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MFJ-1272M Instruction Manual
This means that the labels on the MFJ-1272M printed circuit board are backwards
for the Icom radios, such as the IC-2340, IC-2350, IC-281H, IC-2000H, and IC-706.
This also holds true for the Radio Shack HTX-212 VHF transceiver.
For example, MIC audio is designated as pin 6 in the ICOM IC-2340 manual, but
on our MFJ-1272M board it is pin 3, so R3C and M3B have jumper clips on them.
All other pin designations for the Icom and Radio Shack radios are also backwards.
Connections
Connection of the MFJ-1272M is very simple.
Connect your radio's microphone to the microphone connector on the front
1.
panel of the MFJ-1272M. Make sure that that you hear a "click" when the
microphone snaps into place.
Connect the gray, 8-pin MIC plug, which exits the rear of the MFJ-1272M out
2.
of the TO RADIO slot, to the microphone jack on the radio.
Connect the TNC cable, which exits the rear of the MFJ-1272M out of the TO
3.
TNC slot, to the TNC.
External Receive Audio Connection
If you have a radio without RECEIVE AUDIO on the microphone connector, you will
need to perform steps 4 and 5.
Connect a cable from the headphones or speaker out jack of the radio to the
4.
AUDIO IN jack of MFJ-1272M. The AUDIO IN jack on the TNC/MIC switch
requires an RCA male phono plug.
Connect a speaker to the EXT. SPKR jack on the back of the MFJ-1272M.
5.
The EXT. SPKR jack requires a 3.5mm mono plug, with the tip being positive
and the sleeve ground.
10
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