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FMS Interface |
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276-2009 NPN 2222a Transistor (Many NPN transistors will work)
271-1126 1/2 watt 5% 10k-Ohm Resistor pack of 5
276-1547b 25 Position Male D-Subminiature Solder-type connector
276-1536 Shielded hood for DB25 connector
274-020a 6-Pin DIN male plug (For FUTABA connections)
???-???? You also need some 5 ft. wires of course
(CAT-5 would work nice - I used speaker cable!)
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Total cost: Around $10 - $15
It's come to my attention that the DIN connector has been discontinued
from radio shack. Special thanks to Laurance Ford for finding an alternate
on-line source, Jameco. Here are the parts required from Jameco.
Item P/N Price
6 Pin DIN Plug 15886 0.59
D-Sub Solder Cup Conn 15114 0.49
D-Sub Metalized Hood 15106 1.39
Small Signal GP Transistor (PN2222A) 178511 10 for .16
The resistor is only sold in bulk and would be cost prohibited.
As far as I can tell Radio Shack is the best source for these.
Cat-5 cable or any shielded cable can be purchased from many hardware stores.
Note: If your NPN2222a does not look like mine, here is a
picture of some various compatible ones,
looking from the bottom (wire-side) up.
Here are some random links to other interface tips I've found on the web. When I find a combination that works flawlessly and put it togeather, I'll update this page with more detailed building instructions.
Rick G designed a very simple
hardware interface to connect your transmitter to the printer port of your
computer. The best thing of all is that it also works with FMS! I have made
this page off of his simple schematic and have only tested it with a futaba
transmitter. Here is the design of the transmitter interface: (This particular
design will not work with JR, see link above.)
This was my first test, it worked but was obviously difficult to use since I had to jab the ends of the wires into the appropriate holes of my parallel port each time I wanted to use it.




This is a much more polished version of the same thing. Here you can see that I've soldered the transistor directly to the leads of a parallel port connector. I also bought a 6-pin DIN connector for my trainer jack, note that I shorted the two right pins.





The futaba trainer cord has a short in it, this probably tells the remote that there is a trainer cord connected. You may (I have not proven this) need to connect a wire where the green line is shown if you don't have a real cable.
DOS interface test utility Use this to test your interface, you can run it while in windows. It won't apear to do anything until you get a signal - where it will start couting like crazy and all the bar graphs should become linked to the channels of your remote.
In order for the test program to work, your transmitter must be in standard FM mode (NOT PCM) and your parallel port must be set to use Printer Port IRQ 7 and I/O Port 378h. These settings must be set in the BIOS Computer Setup which you usually access by pressing F1, F2, F10 or DEL key just after your turn your computer on, not in Windows, however after you change the setting in the BIOS you may need to remove the parallel port from the Windows Device Manager (System in Control Panel) and let Windows redetect it with the new settings. This is the default setting used on most computers. Also, this is NOT what FMS defaults to, you must manually set the lpt port to 378 inside the fms transmitter settings for it to work.
Also, if you have a PCI Soundblaster (and maybe other soundcards?) you may need to disable sound blaster compatibility in the device manager. I recently upgraded sound cards to a PCI and my interface would say "signal detected" but not show any movement. When I disabled the soundcard's SB Emulation it worked fine. Thanks to Simon on my forum who figured this out.
As you can see, I put the thing together and it really does work! It also is very simple to put together, obvioulsy.
On the futaba transmitters, the signal is the top-left pin when looking at the trainer jack (Pin 2) and the bottom middle / outer casing is the ground.
The only problems I noticed were that it was slightly "twitchy" meaning it was like I was getting radio interference. You can fix this by having shorter exposed leads and shielding the wires I'm told. It was not TOO twitchy to use so it's still a great tool and the little random acts help hone your skill of inputing the correct movements. Kind of like turbulance!
I got this e-mail about some confusion about this page. I think some of the content can still be useful but this e-mail is pretty straight forward as to some confusing aspects of this page and should help clear up some questions...
From: Eric Wenger [mailto:wenger@ci.okc.ok.us] Sent: Thursday, January 25, 2001 1:34 PM To: eriq@net-express.com Subject: FMS Interface Page - Comments I just wanted to let you know that you have a great page that offers lots to many different modelers. One of the best links that I refer other most often is the construction of the FMS interface cable. I have a couple comments regarding the article, as some of it seems confusing. I constructed my own cable just over a month ago from your webpage without any trouble. However, I have received several comments from others, also constructing cables, that are having a little trouble. I would recommend that you remove the schematic diagram that was recently added. There is much confusion about the battery connection, especially since it is not needed. Also, the schematic is not fully labeled showing pin numbers and such. I would also recommend removing the first photo under Generic Interface. The photo is good, however, it is upside-down from the other photos shown on the page. For those who are not careful, it is easy to connect the wrong wires to the wrong pins on the parallel connector. Keeping your actual construction photos is all that is needed to successfully construct the interface cable, and I think these should be all that is shown on the page. If I had only one comment on your photos, it would be to show that the transistor is installed with the flat side down and the parallel connector is also shown upside-down. Thanks again for a great site! I hope that you will receive these comments, just as comments and not as criticism. Keep up the great work! Eric Wenger ~~~~~~~~~~~~~~~~~~~~~~~~~ Eric Wenger wenger@ci.okc.ok.us ~~~~~~~~~~~~~~~~~~~~~~~~~
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