Stereo interface telephone ring detector

Claim 1

A method of audibly alerting a headphone listener to an incoming telephone call comprising the steps of: forming an electrically connected interface directly between a headphone set, a telephone line and an amplifier; electrically detecting directly upon said telephone line the presence of an increased voltage signal generated by said incoming telephone call; generating a tone signal in response to the detection of said incoming telephone call; applying said tone signal to said headphone set; and automatically momentarily interrupting the normal signal from said amplifier applied to said headphone set when said tone signal is applied to said headphone set, said detecting step further comprising the step of rectifying said increased voltage signal generated by said incoming telephone call, said generating step further comprising the steps of applying said rectified voltage signal to an oscillator and modulating the output from said oscillator to produce a modulated tone signal, and said automatic interrupting step comprising the further steps of applying said rectified voltage signal to drive a switching transistor; and switching a relay in response to said driving of said switching transistor to selectively connect said modulated tone signal to said headphone set.

Claim 2

A method of audibly alerting a headphone listener to an incoming telephone call comprising the steps of: forming an electrically connected interface directly between a headphone set, a telephone line and an amplifier; electrically detecting directly upon said telephone line the presence of an increased voltage signal generated by said incoming telephone call; generating a tone signal in response to the detection of said incoming telephone call; applying said tone signal to said headphone set; and automatically momentarily interrupting the normal signal from said amplifier applied to said headphone set when said tone signal is applied to said headphone set, said detecting step further comprising the step of rectifying said increased voltage signal generated by said incoming telephone call, said generating step further comprising the steps of applying said rectified voltage signal to an oscillator and modulating the output from said oscillator to produce a modulated tone signal, and said automatic interrupting step comprising the further steps of applying said rectified voltage signal to drive a switching transistor; and switching a relay in response to said driving of said switching transistor to selectively connect said modulated tone signal to said headphone set.