Quality NMEA 2000 cabling, the eBay way

Ben Ellison

Ben Ellison

Panbo editor, publisher & chief bottlewasher from 4/2005 until 8/2018, and now pleased to have Ben Stein as a very able publisher, webmaster, and editing colleague. Please don't regard him as an "expert"; he's getting quite old and thinks that "fadiddling fumble-putz" is a more accurate description.

32 Responses

  1. Ben Ellison Ben Ellison says:

    Wow, that was fast. The “surplus surplus” Thin cables have already been spoken for by reader John T here in Maine.
    Which reminds that how poor I’ve been at promoting Panbo Classifieds. It’s true that there aren’t many listings for used gear there, but there really should be. The rate of sales for what has been listed is pretty impressive, plus the ads are free and the listing process is easier than eBay or Craigslist, I think. Please see if Panbo Classifieds can’t recoup some of your electronics dollars!

  2. I won’t be so bold as to claim spotting a mistake, but I don’t see where your buss terminations are? Surely your wind instrument and rudder sensor aren’t terminations themselves, are they?
    Is the short yellow “1m” wire the power feed?
    I’m sure glad my system is a bit simpler than yours..:-b

  3. Ben Ellison Ben Ellison says:

    Hartley, there are inline terminators at each end of the backbone. Maretron and Garmin sell them in Micro size, and there may be others. They’re kind of nice because you can add another drop to them (up to 6 meters). Incidentally, N2KBuilder would not have validated the backbone without terminators.
    Yes, the powertap is yellow.

  4. Adam says:

    Great post, Ben! Remember when I advocated getting DeviceNet boxes like these on eBay…four years ago? 🙂
    But in all seriousness, they worked great on the good-sized NMEA2000 network on our Nordhavn and were 100% reliable from day one.

  5. Adam says:

    Hm…probably should have clarified that I was referring to my forum comment here:

  6. Jack Van Vooren says:

    Great Article. Thx.

  7. OK, Ben – I figured there had to be, but the diagram doesn’t make it easy to figure out where they are. The green line running through is confusing to me – it is partially on the Buss and partially on a spur, at least to my eye. I guess I should familiarize myself with the software..:-)
    But it sure looks a lot neater than the hand-drawn diagram I have for my MUCH simpler RayMarine system. I may see if I can use it to diagram my stuff and consign my scribbled drawings to the history file.

  8. Ben Ellison Ben Ellison says:

    Sorry, Hartley, but I’m glad you’re confused as it makes a point. The green line is what N2KBuilder sees as a valid backbone/trunk, and I agree. You’re seeing green on spur/drop/branch lines only because you’re used to the notion that backbones run straight thru Tees. CANbus/N2K doesn’t actually give a hoot about that. The backbone is simply the continuous network cable that has terminators on each end. It can carry data at least 100 meters over decent DeviceNet Thin cable and Micro connectors.
    By the same token, N2K branches can be looser than normally depicted. They can go straight off a Tee, and/or include multiple Tees or a junction box. The only limit is that no device on a branch/drop/spur can be more than 6 meters from the backbone. That’s the only design error that N2KBuilder highlighted in red.

  9. Thanks, Ben! I do understand the architecture of a CAN buss, but some of the graphic conventions of the diagram have me guessing. If I understand correctly, you’re telling me that the two buss terminations are located at the WSO100 wind instrument and in the connector inline with the cable to the RAA100 rudder sensor.
    You are absolutely correct that my familiarity with the RayMarine hardware layout makes it tricky for me to understand – the devices to do what you’re doing there simply don’t exist in Ray hardware, though you could get fairly close.
    I’m also thinking that the rather convoluted and overlapping sections in the lower center (surrounding the new devices you describe) are probably a pretty good representation of what is likely a serious nest of snakes..:-) Sounds like a good reason to label both ends of every cable.

