IMS International was a US computer manufacturer. The initialism “IMS” stood for “Industrial Micro Systems”. Little is known about the organisation, but some details are on Herb Johnson’s Industrial Micro Systems/IMS International page.
Only one IMS keyboard model is presently known: the keyboard from the 5000 IS “desktop mainframe” system. The sole example is or was in MouseFan’s possession. This keyboard a moving-ferrite ferrite core implementation, marked as though it were manufactured by IMS in-house in the US. There is no model label on the keyboard, and presently no suggestion that it was patented. The copyright date on the PCB is 1982, while the encoder or controller chip is dated week 13 1983.
The relationship if any between IMS and ADI ferrite core keyboards is not known. The general design is the same, but there are noticeable differences, including ADI doubling-up on winding tracks.