Electro-mechanical switching system

Claim 1

An electro-mechanical selection system, comprising: a rotary switch having an integer number N of movable terminals electrically coupled with one another and N discrete angular positions and first, second and third stationary terminals, the movable and stationary terminals being positioned and spaced so that by rotating the switch clockwise from one discrete angular position to the next discrete angular position, a movable terminal makes electrical contact with the first stationary terminal then another movable terminal makes electrical contact with the third stationary terminal before any movable terminal makes electrical contact with the second stationary terminal; and by rotating the switch counterclockwise, a movable terminal makes electrical contact with the third stationary terminal then a different movable terminal makes electrical contact with the first stationary terminal before any movable terminal makes electrical contact with the second stationary terminal; means for coupling a signal to all of the movable terminals; a memory element coupled to the first and third stationary terminals for memorizing which of the first or third stationary terminals was contacted last before the second stationary terminal was contacted by a movable terminal; and an up/down counter having an up/down input for controlling whether the counter counts up or down coupled to an output of the memory element and a clock input coupled to the second stationary contact for receiving a clock signal from the second stationary contact after an up/down selection thereof was determined by the memory element, whereby the counter counts in one direction (up or down) when the switch is rotated clockwise and counts in the other direction (down or up) when the switch is rotated counter-clockwise.