Abstract: A plurality of rings each having gear teeth in the outer periphery thereof and rotatably mounted for individual rotation, each ring having associated therewith a fixed electrical contact and a wiper contact for engaging a plurality of fixed contacts as the ring rotates. A drive gear associated with each of said rings and driven from a single control, said drive gears being mounted so that only one gear is engaged with its associated ring at any one time and the drive gear to be engaged is selected by means of a ratchet and pawl that operates from a single locking control and rotates a wheel having escarpments thereon for moving the drive gears axially into engagement with the rings.