ICS, short for Industrial Control Systems, can be a part of the electrical and water supplies among others, which are important instances for society. This all resides in the realm of Operational technology, abbreviation OT. Due to technological development, Information Technology i.e. IT is introduced and merged into the realm of industrial systems, because of society’s increasing dependencies on digital infrastructures and services.ICS and Supervisory Control and Data Acquisition (SCADA) systems are rather well known and reputable. In the realm of OT, there’s a range of different systems, and ICS itself encompasses a range of process automation technologies, such as SCADA systems and Distributed Control Systems (DCS) among others.This paper aims to try to define and differentiate a distinct boundary of systems without any connection to IT and can be considered purely OT, if they exist at all. This by conducting an interview with people working for governmental agencies with an eminent amount of experience in the realm of OT. What kind of systems are currently in operation today that don’t fit into the realm of ICS, do they exist at all and how do they work?The definition and differentiation of OT may indicate a subset of systems and components, and terminologies of systems in the OT-realm are misused, indicating a lack of insight in this realm of industrial systems.