Abstract: A mobile unit is normally disposed in a predetermined positional relationship with a base unit connected to a wired line. For example, the mobile unit is mounted on the mobile-unit receiving part of the base unit. If the predetermined positional relationship is changed, it is detected by means of a detector such as a electrical, mechanical, or optical detector. In response to the detection of a change in the predetermined positional relationship, a radio link may be established between the base unit and the mobile unit or a communication link may be established between the mobile unit and a calling party. Furthermore, in response to the detection of the change, the mobile unit or the base unit may be partly or entirely powered so as to establish the radio link or the communication link. When the mobile unit is reset to a position in the predetermined positional relationship, it is detected by the detector.

Abstract: A radio telephone apparatus comprising a main station connected to a wire telephone line and having a subsidiary telephone set, and a radio telephone set connected with the main station via a radio link, wherein the radio telephone set effectively or ineffectively controls a function of releasing the hold state by the off-hook operation of the subsidiary telephone set. By the operation of the radio telephone set, telephone communication can be switched between a self-hold state and a complete hold state. The self-hold state can be released only by the radio telephone set while the complete state hold can be released by any one of the radio telephone set and the subsidiary telephone set. In the complete hold state, the radio link between the main station and the radio telephone set is disconnected. If the complete hold state is released by the radio telephone set, the radio link is again established between the main station and the radio telephone set.