Subsea Modem (SuM) – The World’s First Low-Cost, Software-Defined Underwater Acoustic Modem is Made in Italy
SubSeaPulse SRL introduces SuM: the world’s first low-cost, software-defined underwater acoustic modem. Engineered for both research and industrial applications, SuM delivers unparalleled versatility. Deploy it as a low-power acoustic modem powered by our robust modulation and coding scheme, or use it as an analog front-end to test custom acoustic signals in full compliance with the JANUS NATO standard.

Affordable software-defined architecture
SuM is an affordable, software-defined acoustic modem featuring a three-layer architecture: a Raspberry Pi, a high-quality sound card, and a custom frontend. The integrated Raspberry Pi acts as the primary computing platform, eliminating the need for extra embedded computers while greatly simplifying underwater experimentation.
Fully open and extensible
Designed as a completely open platform, SuM allows users to develop, install, and execute custom signal-processing algorithms directly on the device. It features a rolling-release software model, enabling continuous evolution with updates that add new modulation schemes, networking capabilities, and analog voice communication.
Seamless Networking & ROS Support
SuM natively supports underwater multihop and multipath networking by integrating seamlessly with the open-source DESERT Underwater framework. Dedicated interfaces for the Robot Operating System (ROS) further enable coordinated operations among autonomous underwater vehicles, fostering research in swarm robotics and distributed autonomy.
Broad Transducer Compatibility
The modem offers exceptional flexibility, working with everything from ultra-low-cost custom DIY transducers to professional-grade hardware used in offshore and defense applications. By matching the amplifier impedance to professional transducers, SuM has achieved communication ranges extending beyond 3 km in seawater.
Advanced Localization Capabilities
Alongside data transmission, SuM provides underwater localization by measuring the Round-Trip Time (RTT) between mobile and fixed anchor nodes. By equipping the modem with an optional high-precision clock, users can achieve higher positioning update rates using One-Way Travel Time (OWTT) measurements.
Configurable Frequency & Power Management
The system features a software-configurable operating frequency range from 2 Hz to 70 kHz to suit various underwater environments. Users can also tailor power and processing capabilities by choosing a Raspberry Pi 4 for intensive digital signal processing or a Raspberry Pi Zero for deployments with strict energy constraints.



Looking for a more powerful solution?
The Subsea Software-Defined Acoustic Modem v2: Extended Capabilities and Sea Test
Published Papers
Experimenting Various JANUS Frequency Bands with the Subsea Software-Defined Acoustic Modem
A New Wave of Underwater Comms Is Coming Low-cost acoustic modem is built on a Raspberry Pi