Abstract: A module interfaces a programmable controller to several serial communication networks over which data may be exchanged according to different protocols. A module has a central controller and a separate port circuit for each of the networks. Each port circuit includes a microprocessor and a shared memory to which both the central controller and the port microprocessor have access for the exchange of data. The central controller transfers data from the shared memories to a module output coupled to other components of the programmable controller. A removable memory cartridge stores a plurality of programs for execution by the port microprocessors to exchange data over the networks using different communication protocols. Configuration data is stored in the module defining which program is to be transferred from the memory cartridge into the shared memory of each port circuit.