Otis 211 (possibly also called Otis Elevonic 211, unless that is a different model) is an Otis hydraulic elevator controller. It was first made in 1987. This controller was discontinued in 2013. The Otis HydroFit model elevator uses a different controller now, which does not have an official name.
This is a solid state elevator controller. It is unknown if the version of Series 1 fixtures can be used to tell if the elevator has a 211 controller or not. Otis also made the 211M, for modernizations, and the 211LVM (1987-2013).