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Microphone Wiring

We created this page to help people understand that not all microphones are wired the same way. For example, just because two different microphones are 4 pin does not mean that they are wired the same, even if they are the same brand! Different manufacturers may wire their microphones differently. Generally, a radio manufacturer will wire their microphones the same so that the microphones are interchangeable between their radios, however, this is not always the case.

For example, Cobra 4 Pin radios are wired 1) Shield 2) Audio 3) Transmit 4) Receive while Midland 4 Pin radios are wired 1) Audio 2) Shield 3) Receive 4) Transmit. There are some radio brands that have the same general wiring (such as Cobra and Uniden) but that is not always the case.

The list below offers some microphone wiring information. Mic wiring can be frustrating enough, but when you can't find the right wiring info, it is just impossible. We will continue to try to get all the information that we can listed on this page.

Radio Mic Wiring Diagram

CB Microphone Wiring (Galaxy)

The chart and image above are correct for these models:

(Extra NOTE: The popular Astatic 636L-DX1X is compatible with these)

Galaxy CB Radios

  • DX919
  • DX929
  • DX939
  • DX949
  • DX959
  • DX979
  • DX44V
  • DX55V
  • DX66V
  • DX77V

Cobra CB Radios

  • 19 DX IV
  • 148 GTL
  • 18 WX ST II
  • 19 DX IV Camo
  • 25 LTD
  • 25 LX
  • 25 NW LTD
  • 25 WX NW ST
  • 29 LTD Chrome
  • 29 LTD Classic
  • 29 LTD DE
  • 29 LX
  • 29 LX Camo
  • 29 NW LTD
  • 29 WX NW ST

Uniden CB Radios

  • PC68LTW
  • PC68XL
  • PC78LTW
  • PC78XL
  • PRO505XL
  • PRO510XL
  • PRO520XL

Midland CB Radios

  • 1001LWX
  • 5001
  • 9001Z

Wiring for the C29 LX MAX and the C29LTDBT:

  • 1) Ground
  • 2) Audio
  • 3) Transmit
  • 4) Receive
  • 5) BT Button
  • 6) BT Microphone


Pin-End Views

Cobra 4 Pin Mic Wiring Diagram
Cobra 4 Pin


TX = White, MOD = Red, REC = Blue, Shield/Common = Braid/Black

Midland 4 Pin Microphone Wiring Diagram
Midland 4 Pin
TX = ?, MOD = ?, REC = ?, Shield/Common = ?
Cobra 5 Pin Microphone Wiring Diagram
Cobra 5 Pin


TX = White, MOD = Red, REC = Blue, Shield = Braid, Common = Black


Wiring Color Codes for Astatic 6 Wire Microphones:

  • White - Audio
  • Shield - Ground
  • Blue - Common for Switching
  • Red - Push to Talk (Transmit)
  • Black - Receive
  • Yellow - Receive Ground (not normally used)

NEW information - 6/26/18

6 Pin President Microphone DNC520 Microphone Wiring:

1. Modulation
2. RX
3. TX (Up/Down)
5. Ground
6. Power Supply

DNC520 Microphone Wiring Diagram

Having troubles with your microphone?

  • Make sure the connections are tightened.
  • Ensure that the microphone pins on the radio are making a connection with the microphone plug.  If need be, you can very gently spread the pins with a small flathead screwdriver.
  • Make sure your CB mic is plugged in securely. Check for breaks or damage to the plug and cord. Check the pins in the radio for damage as well.
  • Be sure you are pressing the CB microphone button all the way in.
  • If it is a power mic or echo mic, make sure there is a battery in it!
  • Visit our Troubleshooting Radios Article for other helpful information.


Thanks for all your help on wiring. so helpful having someone put all this effort online.
Dear Sir, Could you please confirm the pins on a 4 pin Uniden PC-122. I have looked on the internet and the results agree with my Red Devil Microphone. Though when I plug the Red Devil in. The radio goes into transmit. If I press the PTT I then have audio modulation. If I use the original Uniden Microphone which came with the radio. All is fine. Kind regards, Paul.

COMPANY RESPONSE: We believe that both the Uniden PC122 and the RD104E-4B are wired 1) Shield, 2) Audio, 3) Transmit, 4) Receive. With your results, it seem like the microphone was rewired. Was the Red Devil Microphone that you have brand new or could someone have rewired it?

I have a superstar 121 works fine but the mic is a trucker series tm-2002. When I key up every body says all they hear Not a loud high pitch but squealing when I key up.
I have a Ronald 10 meter radio. I want to install a Road King 56. Can anyone tell me the pin wiring and wire color. Thanks
Hi, I have a K-PO DMC 110 and need the wiring diagram for a CRT SS6900N, can anyone help.

Thanks in advance.
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