How To Activate HDMI ARC and CEC on Panasonic TV?
Activating HDMI Arc on a Panasonic TV is relatively easy and straightforward.  First, make sure that the television and audio receiver is connected via an HDMI cable.  The correct ports should be labeled as "ARC" or "HDMI-ARC" on both devices.  Once the connection is established, you will need to navigate through your Panasonic TV's menu system in order to activate ARC mode. On Panasonic TVs the HDMI ARC and HDMI CEC functionality is named "Link", so you need to navigate into your TV settings and have to find "ARC and Link settings" and from there, turn on the "ARC Link" option. Selecting that will enable HDMI ARC functionality between your TV and soundbar/receiver - allowing you to control volume levels with only one remote control.