HT340G The cable tracker is designed to identify and trace wires or cables within a group without damaging the insulation. For telephone line， it can identify some state in the line， and more convenience to install， debug， maintain telephone line. There is a Sender and a Receiver included in the cable tracker. Judge continuity of the cables or wires. Track the cables or wires， and diagnose the break point. Receiver the tone signal on the cables or wires (telephone line). Identify the state in the working telephone line (clear ring， busy). Send a single solid tone or a dual alternating tone to the object cables or wires. Both products powered by one 9V batteries (Batteries included).