Abstract: A multiple position switch includes a housing containing a plurality of membrane switches located in a predetermined pattern. A spring-based, normally centered actuator is mounted in the housing for selective movement to actuate one of the switches. A finder plate is attached to the housing and has a notched circular opening in alignment with the plurality of switches. The actuator is guided to a selective switch location by its engagement with one of the finder plate notches when the actuator is moved in close proximity to a selective switch location.

Abstract: A polarization key is disclosed for installation in an electrical connector on a backplane circuit board. The key has a tongue portion for insertion into the connector, engaging the resiliently biased contacts of the connector. A tab portion of the key projects outwardly from the connector to prevent the insertion of another circuit board therein unless the other circuit board is properly slotted to mate with the key. A pair of legs extend from the tab portion of the key along the outside of the connector to enter holes provided in the backplane circuit board.