Patent ID: 7171167

Claim:
An apparatus for routing a mobile phone incoming call to a connected land-line telephone, the apparatus comprising: an interface to connect with a headphone outlet of the mobile phone to receive ringer and voice AC signals from said mobile phone as input; an RJ11 port arranged to be interfaced with a first cable, said first cable being arranged to be coupled to said land-line telephone in order to send a DC voltage sufficient to drive a ringer of said land-line telephone and to output an AC voltage for voice conversation; an approximately 110V AC power plug arranged to be connected to an approximately 110V AC power supply that is arranged to provide sufficient power to operate said apparatus; a power supply circuit to convert an approximately 110V AC power to an approximately 11V DC power; a voltage driver circuit arranged to split the approximately 11V DC power into an approximately 8V DC power and an approximately 11V DC power; a ring tone generator (RTG) arranged to be interfaced to the headphone outlet of the connected mobile phone which, upon receiving an incoming call, outputs an approximately 3V AC signal, the approximately 3V AC signal being arranged to generate a series of high-low voltage cycles to drive the ringer of said land-line telephone; and an impedance variation detector (IVD) arranged to, upon detecting a line resistance variation caused by lifting or hanging-up telephone handset from a hook of said land-line telephone, switch the approximately 11V DC power to said RTG to silence the ringer of said land-line telephone or to prepare for the approximately 3V AC signal that is arranged to drive the ringer of said land-line telephone, wherein said IVD comprises: a high pass filter circuit that is configured to attenuate substantially low frequency signal in a human voice range, the high pass filter including at least one resistor, at least one induction coil, and at least one capacitor; a capacitor arrangement arranged to remove high frequency background noise; a diode arrangement arranged to regulate a current direction and to compensate for a parasitic AC voltage; and a differential amplifier arranged to drive a mechanical relay unit.