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Remote Speaker Microphone

This BT RSM is specifically designed for use in Mission Critical environments, where a dependable secure Bluetooth connection is a must. Maximum flexibility is provided through additional programmable buttons and both earpiece and headset connectivity. The BT RSM is ready for any scenario.

Engineered to specifically meet stringent Home Office ESN requirements, it replicates familiar TETRA controls for ease of user adoption. As well as UK HO ESN readiness, Sonic’s BT RSM can be programmed to meet the interface requirements of most PTT over Cellular (PoC) applications.

A single rotary Volume/Talk Group select knob provides immediate control, whilst the EMERGENCY button is easy to find when the need arises.

Fully waterproofed to IP67 standard the Sonic BT RSM is designed to take the operational punishment expected in front line services, allowing smart devices to stay protected in pocket or pouch. A wide selection of earpieces and headset options as well as remote PTT units make for maximum flexibility and deployment in multiple roles.

Calibrated microphone sensitivity and class-AB power amplifier make the Sonic BT RSM operationally effective in any environment.

Programmable Function Buttons add role specific controls from Whisper Mode, RTS and ANS/REJECT and END of VoLTE calls.

The unit is also available as a wired USB version for those not requiring Bluetooth wireless connectivity.

Features & Specifications

  • Talk Group Selector with volume control

  • Large PTT Button

  • Emergency Key

  • 2x Un-Assigned Button Function

  • Superb receive audio quality

  • High quality microphone with immunity from GSM/TDMA noise

  • Weight: 210 grams 

  • Operating Temperature: -30 °C to +70 °C

  • Moulding: Black ABS

  • Size: 81×65.5×32 mm

  • Cable: USB C Coiled Cord (black polyurethane)

  • Cable Pull: 30 lbs

  • Bluetooth v5.0 or USB Interface With Full-Speed Transceivers

  • Antialiasing filtering

  • Class AB audio amplifier to drive Loud Speaker

  • Power: 3.3V DC

  • Standby Current: 250 µA

  • ADC,DAC mode + Vol Max Current: 10 mA

  • Power Amp Output: 2.4 Watts

  • Battery Type: 1000 mA/Hr Li-ion

  • Depth of Charge: 80% after 500 charge cycles

  • Battery Life: 1000 cycles (If properly charged/ discharged)


Microphone Specification

  • Type Electret Noise Cancelling Sensitivity: -44dB +/- 2dB @ 1KHz

  • Frequency Response: 100 to 5 KHz (-8dB)

  • Operating Voltage: 1.0V to 10V

  • Impedance: 2K2 ohms


Speaker Specification

  • Type: Mylar Moving Coil Impedance: 4 ohms @ 1500 Hz

  • Sensitivity (1kHz): 95 +/- 3 db

  • Max output: 2.5 W

  • Frequency Response: 100 to 5.4KHz

  • SNR: 104 dB

RSM EEI APP

Sonic’s ESN External Equipment Interface (ESN EEI) is a NATS approved partner application to the RSMs, adding functionality to the Programmable Function Buttons as well as providing an LED blackout option (Dark Mode), useful interface and battery status information.


The transmission of pre-selected Operational Status Messages (OSM) and the ability to ANS/END or REJECT an incoming VoIP or Secure Full Duplex call from a single button press render the RSM and EEI combination an essential tool in operational communications.

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