Abstract: A method and apparatus for enabling a user to remotely select which communications device to use for a particular communications session from among a plurality of communication devices connected to standard residential telephone wiring. The user enters a predetermined signal from any of the devices connected to the residential wiring. The method of the present invention analyzes the signal and, depending on the state of a number of variables related to cost effective operation, selects which of the devices is the most economical for a particular communications session.

Abstract: A method and apparatus for enabling a user to remotely select which communications device to use for a particular communications session from among a plurality of communication devices connected to standard residential telephone wiring. The user enters a predetermined signal from any of the devices connected to the residential wiring. The method of the present invention analyzes the signal and, depending on the state of a number of variables related to cost effective operation, selects which of the devices is the most economical for a particular communications session.

Abstract: A cordless telephone includes a ring detector state machine module to facilitate the answering of a call received at the cordless telephone. A screening state machine module enables three-way connection and aural monitoring of the incoming call on the cordless telephone.

Abstract: A security system for cordless telephones prevents unauthorized telephone lls over telephone lines. The system includes a base unit and a cordless handset unit which must share common information for proper operation. To prevent an unauthorized user in possession of a handset unit from easily matching a security code stored in the base unit and thereby obtain dial tone therefrom, the security code in the base unit is transferred to the handset unit while the handset unit is in a mating cradle in the base unit. Transfer circuits in the base unit and the handset unit respectively transmit and receive the security code and also an operating frequency channel over a direct-current charging path provided for charging of a battery in the handset unit whenever the handset unit is returned to the cradle.

Abstract: A hands-free telephone system is disclosed utilizing an infrared transmitter and receiver to permit wireless speech transmission. The transmitter uses frequency modulation imposed on the infrared signal and includes carrier shift signaling arrangements for indicating a low battery condition and transmitter turnoff. The receiver utilizes a noise detection circuit for permitting remote turn-on, for squelching noise in the voice path, and for feeding an alerting signal to a loudspeaker to indicate that the received signal is excessively noisy. The portable transmitter must then be moved or redirected to provide a better line-of-sight signaling path.