Product description: This set of tools can be used for the installation, inspection and maintenance of various cable lines, and for the telephone line, it can judge the various states of the telephone line in operation, and is more convenient for the installation, debugging and maintenance of the telephone line. It works without letting you break the insulation of the cable. This set of tools includes a transmitter (sender MS6812-T) and a receiver (receiver MS6812-R). Features: 1. Determine if the cable line is continuous. 2. Track cable lines and identify where the line is broken. 3. Receive audio signals from the cable line (telephone line). 4. Determine the status (idle, ringing, off-hook) in the working telephone line. 5. Send a single audio or dual audio signal to the target cable line. Technical Parameters: 1. Audio signal: 1.5KHz. 2. Receiving frequency range: 100Hz-300KHz. 3. Battery supply: 9V (6F22) x1. 4. Receiver size: 238x43x26mm, transmitter size: 145x35x25mm. Packing List: Receiver x 1 Transmitter x 1 Instruction manual x 1 Bag x 1Specification: Package Weight One Package Weight 0.21kgs / 0.46lb One Package Size 25cm * 14cm * 5cm / 9.84inch * 5.51inch * 1.97inch Qty per Carton 48 Carton Weight 10.60kgs / 23.37lb Carton Size 42cm * 44cm * 52cm / 16.54inch * 17.32inch * 20.47inch Loading Container 20GP: 277 cartons * 48 pcs = 13296 pcs40HQ: 644 cartons * 48 pcs = 30912 pcs