The central unit is a web-based program that evaluates the data transmitted by the control sections, generates the commands for the display sections and documents the display states. The central unit must be kept in a data centre (OC) that is permanently staffed (365 days a year, 24 hours per day) and provides monitoring and support in compliance with the EU standard contractual clauses. The data centre must agree to be a contractual data processor and comply with the corresponding regulations.