A measurement or protective device has an interface for establishing a connection to at least one measurement transducer and a further interface for connecting to a superordinate data bus. In order to allow the measurement or protective device to be used in a particularly universal manner and to make it possible for complex protective systems to be constructed in a particularly cost-effective manner, a communication unit is provided in the measurement or protective device. The communication unit is connected to both interfaces, can be directly connected to the measurement transducer via the interface, can be connected to the superordinate data bus via the further interface, forms messages and transmits them to the superordinate data bus.