- Verify that the terminal is properly connected (mains cable or battery for a portable terminal).
- Unplug the mains connector of the terminal.
- Leave the terminal without current for 30 seconds.
- Press successively on all of the buttons in case one of them is stuck.
- Put the mains connector back in the socket.
- If you have a portable terminal:
- Remove the battery.
- Wait 30 seconds.
- Press successively on all of the buttons in case one of them is stuck.
- Put the battery back in place.