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ContinuousWave: Small Boat Electrical
E-TEC: EMM to Serial RS-232 Cable
|Author||Topic: E-TEC: EMM to Serial RS-232 Cable|
posted 04-12-2009 11:51 AM ET (US)
To connect the EMM of an E-TEC outboard to the serial port of a laptop computer a specialized cable is required. You can obtain this cable as an OEM part, as an after market part, or you can make your own.
The wiring of the cable is as shown below:
E-TEC EMM Cable to Laptop Serial Port
The E-TEC EMM connector mates with a DEUTSCH 3-PIN connector. The most common termination for an RS-232 serial cable is a DB9F connector; this will plug into the serial port connector on most laptop computers.
The wiring of the DB9F is shown in this photograph:
Pins 1 and 4 are wired together. This loops the terminal's DTR signal back to the DCD input.
The rear of the Deutsch 3-pin is shown below. The location of the pin identifier legends is a bit unusual.
The assembled cable is shown here. I used BELDEN 9451 for the cable. Any shielded two-wire cable will be sufficient.
To facilitate easy solder assembly, I used a Deutsch connector with the gold pins with a solid body. These are really designed for a crimp connection, but a special (and expensive) circumferential crimping tool is needed. You can use these pins as a solder-type pin and easily insert the wire and solder it. If you are not electronically inclined you can buy this cable from after market suppliers.
I had the BELDEN 9451 wire, the DB9F, and the DB9 connector shell on hand, and I ordered the DEUTSCH DT04-3P with Solid Pins, Gold, 16-18 AWG.
To clarify, the 9-pin DB series connector I used has socket connections. There is sometimes confusion about which gender this is, male or female. The connector body itself would be considered the male gender, but the actual connector contacts are small socket receptacles, sometimes also considered the female gender. The usual connector on a laptop has pins for the contacts but the connector body is a female gender.
posted 04-12-2009 12:32 PM ET (US)
This cable assembly is useful for owners of an Evinrude E-TEC who have also acquired the Evinrude diagnostic software. While the unregistered version of the software is limited in what functions are enabled, you can use the software to perform some useful tasks. One such task is to download an engine history report from the memory of the engine management module (EMM). These reports give a great deal of information about the engine. A sample of the engine history report is presented in an article in the REFERENCE section. See:
E-TEC Engine History Report
As far as I can tell, the E-TEC engine is unique in this capability, that is, no other modern engine allows for its owner to easily obtain this sort of data from the engine by himself. As far as I can tell, all the other modern engines require that the dealer or an authorized service technician use proprietary tools and software to obtain data from the engine.
I built this cable some time ago, and, as best as I can recall, I did test it with a USB to Serial Port convertor, as the laptop computer I had was fairly new and lacked a DB9 serial connector and port. In the Evinrude software there is a provision, as I recall, for communicating with a serial port via a USB on the computer.
There is a very strong recommendation that when you use a laptop to connect to your E-TEC engine that you operate the laptop from its battery power source and not have any connection to 120-Vac power. If you note in the wiring of the cable, the ground connection of the laptop and the ground connection of the EMM are bonded together. For this reason, it is a very good precaution to not have the laptop plugged into 120-Vac power sources. If there were any grounding problems or wiring problems in the 120-Vac circuit, you could get some unanticipated results.
I should mention that the Evinrude diagnostic software needs the Windows operating system to run. If I get the opportunity I will try running it under the MacOS using VMWare Fusion to enable WindowsXP. It is on the list of small boat electrical projects for this season.
posted 04-13-2009 09:05 PM ET (US)
What's the price on the OEM cable part?
What's the price for the registered version of the software?
[Sidebar discussion about docking stations has been deleted--jimh]
posted 04-13-2009 09:34 PM ET (US)
Chuck--I don't have the MSRP of the OEM cable. I am not sure if it is a regular part. It may be a dealer-only part. I could not locate it at
I don't have a price on the diagnostic software. This also seems like it is a bit of an erratic part. Some dealers sell it to their customers, and some dealers do not. Again, it may not be a regular customer part.
Only dealers can register the software. Once the software is registered it can perform more functions, such as uploading new EMM firmware. That control is reserved for the dealer. The unregistered software can do some interesting functions. I think it can perform several diagnostic tests, such as shutting off an individual injector or temporarily altering some of the injector coefficients, but it cannot make changes to the firmware of the EMM.
