US Patent 7432782 Signal splitter

A signal splitter includes a low-pass filter circuit for permitting a low-frequency component of an incoming signal in an incoming telephone line coupled to a first connecting port to pass therethrough to a second connecting port, and a coupling circuit including a capacitor coupled between a first terminal of the first connecting port and a second terminal of the second connecting port, and a coupling transformer having a primary winding that interconnects the first terminal of the first connecting port and a first input end of the low-pass filter circuit, and a secondary winding that interconnects the second terminal of the second connecting port and a second output end of the low-pass filter circuit.