A system on module (SoM) is a circuit board that integrates a system function on a single module/device. Unlike a single board computer like the Raspberry Pi or a microcontroller, a SoM generally serves a single special function.
The Blues Wireless Notecard is a cellular SoM. The Notecard is a secure device-to-cloud data-pump that comes with 500 MB of data and 10 years of cellular service. The Notecard itself is a tiny 30mm x 35mm SoM and ships ready to embed in a project via its m.2 connector. To make prototyping IoT solutions even easier, Blues Wireless also provides a series of expansion boards to host the Notecard called Notecarriers.