What test instrument is used to send out a test signal to identify cable faults?

The choice of the TDR, or Time Domain Reflectometer, is appropriate as this instrument is specifically designed to identify cable faults. It operates by sending a pulse signal down the cable and measuring the time it takes for reflections of the signal to return. This process allows the TDR to pinpoint the location of faults along the cable by analyzing the variations in signal return time and amplitude, which indicate issues such as breaks, shorts, or impedance changes.

Using a TDR provides detailed information about cable integrity, making it a highly effective tool for testing and troubleshooting in networking and telecommunications environments, where accurate cable fault identification is crucial to maintaining system performance. The precision and capability to locate issues along the entire length of the cable make it the preferred instrument for this purpose.