FMS Forum

by **Daniel** » Mon Sep 03, 2001 7:16 pm

I have an older MC16 (not the MC16/20) and have a 5 wire lead from mainboard to HF which I disconnect and attach to another connector (3.5mm stereo connector -> 3 wires) for use with a CSM interface. Does anyone know what these 3 wires are and which should be connected to what ... trying to build an interface (the one with zener diode and 680 ohm ?)

by **karlmikaze** » Mon Sep 03, 2001 7:50 pm

Hi Daniel,
i just (10minutes ago

finished trying to get exactly your config to run...i'm giving up for tonight.

I found an interesting doc on the mc-16 (old version) hf pin usage:
[url=http://www.bmc.at/helipage/download/verbindu.gif

The]http://www.bmc.at/helipage/download/verbindu.gif

The[/url] rest of the cable is built just as described in the fms manual. Though I'm still experiencing problems...no signal. Tried all different parallel port settings/modes (epp,ecp,spp via Bios), checked on my laptop as well - but nothing worked.

I might exchange the 680 Ohm by a smaller 470 one...maybe that works - it was reported that it did with some Robbe transmitters.

In case you get a working design, please email me at karl.mikaze@web.de!

Hope to get this straightened out :-)

Bye, Chris

by **Daniel** » Tue Sep 04, 2001 4:22 pm

OK, I was wrong from the start ... it is not a 5 wire lead but 4 wire (I need a recount ... 1-2-3-4 ... yep 4), and the stereo 3.5mm plug seem to be at the end of the CSM interface, but at the side of transmitter it is a mono 3.5mm plug.
I found the hard way what pin configuration it was, but it does indeed fit the above mentionned gif for the MC16.
I also found that the info at
doesn't seem to be correct as it refers to pin 1 and 4 ! But this might be for the newer MC16/20

I 'll continue the research and let you know how it goes.

by **Daniel** » Thu Sep 06, 2001 5:49 pm

Finally found the time to buy the required components and built the interface. I found an easy setup without transistor at

which does use an extra diode in parallel on the resistance ... of course I bought al possible components to try to build different interface (with zenerdiode, with transistor, this, that ...) in case one interface would not work.
I started with the one from the wildorf site ... with a 680 ohm resitance, a diode in parallel and a zenerdiode.
Did the test with INTTEST ... OK
Started the FMS ... OK.
So, now I have a lot of spare components left, as the first setup I tried really worked very well.

Hope this might help others

Daniel

by **Daniel** » Fri Sep 07, 2001 6:53 pm

The interface I build works, but only on an older Pentium MMX 233Mhz.
As soon as I try it on other computers (Pentium II and III) it doesn't work anymore. Even changing the printerport settings in the BIOS.
I even tried other interface (with transistor and a 10K resistance on pin 10 and 18, or transistor with 2k2, 200k and 100k resistance using pin 10, 16 and 18)
All work on the older pentium, but not on the newer machines ... must be something with the printerport.

I am out of ideas right now.

by **bsergeev** » Fri Sep 07, 2001 7:43 pm

If the newere PCs have SoundBlaster, disable Printer IRQ Sharing in SoundBlaster's properties.

by **Daniel** » Sun Sep 09, 2001 9:16 am

Both newer machines do not have any soundblaster hardware

by **Daniel** » Mon Sep 17, 2001 7:15 pm

Made a serial connector, works on the PII (win98)... but the PIII has win2k installed, so no transmitter support.

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