Abstract: A rotating data transmission device has a rotating part, such as a rotor, and a stationary part, such as a stator. One of the parts is in the form of a waveguide coupled to a set of transmitters. The other part has a set of receivers associated therewith, the number of transmitters being different from the number of receivers. The transmitters and receivers are respectively located at positions which guarantee continuous data transmission with no interruptions during relative movement of the parts. This results during transmission in certain waveguide sections which are not always required for primary data transmission, thus making those sections available for use as secondary transmission paths. The device is particularly suited for use in a computer tomograph apparatus for transmission of measured data and control data at a high rate.