This instrument can be used for locating and searching the RJ11 telephone line or RJ45 network cable in a live working state. Line finding function: It can search for RJ11, RJ45, and other metal wires through an adapter. When searching for cable lines, there is no need to peel off the outer skin of the line, which is simple and fast, and the position of the line break point can be identified Wiring function: It can fully detect the wire sequence, open circuit, short circuit, incorrect pairing, and reverse connection of network cables.. Line level and positive and negative polarity detection. Telephone Line Status Detection: It can detect the status of telephone lines during work (idle, ringing, off hook) and detect the continuity (path) of TIP or RING line wires. General technical indicators Temperature range: Working temperature: 0-40OC, maximum relative humidity of 80 percent (non condensing). Storage temperature: -10-50OC, maximum relative humidity of 80 percent (non condensing, excluding batteries) Altitude: Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement.