In a communications network, a method and apparatus are disclosed for using a graphical user interface for telephony call control. In an aspect, a user equipment determines whether to send a packet based on available transmit power. A single bearing is located between both rotors along the axis of rotation. As another aspect of the X-rays CT apparatus, there is provided an operation unit configured to operate a position of the X-ray radiation source. , position, orientation, and shape, using a control system. The characteristics of nonlinear compensation are changed according to the brightness of a place in which the display device is installed.