Plug & Pray
Part 2: Finally, one technician suggested a solution: Make my own cable.
By Richard Thiel — June 2005
All I had left to do was connect the chartplotter to the VHF. A few minutes of scanning the manuals and I understood that all I needed to do was simply plug in one end of a cable to the chartplotter port marked “NMEA output” and the other end of the cable to the VHF port marked “GPS.” And that’s when my troubles began.
The first thing I did was look in the boxes the new units had arrived in for a cable that would make the connection. Nothing. Okay, I figured I probably had to go to an electronics store and buy one, sort of like the cables you buy at stereo stores to connect your CD player to your tuner. I called a few shops, but no one had any idea what I was talking about. Obviously I was going to have to order a cable from one of my units’ manufacturers. I called both and got the same answer—basically, “Huh?” In both cases, the technician on the help line was unaware of any such cable and suggested I contact the other manufacturer to find it.
Finally, one technician suggested a solution: Make my own cable. He insisted that this would be an easy task. Simply get the appropriate plug for each unit from its manufacturer and connect them via a piece of multistrand cable that I could get at my local Radio Shack. That seemed doable, so I called the manufacturers, and each shipped me the plug for its unit. Now all I needed was the multistrand cable. But how many strands?
When I looked at the two plugs I noticed three basic problems. First, one plug had six pins and the other had five. Second, I had no idea which pin should be connected to which other pin. Third, the plugs had these funny tubular receivers into which the bare wires were supposedly inserted. But how to secure them? Crimp? Solder? Back to the consumer help lines.
Incredibly, neither rep had any idea of how to connect the wires to the plugs but they could tell me how to match pin to pin—sort of. I had to pull out the wiring diagrams for each unit—thankfully they were included in the owner’s manual—and note what each pin was for. This proved to be a bit more of a job than it sounded at first, because there was no common color-coding. Fortunately, there was common terminology. All I had to do was match four common leads: NMEA OUT (+), NMEAOUT (-), NMEAIN (+), and NMEA IN (-). This turned out to be pretty easy. I just purchased some five-strand cable (I couldn’t find four-strand) and made up my own color-coding. I then found a technician who explained how to secure the wires to the plugs (solder), and after some time (soldering small stuff is hard!), I had my cable.
I plugged it in, powered up the two units, and said a little prayer. There on the VHF display were my GPS coordinates! I have to tell you, I was pretty darn proud. The whole job had taken me four weeks—not exactly plug and play, but a whole lot better than an indecipherable error code and a toll-free number.
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This article originally appeared in the August 2005 issue of Power & Motoryacht magazine.