| • |
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 |
