Abstract: A drive mechanism for positioning a moveable indicator in rotation about, and/or radial displacement with respect to, a fixed reference index. Dual dial cord drives are employed which are driven from respective inputs definitive of the rotation and radial displacement to be individually or compositely imparted to the moveable indicator. The pair of dial cords are attached circumferentially to diametrically opposed portions of a cylinder with the moveable indicator extending on a diameter common to those portions. The cylinder portions are confined between, and maintained in sliding tangential engagement with, respective ones of a pair of space-separated, fixed-mounted channel guides. Implementations of the cylinder portions are exampled as diametrically opposed segments of a cylinder, diametrically opposed points on a ring, and diametrically opposed circumferential extremes of a cylindrical plate.