Cordless telephone apparatus having a low power stand-by mode and a hold mode

Claim 1

A cordless telephone apparatus comprising: a base unit connected to a telephone line network for connection through the latter with a desired party; a handset unit operable upon opening of a communication channel selected from among a plurality of communication channels for radio communication of informational and mode control signals with said base unit so as to enable communication of said informational signals through the telephone line network with said desired party and having means for establishing an initiating and terminating mode in which said radio communication between said base unit and said handset unit is respectively initiated and terminated; means for establishing a low power standby mode in which said handset unit intermittently monitors at least one predetermined communication channel from among said plurality of communication channels and said base unit monitors all of said plurality of communication channels; means automatically responsive to an interruption of said radio communication between said handset and said base unit for establishing a channel changing mode in which said communication channel opened between said base unit and said handset unit is changed to another of said communication channels; means for establishing and releasing a hold mode in which the communication of said informational signals between said handset unit and said desired party is inhibited when said hold mode is established; and means for continuously monitoring said communication channel opened between said base unit and said handset unit for a predetermined period after initiation of said hold mode so as to detect one of said mode control signals indicating termination of said radio communication, releasing of said hold mode and establishing of said channel changing mode for changing of said communication channel opened between said base unit and said handset unit, respectively, and, in the absence of detection of any of said mode control signals, for placing said handset unit in said stand-by mode after said predetermined period.