  10. tim says:

    Wow, that’s some network Ben! What’s your bus utilization with all of that running?
    Have you tried using the snap feature in N2KBuilder? It might clean up your funky overlapping cables a bit.
    Personally, I prefer to run the bus through those Turck boxes which have an in and an out since electrically it keeps the network looking more like a bus and less like a tree. I don’t think that violates the NMEA standard that says the network must not be routed through a device anymore than a tee would.

  11. Robert McAllister says:

    The only problem I see is the lack of a Maretron Alarm handler on the right hand (24/7) side of the network – your ALM100 and SMS100 will need to be told when to send alerts – Unless you are planning on doing this through the IPG100?

  12. Ben Ellison Ben Ellison says:

    Thanks, Robert, but the powertap is that black box with short yellow cable at about top center. The SMS100 and one ALM are on the right side 24/7 leg, and should be able to work with the sensors on that side. Come to think of it, though, there probably has to be a DSM on that side to be the brains for alarms.
    However, I have not yet figured out how to split the powertap cleanly and it may turn out that this whole network doesn’t use much 12v juice, especially when most of the screens are turned off. This is a work in progress 😉

  13. Robert McAllister says:

    Yeah thats what I meant about an alarm handler – a DSM to tell the ALM100 to make noise, and the SMS100 to send text messages, and then, perhaps more importantly to clear the alarm and stop the noise!

  14. Electronics Diva says:

    While I applaud any way to save a buck and still get the same results as buying the high priced spread, I am always a bit concerned about Ebay and low prices. My understanding is that Devicenet made industrial and not marine applications, if so care is needed in using these. Are these items NMEA certified? If not there is a potential for impedence mismatching and functionality issues with the network. Also what kind of warranty do they have. Maretron has a 2 year warranty as do other marine oriented manufacturers. Then there’s always the Chinese “knockoff”. Which we all know may or may not be the same quality as the original. These have a tendency to be sold on Ebay. So let the buyer beware.

  15. Adam says:

    @electronics diva,
    NMEA2000 is a multipart standard that includes requirements for physical cabling as well as electrical and networking protocols. The physical cabling standard is the same as DeviceNet.
    Warranty obviously varies by supplier and depending on whether you are buying new or used, but given that these are fixed devices with no moving parts, power supplies, or circuit boards, I think the failure risk when properly installed is very low.
    In our case, as I mentioned above we installed eBay-supplied Allen-Bradley 4-, 6-, and 8-port hubs on our 30-device NMEA2000 network with flawless results. The network was tested over 3 years and 11,000+ miles of power cruising.

  16. Ben, I went to the link you included, and requested the info for downloading the N2KBuilder program – but I never heard back from Maretron. Do you have to be on their customer list to get access?

  17. tim says:

    Hartley, you should have gotten the download email in a minute or so of requesting it. Request again and check your spam filter.
    TBH, I’m not sure why they bother with this step at all. I’ve probably downloaded N2Kbuilder a dozen times and I’ve never gotten so much as a new product announcement email from them.

  18. Hi Tim, well, I just tried it again, using two different email addresses – and nothing (including the spam catcher here and the one at my email servers). I guess something really doesn’t like that email!

  19. Kudos and a big THANK YOU to Mark Oslund of Maretron, who send me a personal email with the instructions on downloading N2KBuilder!! I have no idea where the official emails were being scraped off, but I have everything now, and I’m looking forward to trying it out.

  20. FatDash says:

    Looking at your design for the N2KBuilder you are using Maretron 4-drop Micro Multiport boxes. These have a male jack on them so you can use a standard N2K cable that is M/F. Using the Turck JBSS 57-811 it has all female ports.
    Are you making all your own M/M cables?

