Patent ID: 6700975
Filing Date: 2004-03-02
Classification: H04M

Abstract:
A subscriber line interface circuit, comprising:means adapted to apply to a line, associated with the line interface circuit, a substantially constant line current, IL1 for line voltages up to a first voltage, UL1, wherein the absolute value of UL1 is lower than a supply voltage, VBAT, by a fixed amount; means adapted to apply to the line, a line current which is inversely proportional to the line voltage and a value between IL1 and a second current IL2 for line voltages between the first voltage, UL1, and a second voltage, UL2, wherein the absolute value of UL2 is higher than UL1 by a fixed amount; and means adapted to maintain the line voltage substantially constant for line currents less than IL2, such that the line interface circuit is self-adjusting with respect to supply voltage variations.