RTU
Remote Terminal Unit
Fernbedienungsstation
An RTU is a robust field station that captures measurements and executes commands from a control centre at remote or inaccessible locations — such as at a pipeline, a substation or a water station. It is the interface between the central Supervisory Control and Data Acquisition (SCADA) system and the distributed facility on site. It often works autonomously and over long distances.
History & facts. RTUs are designed to function reliably under harsh conditions and over long distances; they communicate with the control centre frequently via telecontrol protocols such as IEC 60870-5-104. Like other Operational Technology (OT) components they arose at a time when physical remoteness and closed networks were considered protection — an assumption that no longer holds with increasing networking.
Outlook & recommendation. Because RTUs are distributed and partly hard to secure physically, securing their communication paths and remote access is of particular importance. Protection means: segmentation, controlled and monitored remote access and the observation of telecontrol communication for anomalous commands. RTUs are a typical example of distributed Operational Technology (OT) assets whose monitoring must start precisely where no classic endpoint agent runs.