A network includes a power over data link, a data switch coupled to a data bus and configured to transmit and/or receive data from and/or to the data bus via the power over data link, and a service device coupled to the data switch via the power over data link and configured to transmit and/or receive data from and/or to the data switch via the power over data link. The service device has a power splitter to split the data signal of the power over data link from the power supply, service functions coupled to the power splitter and configured to receive power from the power splitter, and a voltage comparator coupled to the power splitter. The voltage comparator is configured to detect voltage level of the power supply, and based on the detected voltage level, to selectively activate and/or deactivate one or more of the service functions.