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.

  2. Hi Wayne, it it possible to purchase the Universal Connector for use on handheld radios? I have some accessories I wish to convert to use with DP3600/DP4800 radios and lack a source of the actual connectors other than butchering existing accessories? As Motorola sell the rear connector for the DM4xxx series I was hoping the same would be for handhelds (or other radios that use the same connectors like the XPR/APX/MTP850S). I've seen people like Riedel communications use them on their aftermarket custom headsets etc so from that I'm assuming that there must be some source for them?

    I'm happy to go through a Motorola partner once I have a part number, but I normally get knocked straight to the bottom of the waiting list when it comes to requiring a part that's obscure etc.

    Thanks for your time,

    1. The accessory connector for portables is not available as a part from Motorola. Portable radios are not designed/intended to be connected to non-approved peripherals.
      There is a telemetry cable for the DP4000 series that might work - I don’t have the part number handy at the moment. I seem to remember another cable that had open ended wires on the other end - this might work too. I don’t think there’s anything like this for the TETRA/P25 radios.
      If a company is doing something, they’re doing this on their own (suo periculo) and are either butchering an existing accessory or have managed to find something somewhere.

  3. Wayne,
    Many thanks for getting back to me so quickly.

    Ok (so for anyone else reading) I guess the options are: RLN6075A [RSM Replacement cable] or PMKN4040A [portable telementary cable].

    My main concern is if either are shielded. I’ve use a (non-Motorola) cheap RSM and recabled a Peltor noise cancelling headset with it, sadly this suffers from the DMR RFI noise, even with a couple of inductors in line due to lack of shielding in the cable.

    My original plan was to use a connector and some good shielded heavy duty cable (with some extra cores for Multi-PTT).

    Still, I’ll have to look at those cables or another source, I guess it’s all part of the fun!

    Again, thanks for a quick reply Wayne and all the best!

  4. Hi Wayne, Is there anyway I can use the rear accessory port to use too DM units to bridge two networks together? Say a UHF and VHF digital MOTOTrbo net?

  5. Sort of. Using two mobiles back-to-back works okay but the audio is not that great since it gets converted to analogue then back to digital in this case. I would say that a RICK is needed (HLN3333) to manage the logic and audio levels. This would also only support a single talkgroup and audio only. I’ve never tried this setup myself so YMMV.


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