Firedamp is encountered in underground coal mining, in particular. The air enriched with the mine gas methane and coal dust can lead to extremely violent explosions if ignited. That is why the methane content of the atmosphere in mines is monitored constantly. Mobile communication devices are practical tools for organizing countermeasures if the monitoring system reports a limit value violation. To ensure the means of communication does not become a source of ignition in this case, it must meet clearly specified requirements. Our category M1 devices are characterized by a very high level of safety.