IC27

FOR THOSE INTERESTED IN AN ALTERNATE METHOD HERE IS WHAT HAS BEEN DONE BY
WB4FOW ON SEVERAL OTHER RADIOS:

SINCE ABOUT 1985 MOST ICOM RADIOS HAVE PIN 8 OF THE MICROPHONE CONNECTOR
WIRED TO THE SPEAKER. THIS IS CONVENIENT FOR THE WIRING OF A TNC
AND IS USUALLY EASY TO MODIFY SO THAT RECEIVE AUDIO IS TAKEN FROM
THE HIGH SIDE OF THE VOLUME CONTROL.

ON THE IC-27/37/47 RADIOS, ON THE BOTTOM SIDE OF THE RADIO, SINCE 
ABOUT 1985 MOST ICOM RADIOS HAVE PIN 8 OF THE MICROPHONE CONNECTOR
WIRED TO THE SPEAKER. THIS IS CONVENIENT FOR THE WIRING OF A TNC
AND IS USUALLY EASY TO MODIFY SO THAT RECEIVE AUDIO IS TAKEN FROM
THE HIGH SIDE OF THE VOLUME CONTROL.

ON THE IC-27/37/47 RADIOS, ON THE BOTTOM SIDE OF THE RADIO, JUST UNDER
THE AREA OF THE SPEAKER,  IS A TWO PIN CONNECTOR WITH A GREEN AND RED 
WIRE ATTACHED. THE GREEN WIRE IS SPEAKER AUDIO AND THE RED WIRE IS +8 VOLTS.

BY CUTTING THESE WIRES AND ATTACHING THE GREEN WIRE TO THE HIGH SIDE OF
THE VOLUME CONTROL  AND  ATTED WIRE TO SWITCHED 12 VOLTS 
A TNC CAN BE WIRED TO JUST THE MICROPHONE CONNECTOR AND MAKES A CLEAN
INSTALLATION PROVIDED THE RADIO IS DEDICATED TO PACKET.

TO GET BACK TO THE SUBJECT OF THE ALTERNATE MODIFICATION FOR THE IC-3200A 
YOU CAN REWIRE PIN 8 OF THE MICROPHONE CONNECTOR TO THE HIGH SIDE OF THE
VOLUME CONTROL AND AVOID THE MUTING CIRCUIT BUT IF YOU PLAN TO LEAVE
THE TNC WIRED PERMENANTLY TO THE RADIO AND ALSO,TO USE THE RADIO ON VOICE
YOU WILL NEED TO CHANGE A RESISTOR IN THE TNC SO AS NOT TO LOAD DOWN THE
AUDIO AT THE VOLUME CONTROL. THE VALUE OF THIS RESISTOR WILL HAVE TO
BE DETERMINED EXPERIMENTALY.

IF ANYONE REQUIRES MORE INFORMATION OR ASSISTANCE WITH THIS MATTER FEEL
FREE TO CALL CLARK, WB4FOW, AT  305-594-4313  MONDAY THROUGH FRIDAY 
10AM TO 6PM OR LEAVE A MESSAGE IN THE WB2WPA OR N4LDG PBBS'S.

GOOD LUCK!