The first step to really understanding OT is to forget everything you know about IT. IT has learned a lot of lessons over the past 20+ years, and starting from scratch means relearning those lessons in a painful way. The desire for convenience and efficiency is eroding the traditional air gap between OT and IT, sometimes to the point where there is no gap at all. Attackers can get at OT devices from IT (Target), or IT systems from OT (Ukrainian power grid)”]
Source: https://www.csoonline.com/article/3115584/a-tale-of-two-t-s.html