@ Eldorado & Timmy
@ Eldorado
Thanks for the RJ45 wiring info. You confirmed my suspicion about the channels being on TX. Which means there is voltage on TX as well - partial grounding of that voltage is how the channels work.
No offence meant, but I disagree with your last comment.
Why does a Power mic make any difference? The E/R switch has nothing to do with the audio line. It switches between PTT Electronic and Relay switching for the D-104. You said there is no RX, so Relay switching is impossible (RX & TX are connected together). In the Relay position, the radio won't key, it will just change the channel - Which is exactly the problem Timmy is having.
A Cobra 4 pin mic uses Electronic switching. TX and RX are connected to shield/ground, not each other.
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The D-104 has the ability to use Electronic or Relay switching. For models that have a E/R switch, the Blue wire is the "common" on the PTT switch. This is so it can be used with a 5 pin Cobra, etc. which doesn't use shield to switch PTT (it uses a separate ground) or an older radio that uses Relay switching.
For the D-104 to be properly wired for a Cobra 4 pin, the switch must be in the "E" position and the mic plug should be wired (assuming stock colors):
Pin 1 - Bare copper shield and Blue wire (Ground & PTT common)
Pin 2 - White wire (audio)
Pin 3 - Red wire (PTT TX)
Pin 4 - Black wire (PTT RX)
N/C - Yellow wire
The Female 4 pin mic plug on the RJ45 adapter should be wired:
Pin 1 - Black (shield)
Pin 2 - White (audio)
Pin 3 - Red (TX/UP/DW)
Pin 4 - N/C
[USER=64271]@TimmyTheTorch[/USER] - Would you mind popping the base plate off your D-104 and take a picture so we can see what the "New Internals" are. I don't want to lead you down the wrong path if something is not stock. And I don't think it is because your picture of the mic plug shows a Blue wire and shield together. The TUG8 stand with the e/r switch only had 3 wires and a shield (no Blue wire). So something isn't "stock" with your D-104.
Thanks,
Dr_DX
