Patent ID: 6483914
Filing Date: 2002-11-19
Classification: H04M

Abstract:
A filter arrangement for coupling a telephone set to a subscriber loop carrying both voice and data traffic so as to remove unwanted voice band frequencies when the telephone set is in its of-hook condition and to inhibit interference with similar sets connected in parallel with the telephone set when the telephone set is in its on-hook condition, the filter arrangement comprising: an inductor coupled in series with the telephone set; a capacitor coupled in parallel with the telephone set; and switch means coupled in series with the inductor, wherein said switch means is constituted by a semiconductor bi-state switch having a first high impedance state and a second low impedance state achieved by application of a threshold voltage to the device and passage of a threshold current therethrough, said bi-state switch being responsive to the telephone line voltage and line current so as to present a low impedance to the line when the telephone set is in its off-hook condition and a high impedance to the line when the telephone set is in its on-hook condition.