A field device, in particular a field device of a room automation system or of a power management system or of a hazard detection system, comprising: at least one human-machine interface with at least one memory configured to store physical layer data, at least two protocol stacks (3a, 3b, 3c) configured to communicate with another device, wherein the field device provides a controller configured to select at least one protocol stack (3a, 3b, 3c) based on the physical layer data stored in the memory of the human-machine interface, wherein the field device further comprises at least two physical layer elements (6a, 6b, 6c), and at least two compatible pairs, wherein each compatible pair comprises at least one physical layer element (6a, 6b, 6c) of the field device and at least one protocol stack (3a, 3b, 3c) of the field device, wherein the field device further comprises at least one selector switch configured to connect and to disconnect physical layer elements (6a, 6b, 6c) and protocol stacks (3a, 3b, 3c), such that a physical layer element (6a, 6b, 6c) and a protocol stack (3a, 3b, 3c) connected or disconnected by the at least one selector switch belong to the same compatible pair, characterized in that the selector switch is configured to connect multiple compatible pairs at a time, such that all compatible pairs other than the compatible pairs connected by the selector switch are disconnected and in that the field device comprises a number n of compatible pairs and wherein n is larger than one and wherein the selector switch is configured to connect a number m of multiple compatible pairs at a time and wherein m is larger than one and less than or equal to n, such that n over m configurations exist and / or are attainable. at least one human-machine interface with at least one memory configured to store physical layer data, at least two protocol stacks (3a, 3b, 3c) configured to communicate with another device, wherein the field device provides a controller configured to select at least one protocol stack (3a, 3b, 3c) based on the physical layer data stored in the memory of the human-machine interface, wherein the field device further comprises at least two physical layer elements (6a, 6b, 6c), and at least two compatible pairs, wherein each compatible pair comprises at least one physical layer element (6a, 6b, 6c) of the field device and at least one protocol stack (3a, 3b, 3c) of the field device, wherein the field device further comprises at least one selector switch configured to connect and to disconnect physical layer elements (6a, 6b, 6c) and protocol stacks (3a, 3b, 3c), such that a physical layer element (6a, 6b, 6c) and a protocol stack (3a, 3b, 3c) connected or disconnected by the at least one selector switch belong to the same compatible pair, characterized in that the selector switch is configured to connect multiple compatible pairs at a time, such that all compatible pairs other than the compatible pairs connected by the selector switch are disconnected and in that the field device comprises a number n of compatible pairs and wherein n is larger than one and wherein the selector switch is configured to connect a number m of multiple compatible pairs at a time and wherein m is larger than one and less than or equal to n, such that n over m configurations exist and / or are attainable. the field device comprises a number n of compatible pairs and wherein n is larger than one and wherein the selector switch is configured to connect a number m of multiple compatible pairs at a time and wherein m is larger than one and less than or equal to n, such that n over m configurations exist and / or are attainable.