Solution
To lock/unlock the infrared remote control, enter 1,1,6,9 on the remote control and press OK.
To lock/unlock the remote control keypad, enter 1,1,6,8 on the remote control and press OK.
"What are the remote's button functions for the DVLED display?"
"Why is the DVLED Display remote control having trouble with sensitivity or not working?"
"LED Display | How to use the remote properly"