Answer: Time-domain reflectometer for copper cabling Optical time domain reflectometer for fiber-optic cabling
Explanation:
Time-domain reflectometer(TDR) is defined as the device that is utilized for locating and identifying any breakage and faults in circuit board, wires,connectors,metal cables or any path of electricity.
Optical Time Domain Reflectometer (OTDR) is the electronic device that searches and locates faults and break in fiber optic cable.