Sonim Introduces First Remote Speaker Microphones with Channel Selector for PTT-over-Cellular Solution that Supports up to 96 Unique Channels

  • RSMs with 10- and 16-channel selectors work with Sonim XP8 and XP5s rugged phones
  • Fully compatible with ESChat PTT service

Austin, Texas (July 22, 2020) — Sonim Technologies™ (Nasdaq: SONM) launched the Stone Mountain Phoenix Epic Remote Speaker Microphone (RSM) with 10-Channel Selector and the Klein Valor RSM with 16-Channel and Volume Selectors that are compatible with the Sonim XP8 and XP5s rugged phones. These RSMs, when combined with the Sonim handsets and ESChat PTT service, provide the first cellular-based PTT solution that lets customers program up to 96 unique channels to the channel selectors on the RSMs.

These ultra-rugged accessories are designed with the first responder and industrial worker in mind, offering a complete hands-free communications experience on Sonim’s handsets. For example, the ability to support up to six zones and up to 96 channels from the RSM channel selector, allows public safety agencies and enterprises to set up users by geography, department or function, providing a form of speed dial for critical communications.

“We are excited to bring an LMR-like experience for the first time to a broadband PTT solution, whether you are on a dedicated public safety network or other commercial networks,” said John Graff, CMO, Sonim Technologies. “We are very pleased to collaborate with Stone Mountain, Klein, and ESChat to bring these unique capabilities to customers that rely on critical communications for their operations.”

Key features of these RSMs working with Sonim’s XP8 and XP5s handsets include:

  • Sonim’s SecureAudio interface lets the speaker microphone be physically secured to and powered by the XP8/XP5s, a capability unique to Sonim devices.
  • The RSMs lets users directly change channels or talk groups and control volume.
  • The solution is available via leading mobile operators in the U.S. and Canada.

The Stone Mountain Phoenix Epic RSM with 10-channel selector meets Sonim’s ultra-rugged, IP-68 and Mil-Std-810G performance standards and is available as non-incendive C1D2. It includes a physical knob to change channels, RampClikTM one-touch volume control, listen-only headset jack and large PTT button. The optional listen-only earpiece jack allows for covert listening in secure, quiet settings. In addition, a built-in emergency button on the RSM is mapped to the Sonim handset emergency button making it easy to initiate lone worker or man-down alerts. Stone Mountain provides a 2-year limited liability warranty. To see the Stone Mountain RSM in action, click here.

The Klein VALOR RSM with 16-channel and volume selectors meets IP-55 performance standards and includes two physical knobs for channel and volume selection, two large PTT buttons (front-facing and thumb) and overmolded rubber for grip. It also has a locking earpiece port for listen-only headsets, which redirects the receive audio from the speaker to reduce noise and dissemination of information to the public. Klein Electronics provides a 3-year limited liability warranty. To see the Klein RSM in action, click here.

ESChat is the leading solution for carrier independent Secure Push-to-Talk (PTT) over LTE communications. ESChat includes AES-256 encrypted PTT voice and multimedia (text and image) messaging. ESChat also provides live and historical (bread crumb) tracking and mapping. Used by all branches of the U.S. Military, as well as federal, state, and local public safety agencies, ESChat is able to operate over and across any wireless network, including all commercial carriers, private 3G/4G/5G networks, and Wi-Fi. ESChat supports standards-based interoperability with LMR radio networks

For more information, visit Sonim Accessories.


About Sonim
Sonim Technologies is a leading U.S. provider of ultra-rugged mobility solutions designed specifically for task workers physically engaged in their work environments, often in mission-critical roles. The Sonim solution includes ultra-rugged mobile phones, a suite of industrial-grade accessories, and data and workflow applications which are collectively designed to increase worker productivity, communication and safety on the job site. Please visit

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