It's built for larger, more complex digital switching installations where a single central controller needs to coordinate multiple Connect modules, sensors and switched circuits across a vessel, rather than a simple single-module setup. The GSM variant adds cellular connectivity to the control unit, enabling remote monitoring, alerts or control of the boat's digital switching system over a mobile network connection - useful for checking a boat's status (bilge pumps, battery state, security sensors) while away from the vessel, rather than only being able to see the system's state from the helm display itself. This is a specialist marine integrator/installer component, sold as part of building out or expanding a full EmpirBus digital switching system rather than a standalone consumer accessory.