Abstract: A cordless telephone is composed of a base unit connected to a telephone line and a handset unit capable of radio communications with the base unit. When the handset unit or the base unit initially transmits radio waves for forming a radio link, a channel is selected from a group of channels through which transmission is permitted irrespective of their electric field states, and the radio waves are transmitted through the selected channel. After the radio link has been formed, a speech channel is selected from all channels through which transmission is permitted. In this way, when the base unit or the handset unit initially transmits control data, the transmission is immediately carried out irrespective of an electric field state on the selected channel, whereby the radio link can be established in a reduced time. Further, when a speech communication is started, 15 channels additionally provided by the revised standard can be effectively utilized.

Abstract: In a cordless telephone apparatus, a mobile set is provided with a remaining a battery amount measuring section which is incremented or decremented in accordance with a value corresponding to an operating condition of the mobile set and a value corresponding to a charging current set by a charging current change=over circuit. A full charge condition is detected on the basis of a value measured by the remaining battery amount measuring section, and this is used to control the charging current. Thereby, it becomes possible to operate the mobile set from the battery even in the course of charging, and to control the charging time and the charging current considering the electric power used for the operation of the mobile set. Since the charging time and the charging current are accurately adjusted in accordance with use conditions of the mobile set, it becomes possible to prevent over-charging and under-charging.

Abstract: A cordless telephone system comprises a base station, a handset unit, and a speaker phone circuit provided in the base station. In response to a request signal indicating that the handset unit uses the speaker phone circuit of the base station, the base station controls its communication path switching means (SW 33, 34) to connect its own speaker phone circuit (28) to a radio transmitting section (20) and a radio receiving section (18). Audio signals picked up by a microphone of the handset unit are transmitted to the speaker phone circuit (28), while audio signals of the speaker phone (28) are sent to a speaker of the handset unit. With this arrangement, a speaker phone communication is realized by the handset unit even if the handset unit has no speaker phone circuit.