LG DU-52SZ40D Owner's Manual page 22

7. Screen 5: Which TV input is the cable box plugged into?
•If you select Cable, you see Screen 6.
•If you make any other choice, you see Screen 7 .
8. Screen 6: Cable Box Tuning Channel
•Select the channel used for the cable box.
•Press ENTER to display Screen 7.
9. Screen 7: Cable Box Configuration Diagram
•The diagram shows the correct way to install the G-LINK Cable from
the back of the device to the cable box.
Make sure the G-LINK Cable is properly installed.
•Press ENTER to display Screen 8.
Installation
Owner's Manual