Abstract: An improvement in a data link, such as is used for continuously transferring data concerning operations of textile yarn forming machines such as ring spinning frames, wherein a transmitter and receiver each use particular combinations of oscillators and phase locked loop circuits to function as frequency synthesizers.

Abstract: An improved sensor arrangement for use in an apparatus which travels a detector along ttextilestrand processing machines such as spinning frames for determining the absence of ends of yarn from locations therealong at which such ends normally are present and for thereby locating ends down on the textile strand processing machines. The arrangement disclosed herein includes an optical system defining a light path for focusing light reflected from yarns and a plurality of sensors for receiving light passed along a common light path by the optical system and for generating pulse electrical signals in response to variations in illumination in respective, vertically spaced and aligned, fields of view.