Patent ID: 6263076
Filing Date: 2001-07-17
Classification: H04M

Abstract:
An arrangement for determining a line resistance of a line comprising a tip wire and a ring wire connected to a line interface circuit to which a control processor is connected, the control processor being adapted to control the line interface circuit and monitor a status of a line via a detector output terminal of the line interface circuit to determine the line resistance,the control processor is further adapted at a first point of time to control the line interface circuit to ensure that the detector output terminal is in a first signal state and to initiate charging of a capacitor normally charged to a voltage corresponding to the voltage of the ring wire.the line interface circuit is adapted to bring the detector output terminal to a second signal state when the capacitor has been charged to a voltage corresponding to the voltage of the tip wire and the capacitor is connected to the tip wire when the voltage of the capacitor corresponds to the voltage of the tip wire, andthe control processor is further adapted to measure the time interval between the first point of time and the time when the detector output terminal is brought to the second signal state, convert the measured time interval to a voltage value corresponding to the line voltage, calculate the line resistance from that voltage value, and, in response to the calculated line resistance, control the line interface circuit to compensate for line resistance dependent attenuation on the line.