A control device, controlling an alarm output, includes a data network interface, with a signaling interface for outputting a control signal indicating a request for an acoustic and/or optical alarm signal a memory unit and a processor. The data network interface is configured to receive a group message indicating a sender identity and a presence of an alarm state. The memory unit provides a first data set, which indicates a list with potential sender identities, as well as further a second data set, which indicates one or more alarm output time periods. The processor is configured to operate a timekeeping function, and to output the control signal via the signaling interface as a function of an agreement between the sender identity with one of potential sender identities, and as a function of a comparison of a current value of the timekeeping function with data of the second data set.