To enable a TV onto a specific channel or to enable/lock very specific features, you need the hotel mode. Most TVs have this kind of mode. It can be entered via standard remote controls, special key combinations on the TV, special programming remote controls or interface cards. On newer TVs probably also via USB, ethernet or other means.
On the Panasonic Viera TH-42PV60 do the following:
- On the TV, hold the button "- / V" pressed
- Press "TV/AV" three times ON THE REMOTE
In case you have a different model, try "TV" three times, followed by "AV" three times.
To exit, the menu, press the exit button on the remote control. Followed by putting the TV into standby and switching it properly off.
Make sure, you don't disable the remote control in the hotel mode. Otherwise you will have to google yourself how to enable it again (maybe let me know then)