LG M4210LG Owner's Manual page 68

Make sure to read the Important Precautions
before using the product.
Keep the User's Guide(CD) in an accessible
place for furture reference.
The model and serial number of the SET is
located on the back and one side of the SET.
Record it below should you ever need service.
MODEL
SERIAL
Temporary noise is normal when powering
ON or OFF this device.