What is time domain reflectometry?

The ability for handheld electronics diagnostics tools like the T3 Innovation Cable Prowler to identify the state of a wire simply by plugging into it is an immensely powerful technological advancement that has sped up the growth in size and complexity of networks. Without these useful devices, finding a shorted wire in a maze of cables connecting thousands of computers would seem nearly impossible. They do this through the use of Time Domain Reflectometry (TDR), or the measurement of electrical “reflections” along the wire.

Source: Blog.T3innovation.com