The Simatic Microbox PC 420, the industrial PC composed of the rugged Embedded series of units from Siemens Automation and Drives (A&D), can now be flexibly expanded with modules for central I/O (input/output) tasks. A maximum of 120 analog I/Os, 320 digital I/Os and 12 encoder/counter interfaces can be added in the form of new digital and analog I/O modules as well as encoders/counters integrated by means of the PC/104 modules.