DY NMEA 0183 to USB, looks handy

... written for Panbo by Ben Ellison and posted on Apr 26, 2010

That's Digital Yacht's just announced NMEA 0183 to USB adapter, all of it, and it's just $49.  Wire it to a multiplexer, AIS, or some other 0183 RX/TX port and any 0183 message will purportedly be seen by software running on the attached computer.  The adapter has LEDs that flicker for transmitted and received data, and it can be set to either 4,800 or 38,400 baud. The included software is said to work with PCs, Macs, and even Linux-based systems, and there's a bonus...

The bonus is DY's SmarterTrack Lite AIS viewing software (PC only, I think), which is a subset of the full charting SmarterTrack I first saw in Miami.  Since then I've spent a little time with the downloadable SmarterTrack demo, and was pleasantly surprised to find new software that seemed so quick and stable.  It's also loaded with AIS features, including transponder management.  At any rate, I can't find the adapter at www.DigitalYachtUSA.com yet, and that link still redirects to the DY mother ship in the U.K., but I'm told that they're ready to ship, and you might try emailing [email protected] (or calling 978-277-1234).  Cherry on top:  The press release, which you can find in this list, ends with "The company will also shortly be launching a version for use with NMEA 2000 based systems."



49 bucks for a piece of wire? Could someone make one by cutting off one end of any USB cable>

Posted by: Rick at April 26, 2010 4:51 PM | Reply

How is this different from the squillions of RS-232 to USB connectors that already exist (besides the bare wires instead of DB-9 connector)?

Posted by: Anonymous at April 26, 2010 7:10 PM | Reply

Click on the photo, Rick; you'll see there is a miniature circuit board built into the USB connector. As Anonymous notes, this is an RS-232 to USB serial adapter. I guess the connection can be done a little cheaper with an office style adapter, but you may need to wire a db-9 connector, you'll end up with a another lump or two in your system, and not all adapters work well with NMEA 0183 anyway. This design is very clean and purpose built.

Posted by: Ben at April 26, 2010 7:22 PM | Reply

This looks very similar to the TTL-232-R-5V (low power) cable I purchased for $20 from an electronics parts supplier. The cable I purchased is made by FTDI...
...who also make a RS232 level cable and versions which they do not have pictures for that have the bare wires of the above products.
FTDI makes these cables for resellers with their packaging specifications.
I use these adapters for my NMEA multiplexor and one to control my ICOM-M710.
Digital Yacht's $49 is not a bad price for a retail packaged version, but if you are in the marine electronics installation business you can do better by buying the FTDI adapter, and you can get bulk pricing.

Posted by: Evan at April 26, 2010 8:03 PM | Reply

One benefit I see with this cable/adapter is it will handle the differential signal that is true NMEA-0183 that most marine instruments use. While some "office" adapters can handle it, not always..


Posted by: GPSNavX at April 26, 2010 8:41 PM | Reply

FTDI shows up all over. When I plugged in an Actisense NDC-4 today (it comes with a USB connector), Windows asked if I wanted to install the FTDI drivers.

Posted by: Adam at April 26, 2010 9:40 PM | Reply

As NMEA is RS422(5volt differential async), why not simply use a USB to RS422 converter ?

Posted by: Shane at April 27, 2010 9:56 AM | Reply

Nice, no longer is there a need to specify; "You need a laptop with a serial port" or the tiresome act of warning people that if you buy that db9-usb adaptor from Best Buy and it doesn't work...you're stuck with it.

We always had great success with the db9-usb adaptor from Sea Level, though they were $90US/ea.

Posted by: Terry at April 27, 2010 3:26 PM | Reply

If this converter is not galvanically isolated in both directions then its use in a marine environment could prove to be both problematic and costly.

Ground loops between PC/laptops and NMEA 0183 networks are quite easy to create and without isolation they can result in poor communication when small, and real damage to the PC/laptop when larger, or when used for a long period of time.

Isolation is the only way to guarantee good communications and no risk of damage.

Posted by: Andy Campbell at April 28, 2010 7:49 AM | Reply

The product now appears on the Digital Yacht website under PC Accessories, and it seems that the entire USA website is just a redirect over to the UK site.

Of course the product is more than just a standard USB to Serial adapter, there are also the NMEA differential drivers and (hopefully) opto isolation between the USB serial chip and the NMEA line drivers.

The description on the website does not specify opto isolation but most such devices include it. It would be nice if they included a bit more technical details on the website description.


Posted by: Chris Ellingsen at April 29, 2010 11:52 AM | Reply

Just to avoid confusion, Digital Yacht, Cactus Marine and Marine Electronic Services (Bristol UK) are all part of the same group.
The US Division operates out of Newburyport under the Cactus Marine name but it is a recent startup.
MES has the biggest name in the UK and handles all DY stuff,
Cactus USA are Here:


Posted by: steverow at April 30, 2010 9:37 PM | Reply

Nice catch Evan,

Looking more at the FTDI site I found this:

Isn't that this device?

The FTDI site has a good data sheet, including schematic: http://www.ftdichip.com/Documents/DataSheets/Modules/DS_USB_RS422_CABLES_v120.pdf


Posted by: Al Thomason at May 1, 2010 9:05 AM | Reply

Great find - that proves that DY are just re-badging an FTDI product, and more importantly there is absolutely zero opto-isolation. I didn't think it was physically possible to fit all the required opto-isolators in to that tiny mould.

There is no way any sane person could recommend use of a non opto-isolated USB adapter product in a Marine environment.

Posted by: Andy Campbell at May 7, 2010 12:30 PM | Reply

I am not positive they are using the FTDI product or not, but it is a distinct possibility.

It is possible to fit the opto-isolation in that size of package if you are using surface mount technology. The miniaturization of components with surface mounting on four layer boards is absolutely amazing. Having said that, I have no idea whether they have opto-isolation in their product.

For my own use, I have opto-isolation (not surface mount) components on the board that I connect the FTDI cable to, and then I have connectors that lead out to my marine equipment. Very simple circuit.


Posted by: Evan at May 9, 2010 4:57 AM | Reply

p.s. I did review the schematics and component datasheets for the FTDI product ( http://www.ftdichip.com/Products/EvaluationKits/USB-RS422.htm ) this resembles, and there are no opto-isolation circuits in the FTDI product.

Posted by: Evan at May 9, 2010 5:15 AM | Reply

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