A base module for a switch-cabinet system, having a plurality of communication units and connection elements for a plurality of functional modules. The connection elements are configured to engage in module-connection elements of functional modules. Each connection element has at least one data connection. Each communication unit is in each case connected to at least one data connection of a connection element. The communication units are connected to one another by a data bus. The base module has a first field-bus connection. The data bus is connected to the first field-bus connection to connect the communication units to a field-bus.