Acronym of Remote Terminal Unit.

Remote Terminal Unit (RTU) is an industrial data collection and control device typically located at a remote location and communicates with a host system by using telemetry (such as radio, dial-up telephone, or leased lines).

RTUs are often used in applications where control/monitoring is required over a very large geographic areas and communication channels are often disconnected due to poor reliability, expense, or availability issues. These include remote oil wells, transmission and distribution systems, mining, etc.

RTUs are different from PLCs in that their operation assumes that communication with the host system is typically (or often) disconnected. In addition, an RTU frequently includes communication hardware whereas a PLC does not.

Many RTUs have an OPC Server to enable external applications to collect their data using a standards-based system.

See also: PLC, SCADA