DM4000 series accessory connector pinouts

  1. Pulling pin 17 to ground will activate PTT function, activating the auxillary microphone input.
  2. Receive Audio is a fixed level (independent of volume level) received audio signal, including alert tones. If the radio is operating in analogue mode, flat or de-emphasis would be programmed by CPS. Output voltage is approximately 330 mVrms at 60% of maximum (or RSD in analogue mode).
  3. When configured for off-hook, pin 19 is used to detect when a rear microphone accessory is taken off-hook, to override PL and alert the user to busy traffic prior to transmitting.
  4. This microphone signal is independent of the microphone signal on the front microphone connector. The nominal
  5. The Rear External Microphone Input level is 80 mVrms for 60% of maximum level. The DC impedance is 660 ohms and the AC impedance is 560 ohms.


  1. Hi, Is it possible to control Front (Inbuilt) speaker volume and Speaker connected to through rear accessory connector independently.


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