motorola PMMN4050 Noise Cancelling Remote Speaker Microphone User Guide



Product Safety and RF Exposure Compliance

C a u t i o nBefore using this product, read the operating instructions for safe usage contained in the Product Safety and RF Exposure booklet enclosed with your radio.

ATTENTION!The RSM, when attached to the radio, is restricted to occupational use only to satisfy FCC RF energy exposure requirements. Before using this product, read the RF energy awareness information and operating instructions in the Product Safety and RF Exposure booklet enclosed with your radio to ensure compliance with RF energy exposure limits.For information regarding radio use in a hazardous atmosphere, please refer to the Factory Mutual (FM) Approval Product Listing, which is included with radio models that offer this capability.


The PMMN4050 Noise Canceling Remote Speaker Microphone (RSM) provides convenient means of communicating by having a speaker, a microphone, and a PTT in a single, hand-held or clip-on accessory. The RSM includes a noise-canceling port that reduces background noise from the environment during transmission. It can also be used in a quiet environment with NO performance degradation. It also includes a 3.5 mm audio jack to accept a secondary receiver audio accessory.


Attaching the RSM to the Radio

  1. Attach the RSM UC connector to the mating radio side connector and then secure the connection screw in a clockwise direction until tighten.
  2.  The radio will display “IMPRES (TM)” Accessory” and/ or annunciate an alert tone.

Wearing the RSM(See Figure 1)For optimum Noise Canceling performance, there are two recommended methods on how to use the Noise Canceling RSM.

  1. The RSM should be worn at your shoulder as shown in Figure 1.DO NOT cover or block the rear opening at your RSM back housing to prevent performance degradation. For instance, wearing the RSM at chest or abdomen will block the rear opening. When this happens, noise from the environment will not reach the front and rear opening of the RSM in an equal manner. As a result, the performance of your RSM will not meet the Noise Canceling specification.
  2. The RSM should be hand-held 2 inches away from your mouth. The noise-canceling performance of this method is almost comparable to method 1) above.

The combination of radio, RSM, and/or secondary accessories should be worn properly as such the RSM cord would not cross over or touch either the radio’s antenna and/or secondary accessory.ReceivingWhen the RSM is connected to the radio accessory connector, the radio’s speaker is muted, and the audio is only heard from the RSM speaker. Similarly, when a secondary receiver audio accessory is plugged into the 3.5 mm audio jack, audio to the RSM is rerouted to the secondary accessory.TransmittingTo transmit using your RSM:

  1. Press and hold the Push-To-Talk (PTT) button on the RSM.
  2. Speak directly into the RSM.
  3. Release the PTT when finished.Note: Connecting the RSM to the radio does not disable the radio’s microphone and PTT.

Removing the RSM

  1. Unscrew and remove the RSM connector from the radio side connector.
  2. Remember to keep the rubber seal inserted in the RSM’s 3.5mm jack when a secondary accessory is not being used.

Replacing the Coil Cord

To remove the cord (disassembly):

  1. With the front of the RSM facing down, remove the screws from the rear of the microphone using a Phillips-type screwdriver. Retain the screws for reuse.
  2. Remove the rear housing by lifting it straight up and away from the front housing (See Figure 2 below).
  3. Unplug the coil cord connector plugs from the circuit board connector jacks.
  4. Lift the cord with the rubber strain relief out of the front housing (See Figure 3 below).

To replace the cord (reassembly):

  1. Plug the new coil cord connector plugs into the circuit board connector jacks.
  2. Place the new cord strain relief into the front housing.
  3. Replace the rear housing. Make sure that the seal and housings are properly aligned.
  4. Replace the screws into the rear housing and tighten firmly. Do not overtighten.

ACOUSTIC SAFETYExposure to loud noises from any source for extended periods of time may temporarily or permanently affect your hearing. The louder the radio’s volume, the less time is required before your hearing can be affected. Hearing damage from loud noises is sometimes undetectable at first and can have a cumulative effect.To protect your hearing:

  • Use the lowest volume necessary to do your job.
  • Increase the volume only if you are in noisy surroundings.
  • Reduce the volume before connecting the headset or earpiece.
  • Limit the amount of time you use headsets or earpieces at high volume.
  • When using the radio without a headset or earpiece, do not place the radio’s speaker directly against your ear.
  • If you experience hearing discomfort, ringing in your ears, or speeches that are muffled, you should stop listening to your radio through your headset or earpiece, and have your hearing checked by your doctor.


Other than the replaceable cable assembly and clip, the PMMN4050 Noise Canceling Remote Speaker Microphone is not repairable.The following optional accessories and replacement parts are available for order from Motorola’s Radio Products and Services Division (RPSD) or Accessories & Aftermarket Division (AAD).

Part Number Description
4205823V01 Short swivel clip.
RLN6075 Replacement coil cord.
RLN4885 Receive-only foam-covered earbud.
WADN4190 Receive-only flexible earpiece.
PMLN4620 D-Shell Style Receive-only earpiece.
RLN4941 Receive-only earpiece with translucent tube and rubber ear tip.
RLN4760 (S-right)RLN4761 (M-right)RLN4762 (L-right)RLN4763 (S-left)RLN4764 (M-left)RLN4765 (L-left) Clear and comfortable earpieces for use with RLN4941 listed above. These earpieces are alternatives to the standard rubber ear tip and are available in Small, Medium, and Large; for the Left or Right Ear.

Note: Some accessories stated above may have a regional prefix attached to the part number (i.e. MDRLN4885).

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