[aprssig] Kenwood D710 Mic protocol

John Gorkos jgorkos at gmail.com
Thu Nov 10 08:19:22 CST 2011

I'm in the beginning stages of an idea here...
I picked up one of these little gadgets at the local hamfest for $30:

Basically, it's a Bluetooth keyboard almost exactly the same size as my 
Samsung Galaxy smartphone.  It works great with my cellphone, but I want 

My thought is to build a simple microcontroller that sits in-line with 
My D710 mic cable.  It could draw off the 8V line on that connector, and 
have a bluetooth transceiver in it and a pic or avr chip that generates 
the appropriate 'serial' protocol to simulate mic keypad presses.  By 
doing that, I could use this handy little wireless, full function 
keyboard for APRS text messaging.  Normal keypad presses would be passed 
through from the mic, but any keypad presses sent over bluetooth would 
be translated from the character sent to the appropriate serial protocol 
for the mic (including multiple presses, if necessary, i.e. you have to 
hit '2' three times to generate a "C".

Anyway, I was wondering if there are any published specs on the protocol 
that the Kenwood mic uses to talk to the D710.  According to the 
"TM-D710 Instruction Manual" page 15, pin 8 is "keypad serial data."

I'm thinking it would eventually be about a $100 add-on to the radio to 
have wireless keyboard messaging ($30 for the keyboard, and $60 or so 
for the dongle that goes in-line with the mic cable.  Heck, a really 
smart guy would include a standard USB host connector in there too, so 
you could plug in a standard USB keyboard (i.e. one of those rubber, 
roll-up jobs you get for $10 at hamfests).


John Gorkos

More information about the aprssig mailing list