If when you press the lock opening button, the corresponding LED flashes several times without controlling the lock, the secure locking mode is active on your Classe 300 EOS, i.e. the buttons are only active if there is an audio/video connection in progress between the videophone and the external keypad. To deactivate the secure locking mode: - remove the Classe 300 EOS from the wall bracket - remove the green power supply terminal - move the secure locking function microswitch located on the back of the videophone to the correct position - reinsert the green power supply terminal - reposition the videophone on the wall bracket This operation must be carried out by an authorized person.