Switch on the powet, which works if the light flashed
Once Switched on , LEDS of the remote tester will scan the cable accordingly .
If the cables are good . The Corresponding LEDS will turn Green Sequently.If the Cables are out of work, the LEDS Will first turn Green then red or other Colours, LEDS will not be on or be on Disorderly.
Adjusting the Speed Knob will Change the LEDS Flash Speed, It helps Seeing the LEDS state.