Another weekend, another learning experience. "The plan" is to interface the Garmin chart plotter with the Standard Horizon DSC VHF so that when the DSC button is pushed we will be transmitting our position. Part of the plan was also to interface the chart plotter with the auto pilot. Having messed with 12 volt accessories on cars and boats for longer than I care to think about these days, I assumed that this would be a pretty straight forward project. Identify wires, make connections, hit the battery switch and away we go....... Not so much. I looked at the wiring diagrams for both pieces and find them less than helpful. I believe they assume that I am a technician or have more experience than I do.

Conditions were less than ideal with a rain/wind storm going on. It was like being inside a snare drum, the rain was being driven by the wind and was actually coming through the teeth of the zipper on the shrink wrap access door. Anyhow, there are 4 very small NMEA wires on the Garmin, two in and two output. There are also 4 very small wires on the VHF, two in and two output. Initially I assumed the Garmin outputs would go to the VHF inputs but now I'm not sure what goes where. The VHF speaks in terms of + and - side inputs, the chart plotter only speaks of two outputs, no polarity given. Is it a straight output to input or is their a handshake involved in the data exchange of the NMEA protocol where we need to have two inputs and two outputs? There is no SeaTalk bus on the boat, I was going to make the connections directly between the components.