Headset for hands-free wireless telephone

Abstract

A wireless telephone using an RF receiver unit and an RF transmitter unit and having a removable headset, the telephone and headset particularly suitable for applications where the RF transmitter unit is switched on and off at a frequency less than twenty kilohertz. The wireless telephone is coupled to the headset using a conventional stereo plug and jack. A headset detect logic signal is generated from the speaker audio line. A microphone current detect logic signal is generated from the microphone audio line. A digital logic circuit, preferably including a microprocessor, monitors the headset detect logic signal and microphone current detect logic signals and generates a programmed response to the headset detect logic signal. The programmed response reduces audible noise to the headset user, generates a ringing signal on the speaker audio line when an incoming call is received and allows the headset user to answer incoming calls, and place outgoing calls while touching only the headset. The wireless telephone and headset include circuitry to reject RF noise and circuitry to attenuate RF noise passed into the wireless telephone by a long multi-conductor wire coupling the headset to the wireless telephone.