceed with a trial hookup and study both equipment hookup diagrams so the GPS talker line (usually the white and brown wires) goes to the chartplotter listener line (usually the yellow and green wires) with the shield grounded only at the GPS talker.
The National Marine Electronics Association (nmea.org) has technician training programs for these kinds of equipment tie-ins, so if it doesn’t work find an NMEA dealer near you and ask for a certified marine electronics technician to come aboard with their handheld data line test gear to get you going with that new plotter!
But again, try it yourself first and wait for about a minute to see if the chartplotter recognizes the GPS input data connection on its own.
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