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[aprssig] TM-271A

Stephen H. Smith wa8lmf2 at aol.com
Thu Mar 10 18:50:11 UTC 2005

scott at opentrac.org wrote:

>Has anyone tried to mod the TM-271A to bring the audio output to the mic
>connector like the TM-261?  Or is that conductor used for something else?
>I just discovered something interesting
>(http://www.mods.dk/view.php?ArticleId=3040)... the TM-271A will clone over
>the air.  So it must have some sort of internal data functions... though
>from the description of how slow it is, maybe it's just DTMF or something.
I've done exactly this with my D700.   I ran a wire from the fixed-level 
RX audio on the MIniDIN-6 "acc" connector to the unused contact on the 
mic jack.  Works perfectly. 

I've done this on many of my older Kenwoods that use the round CBC-8 mic 
connector as well.   Kenwood uses pin  6 on the round connector on some, 
but not all, models for RX audio. There seems to be no rhyme or reason 
to which radios came with audio here and which didn't.  Some models have 
fixed audio here, others have variable levels similar to the speaker 
line.  On the models lacking this connection, I connected a wire from 
the hot end of the receiver audio control pot (i.e. fixed audio level) 
to the unused pin on  the mic jack.

Some diagrams on my website  may be useful. Go to:

Look for the files :
          (Lists the audio level and type (deemphasized or raw discr) 
           on the mic jacks of various Kenwoods.)

     KenMic Plug 8.GIF
          (Pinout of the standard round mic jack on Kenwoods)

     Kenwood MJ-88
          (Shows the correspondence between the round mic jack pinout 
and the
            equivalent pinout on the RJ45 connector.  This is actually 
the diagram
           supplied with Kenwood's MJ-88 adapter pigtail that allows 
older Kenwood
           mics with round plugs to be used with newer Kenwood radios 
equipped with
           the RJ45 jack.

         Standard pinout diagram and notes about the MiniDIN-6 "data" or 
          connector.  This connector is standardized on all radios that 
use it.

Stephen H. Smith             wa8lmf (at) aol.com
Home Page:                   http://wa8lmf.com

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