Cordless telephone

A cordless telephone system, comprising:

• a. a base unit for connection to telephone lines, said unit including
• means for transmitting and receiving signals to and from a cordless telephone,
• means for passing said received signals that are within a given audio frequency band onto the telephone lines,
• means for detecting a discrete control signal received from the cordless telephone and for enabling the base unit to seize the telephone lines in response thereto;
• and
• b. a cordless telephone, including
• means for transmitting and receiving signals to and from the base unit, and
• means for generating said discrete control signal for transmission to the base unit;
• Characterized by
• the discrete signal generating means and the detecting means being adapted for respectively generating and detecting a said discrete control signal having a low frequency within a frequency range below said given audio frequency band;
• and
• the cordless telephone transmitting means comprising means for preventing intermodulation of said discrete control signal and transmitted signals within said given audio frequency band.

A cordless telephone for use in a telephone system with a base unit that is connected to telephone lines for transmitting and receiving telephone switching signals and audio signals between the telephone lines and the cordless telephone, the cordless telephone comprising:

• a speaker and a microphone;
• and
• means for transmitting and receiving telephone switching signals and audio signals to and from the base unit,
• first control means for enabling and inhibiting energization of the cordless telephone to enable and inhibit the cordless telephone to receive and detect a "ring" signal from the base unit and to provide said ring signal to the speaker;
• and
• second control means for enabling and inhibiting the transmitting means in the cordless telephone, and for enabling and inhibiting the receiving means in the cordless telephone to provide audio signals from the base unit to the speaker;
• Characterized by
• the cordless telephone comprising a touch-tone signal generator module for generating switching signals, said module including ten buttons for initiating the generation of signals representing ten numeric characters, and two additional buttons,
• wherein one of the two additional buttons is adapted for operating the first control means, and
• the second additional button is adapted for operating the second control means.

A cordless telephone for use in a telephone system with a base unit that is connected to telephone lines for transmitting and receiving signals that are within a given audio frequency band between the telephone lines and the cordless telephone, said base unit including means for detecting a discrete control signal received from the cordless telephone and for enabling the base unit to seize the telephone lines in response thereto;

• the cordless telephone comprising:
• means for transmitting and receiving signals to and from the base unit, and
• means for generating said discrete control signal for transmission to the base unit;
• Characterized by
• the discrete signal generating means being adapted for generating said discrete control signal having a low frequency within a frequency range below said given audio frequency band;
• and
• the cordless telephone transmitting means comprising means for preventing intermodulation of said discrete control signal and transmitted signals within said given audio frequency band.