6638514A1 is the ABB Bailey OIS External Membrane Keyboard Assembly, Rev A10, a membrane-style operator keyboard used as the primary human–machine interface for Bailey Infi90 and Net90 distributed control systems. Hardware references describe it as a keyboard assembly (mylar) for the OIS front end, providing external membrane input for operator interaction within Bailey OIS configurations. This part is designed for legacy Bailey Infi90 deployments, enabling reliable keypad input as part of the OIS operator station.
