There are different possibilities of disabling CEC:
 
Method 1 - used if you have a mix of CEC and PUC controlled HDMI sources:
 
Set "HDMI Control" to "OFF" in the source setup on the HDMI connector in question. This will disable CEC in that one HDMI e.g. HDMI A, and CEC will still work on HDMI B-D.
Some CEC commands cannot be blocked this way. The TV is still open for certain commands e.g. source selection, which is why it is recommended to switch off CEC in the source (e.g. Blu-ray player) if possible.
 
Method 2 - used if all HDMI-connected sources are controlled with PUC:
 
If no CEC is used on HDMI A-D, we recommend disabling "HDMI Control" on all SoundCenter HDMI's (A, B, C & D) regardless if only one HDMI socket is used.
By disabling "HDMI Control" on all HDMI's, the CEC will be completely ignored by the TV when not in standby.
 
If this CEC setting/HDMI Control not taken into consideration when installing a TV, the connected devices can send CEC commands to the TV which will cause conflict with the PUC control and potentially cause unwanted behaviour like automatic source change or the TV switching on by itself.

thank you very much，it works 😁😁

BeoMegaMan wrote:

There are different possibilities of disabling CEC:
 
Method 1 - used if you have a mix of CEC and PUC controlled HDMI sources:
 
Set "HDMI Control" to "OFF" in the source setup on the HDMI connector in question. This will disable CEC in that one HDMI e.g. HDMI A, and CEC will still work on HDMI B-D.
Some CEC commands cannot be blocked this way. The TV is still open for certain commands e.g. source selection, which is why it is recommended to switch off CEC in the source (e.g. Blu-ray player) if possible.
 
Method 2 - used if all HDMI-connected sources are controlled with PUC:
 
If no CEC is used on HDMI A-D, we recommend disabling "HDMI Control" on all SoundCenter HDMI's (A, B, C & D) regardless if only one HDMI socket is used.
By disabling "HDMI Control" on all HDMI's, the CEC will be completely ignored by the TV when not in standby.
 
If this CEC setting/HDMI Control not taken into consideration when installing a TV, the connected devices can send CEC commands to the TV which will cause conflict with the PUC control and potentially cause unwanted behaviour like automatic source change or the TV switching on by itself.

Many thanks for the input :-)

Will try it out when I have a couple of hours to spare and can pluck up the courage.