TERMINAL DEVICE FOR DIAGNOSING FAILURE OF TRANSMISSION LINE AND METHOD OF DIAGNOSING FAILURE OF TRANSMISSION LINE AND MEASURING DISTANCE THEREOF

摘要

A terminal for diagnosing failure of a communication line and a method for diagnosing the failure of the communication line as measuring a distance by using the terminal are provided to decide disconnected/short states of the line as exactly measuring a distance to a disconnected spot or a short spot, through a simple configuration based on previously inputted communication line parameters and measured line voltages. If a line state diagnosis menu key is inputted, a line connector(130) selects either a tip line or a ring line or a ground line to connect the selected line. A voltage measurer(120) applies a predetermined voltage to the selected line, and measures line voltages by selectively connecting plural resistance elements having different resistances. A program storage(113) stores a program which calculates line resistance based on the measured voltage, operates a short distance if the calculated resistance is smaller than predetermined resistance, calculates capacitance if the calculated resistance is larger, and which operates a disconnected distance if the capacitance is larger than a predetermined value. A resistance DB(114) stores resistance per unit length, and stores reference resistance compared with the calculated line resistance. A capacitance DB(115) stores capacitance per unit length, and stores reference capacitance compared with the calculated capacitance. A comparator(116) compares the calculated line resistance or capacitance with the reference resistance or the reference capacitance.