I’ve written an article about DSC (Digital Selective Calling) which should appear in the January issue of 48° North, our local sailing magazine.

Mainly, I wanted to reiterate the Coast Guard’s advice that we register for a MMSI number, install the radio correctly, connect a GPS, and enter the MMSI number into our radios.

One of my secondary points in the article was that the vast majority of us don’t make any non-emergency use of the DSC communication infrastructure. My initial assumption had been that if more of us knew about these features, more of us would use them.

I no longer believe this. DSC appears to suffer from some significant user interface shortcomings that dissuade boaters from using it, and when you do use it, it doesn’t really do everything you might expect.

Recently, I had an opportunity to test some of the non-emergency DSC features with the help of a fellow C-Brat. We tested hailing a specific boat, hailing a Group MMSI, and sending a position request to a specific boat.

It all works, don’t get me wrong. But it’s a big hassle! Not "impossible", just awkward, and a little frustrating. There’s always plenty to do aboard a boat, and fiddling with a less-than-intuitive user interface, with bad ergonomics to boot, just doesn’t rate very high on most folks’ "to do" lists.

THAT’S why nobody uses the other DSC features, in my opinion.

Here’s what I’m talking about: On smaller VHF radios, there is no keypad, so entering each digit of a nine-digit MMSI number is accomplished with a knob or a pair of up/down keys. This isn’t difficult, but it isn’t especially pleasant. The display is small, and if the boat’s moving, those tiny numbers are sort of jittering around while you try to keep an eye out for traffic and logs, AND read the number off the handwritten note or email you printed out at home.

This one tiny obstacle, all by itself, is virtually guaranteed to prevent 90% of potential users from ever bothering with it. Sometimes I think manufacturers forget that most of their customers don’t really love the technology for its own sake; they love tools that make it easier to accomplish something.

But bear with me a moment. So once you’ve got your target vessel’s MMSI entered, the system doesn’t always do what you might expect, and sometimes you’re left wondering if you made a mistake. The feedback can feel somewhat incomplete. Did it work? Did I do it right? Should I try again? I’m not really sure.

Or here’s another example: Some systems don’t do what you might expect with other vessels’ position data. I’ve got a Raymarine C-80 connected with NMEA cable to my Ray-54 DSC VHF radio. The chartplotter forwards my position info to the radio, and the radio sends…what?…back to the chartplotter.

I’m not sure it sends anything. In fact, in an earlier post about NMEA Multiplexer workarounds, I believed that the VHF radio was a "listen-only" NMEA device, receiving GPS position info without sending anything back over NMEA.

But when I sent a DSC "position request" call to my friend, I got the position info back from his DSC radio, and it appeared on the radio’s display. Without even thinking about it, I did something that felt completely natural and intuitive: I looked at the chartplotter to see where he was.

Oh wait…the chartplotter doesn’t KNOW where he is, if my understanding is correct, because the radio doesn’t send anything out over NMEA.

So hold on. I’ve got an AIS-ready chartplotter and it won’t display the positions received from my DSC radio? What if somebody sent a DSC distress message? Am I really expected to transcribe the lat/long by hand over to my chartplotter?

No, that cannot be right. I must have misunderstood. The radio must be both a talker and a listener on the NMEA network. Maybe I’ve just got some configuration setting wrong, and that’s why the target wasn’t displayed on my chartplotter. This seems so obvious that now I’m not at all sure what the reality is.

If any readers know something more about DSC radio integration with chartplotters, particularly on Raymarine C- and E-series equipment, please let me know. Obviously, I’m feeling a little bit confused!

Anyway, the point is that DSC appears to be a powerful technology with a lot of potential, but it doesn’t seem like it’s really being explored thoroughly. I’m definitely not out on the bleeding edge of marine electronics the way Ben Ellison of Panbo is, so maybe I’m just unaware of the various cool recreational and commercial DSC spin-off applications that, it seems to me, ought to be inevitable. Can anybody help fill me in? Please?