How does this cable tester work?

Question

Computer networks

There is such a device, but there is no instruction for it. It is not known whether it is correct or not.
Please explain how to test this thing and how it works. Specifically, I need to find the other end of the cable

Answer 1

If there is no reciprocal part and the ends of the cable are far apart, then the device is useless, it’s easier to ring with a multimeter.