LG 42PA4500 Owner's Manual page 193

✎ This function is only compatible with devices having the SIMPLINK logo.
✎ To use SIMPLINK function,use high-speed HDMIⓇ cable (with CEC
(Consumer Electronics Control) feature added). High-speed HDMIⓇ cable has
No. 13 pin connected for information exchange between devices.
✎ When changing to another input, the SIMPLINK device stops.
✎ If a third-party device with HDMI-CEC function is added, the SIMPLINK device
may not work normally.
✎ [Depending on model] When selecting or playing the media of the device with
home theater function,
connect with Optical cable (sold separately) to use HT Speaker
HT Speaker is automatically connected. Be sure to
function.