Cocoon 1050 Cordless Phone

I can't find the manual for your device
The equivalent of buttons 2 and 15 from the previous procedure should be the buttons above the browser (central square button) or the touch buttons at the bottom of the screen

Do you have the manual for this device??

The humidity problem of the wall does not block a device... at most nothing works but the keyboard lock is a specific feature of the handset obtained by pressing and holding the # button
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 Very difficult to catch a black cat in a dark room.
 Especially when it isn't there...

Good evening
Excerpt from the Cocoon1150 manual hoping the procedure is the same

7.16 Keyboard Lock
You can lock the keyboard to avoid accidentally pressing keys. 
When the keyboard is locked, it is no longer possible to dial a phone number 
but you can still answer incoming calls.
To activate the keyboard lock: 

Press and hold the keyboard lock key # (key 7) for 3 seconds.* The screen displays the message "Keyboard locked" (Clavier verrouillé) along with the icon. To deactivate the keyboard lock: * Press "Unlock" (Débloc) (key 15) then press the keyboard unlock key # (key 7) to be able to use the keyboard again. </li></ul></pre>as for the Unlock key... 15 in this manual can also be key 2
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 Very hard to catch a black cat in a dark room.
 Especially when it's not there...