Simple DTMF Microphone MOD FM900

Simple DTMF Microphone MOD FM900

Thankyou to John VK3HJQ for emailing in this article.

As you all know we now have EchoLink on VK2RAY 2mtrs thanks to Ron VK2TRL.

So I needed to add a DTMF microphone to my old Philips FM900 (FM92 remote) that I run in the car so as to control the new VK2TRL-R/VK2RAY EchoLink node, I found an old DTMF microphone that I had laying around (supply voltage for most DTMF Microphones is usually between +8 to 12v) and wired it into the 8 pin socket connector on the back of the control head (as per the wiring diagram below), the only mod I had to do was find some supply voltage for the microphone in the control head, there was +9V available on pin 5 in the D15 connector, so I wired this pin to pin 8 (which was not used) in the 8 pin socket connector to power the DTMF Microphone , simple.

I hope someone else finds this useful.

John VK3HJQ (22/02/2016)


  • Phillip, VK3DCZ

    Now we’ve got echolink on VK2RAY, what a great idea to allow access to the node!
    Cheap DTMF microphones can be found online.

  • Hi Phil,

    Thanks for your comment.

    The mod is so simple, and you are right, DTMF microphones can now be found on the net very cheap these days.

    John vk3hjq (EL1262)

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