  21. Adam says:

    I don’t know what Ben used but in cases like that the Maretron field-attachable connectors (FACs) can be used to sort out the cable gender issues. Or, if you don’t want to go through the hassle of using a FAC (NMEA2000 micro wires are tiny) or are concerned about reliability, Actisense has 10″ gender changing cables, which run about $20:

  22. Ben Ellison Ben Ellison says:

    Hello FatDash,
    Adam is quite correct but there are other ways to use the Turck JBSS multiport. My install looks something like the last photo. The backbone is Mini not Micro cable with a Mini power tap tee’d in. One JBSS is simply inline with the backbone using its Mini male and female ports. The other JBSS is dropped from the backbone using a Mini cable. Thus all 8 female Micro ports on each JBSS is available for device drop cables. I explained in the last paragraph that I couldn’t quite model this in N2KBuilder, but got as close as possible.
    I believe it’s also possible to use just the Mini female ports on a JBSS without resorting to field-attachable connectors or a gender changing cable. Use one port for the power tap and make two others backbone connections, (or just screw male terminators into them if a 5 device network is all you need).
    Note that the standard Maretron Micro powertap tee also has female connectors for both backbone connections. It can be a hassle if you have to move the power tap but the idea is that even if you break open the network when it’s hot you’ll never expose hot male 12v pins. Similarly it would be a bad idea to leave the Mini ports on the JBSS uncapped if you don’t use them. I linked to available caps in the entry, but think it can also be done reasonably well with rescue tape.

  23. Henning says:

    The Maretron Micro powertap tees also are a BIG hassle if you want to use more than one in order to independently power devices on the bus.

  24. Rodrigo says:

    Hi, do you know where can I find simnet pinage description?
    I have bought some Simrad used equipment (IS20 Graph, Wind and Mult), Autopilot TP22 and Radio RS25.
    But now I am suffering a lack of information about connectivity

  25. Ben Ellison Ben Ellison says:

    Rodrigo, Simnet wire colors are almost a match for other NMEA 2000 type cables, so the pin out should be easy to figure out:
    BUT I think it’s a bad idea to cut and splice any N2K cabling if not forced to, and SimNet especially because of its light construction and the fact that the drain “wire” is foil.
    I suggest that you learn how to build a SimNet network and find the bits you need for your system. Some of the links in this entry don’t work any more…
    …but I found it easy to Google up a SimNet manual:
    Better yet, buy the SimNet to male DeviceNet adaptor cables needed to put your gear on a standard N2K cabling system:
    It’s important to learn how any N2K network goes together with powertap, backbone, terminators, and drop lines.
    And there are possibly tolerable exceptions. Note that daisy chaining multiple devices on a single N2K drop — the reason your IS20 displays each have two ports — is not allowed by NMEA but several manufacturers support it and it’s working on many boats.

  26. Ben Ellison Ben Ellison says:

    Learn from my mistakes, Howard; always check the product catalogs, datasheets, etc.!
    I think those are (big) Mini size connectors, not Micro size. Datasheet with dimensions and more here:

  27. Taylor W Fry says:

    Do you have the part numbers used for the terminators for the micro and mini connectors?

  28. Neftaly says:

    You can now find several different mini connectors on Aliexpress for $2-5 under “M12 5-pin”. Check the photos first; most are listed as “aviation plugs”, as the sellers don’t know the difference between Devicenet & GX-12 connectors.

  29. drewc says:

    Ben, can you recommend a specific source for the appropriate Turck M12 DeviceNet 5-pin MALE right-angle cables to fit the JBSS? Looks like you found a couple from your photos. I have been looking and looking on eBay and other places but so far no joy. Lots of FEMALE right angle, straight and 3/4-pin cables, but haven’t found a single correct one for this box. Thanks.

  30. Ben Ellison Ben Ellison says:

    Sorry, no. eBay is obviously spotty, but trying to find these cables without the NMEA 2000 nomenclature is quite hard because DeviceNet actually includes multiple connector types and some companies use completely different names anyway.
    That said, I have some short black N2K cables with metal 90 degree connectors at both ends that are made by LTW. Also, both Maretron and Actisense offer high quality 90 degree male field attachable connectors.
    And Molex seems to have every possible configuration of M12 connectors if you can figure them out and then find a source. Would this work for you, for instance:

  31. Anonymous says:

    Ben, thanks for the options. I think I’ll keep looking for the molded-on connectors and cables as there are many possible sources of surplus Turck components out here in the Bay area (and the field-attachables are $20+ each!)

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