A radio module RM for field devices of automation technology is connectable with a field device, e.g. F1, via a field device interface. The radio module RM includes a microcontroller μC for function control, a radio unit RF for data communication with a superordinated unit, and an energy supply unit ESU. With the help of the radio module RM, conventional field devices can be adapted simply to become radio-capable field devices, in order that they can then also be used in radio networks.