I don't recall if the unregistered version can change the oil mix ratio, or not. Maybe someone can chime in on that point.
posted 04-19-2009 07:59 PM ET (US)
I came across a listing of the Evinrude diagnostic cable for sale at $72 from a dealer in Florida under the category of Shop Aids and Tools.
posted 06-16-2009 09:33 AM ET (US)
I tested the E-TEC diagnostic software running under Windows-XP on my Apple Mac Book Pro using VM-Ware FUSION. The software appears to function normally. Using a Keyspan USB serial port, the software recognized the serial port. I did not have a chance to test with an actual motor, but using the loopback test function in the E-TEC software with a loopback test adaptor, the software confirmed that it was operating properly and could send and receive data via the serial port. E-TEC owners who also have an Apple Mac Book Pro or other Intel-processor based Apple Macintosh should be able to use the diagnostic software.
posted 09-27-2009 08:25 AM ET (US)
I have tested the cable I made according to the instruction I give above with several different E-TEC motors. It works perfectly.
posted 03-31-2012 02:43 PM ET (US)
I have fabricated a few cables as I describe above. I am selling them for $, including post paid shipping to USA mailing addresses. Contact me via email if you would like to buy one.
posted 05-22-2012 08:14 AM ET (US)
I have an ETEC 25 and the software. Plan on making a cable. Does the engine have to be running or power applied for the EMM to operate? Thanks
posted 05-23-2012 09:06 AM ET (US)
The EMM is operated electrically from the E-TEC engine power. The ignition key switch must be in the ON position for the EMM to receive electrical power to operate.
Can you send me a digital image that shows the location of the EMM connector on the E-TEC 25-HP engine? I will add it to the article on E-TEC rigging.
posted 05-23-2012 10:22 AM ET (US)
If your motor is a pull-start only, then the laptop will only get EMM information while the engine is running or cranking over.
Evinrude does make a power supply tool and cable to get voltage to the EMM when the motor is not running but key is ON.
posted 10-24-2012 03:03 PM ET (US)
I was out-of-stock on this cable for a while, but I have a new batch just made and ready to go. The price is now $40, but this still includes shipping via U.S. Postal Service PRIORITY MAIL to any USA address. Delivery is usually two days to most addresses.
posted 03-30-2013 01:21 PM ET (US)
I have made a new batch of these cables and now have them in stock. The price is $40. Contact me via e-mail if you would like to purchase one.
posted 04-28-2014 02:51 PM ET (US)
I have made another batch of the RS-232 (DB9F) to Evinrude E-TEC EMM (Deutsch DT04-3P) cables. The price is still $40, including shipping via US Priority Mail. I can only send to USA address that can receive mail from regular delivery. I cannot send overseas or to street addresses that the Post Office does not deliver mail to. Shipping to unusual locations will not be included in the $40 price.
Please note these cables are just wire and connectors. They contain no USB device. I prefer to accept payment via PayPal. Contact me via email to arrange details of a purchase and shipment.
posted 05-22-2014 09:25 AM ET (US)
I have the Evinrude data cable, and it is 10-feet long. Can I extend the length of it to 20-feet so I can put the laptop in the cabin so I can see the screen easier? I have a hard time seeing it in the sun Thanks for your help. This is my first post, and I would like to say Hi to all.
posted 05-22-2014 09:43 AM ET (US)
I recommend you extend the cable and report back on the outcome. The maximum distance for RS-232 communication depends on many variables, including the baud rate, the capacitance of the cable used, and the precise nature of the electrical circuits employed. Because of those many dependencies, it is difficult to promulgate a specific maximum length that might work in a particular situation.
posted 05-22-2014 11:36 AM ET (US)
The easiest way to extend that cable would be to get a
serial cable "extension cord" with male 9-pin connector on
one end and a female 9-pin on the other end.
posted 05-23-2014 05:14 PM ET (US)
There are still several cables left unsold from my most recent production patch.
posted 05-24-2014 03:25 PM ET (US)
I extended the cable 8' so it is now 18' and working perfectly.
posted 05-25-2014 02:18 PM ET (US)
Thanks for the feedback on the RS-232 to EMM cable extension to 18-feet.
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