First apparatuses (10) such as tags and batches comprise receivers (11) for receiving ultrasonic signals (1) comprising first codes from sources (27, 30), analyzers (12) for analyzing first codes, transmitters (13) for transmitting electromagnetic signals (2) comprising second codes to second apparatuses (20), and controllers (14) for, in response to analyses of first codes, controlling at least parts of the first apparatuses (10), such as modes, transmissions, and supplies of second codes. Second apparatuses (20) such as parts of interfaces and parts of stations comprise receivers (21) for receiving the electromagnetic signals (2) comprising second codes from the first apparatuses (10), analyzers (22) for analyzing second codes, and generators (23) for, in response to analyses of second codes, generating parameter signals (5) defining issues like registration issues and authorization issues and environmental issues, and analysis results. The first apparatuses (10) may form part of first devices (100) such as mobile phones and organizers, and the second apparatuses (20) may form part of second devices (200) such as interfaces and stations.