Sony Corporation

Kazunori Nakajima

Takashi Enomoto

Masato Yamagata

Hiroshi Miyamoto

Toshiharu Tajiri

Tsutomu Iwaoka

Hidekazu Sato

In a cordless telephone having no control channel, the time required for connecting a cordless handset to a base unit is reduced in a cordless telephone wherein a cordless handset and a base unit are connected using any one of a plurality of communication channels to allow a call, the plurality of communication channels are divided into a plurality of groups. By using a communication channel included in one of the plurality of groups, standby, calling, and call receiving modes of operation are effected.

Cordless telephone with division of channels into groups of channels

In a cordless telephone set, a base unit which itself has no loudspeaker function is made to provide a loudspeaker function at low cost. The base unit 2 has a transmitting circuit 22 for transmitting an aural signal and data to the handset 1 and a receiving circuit 23 for receiving and extracting the aural signal and data transmitted from the handset 1. A line interface circuit 25 coupled to a telephone line 3, a loudspeaker 44, and a selector circuit 28 for switching connection of the aural signal line between the transmitting circuit 22, the receiving circuit 23, the interface circuit 25, and the loudspeaker 44 are provided. In normal use, the transmitting circuit 22 and the receiving circuit 23 of the base unit 2 are connected with the line interface circuit 25 via the selector circuit 28. When predetermined push buttons 17 on the handset 1 are operated, the base unit 2 controls the selector circuit 28 so that the telephone line 3 is connected to the loudspeaker 44 via the selector circuit 28.

Cordless telephone system having base unit with speaker

Growing community of inventors

Saitama, Japan

Kazunori Nakajima