Elevator control centre. 
<ul><li>Logic scheme:
<ul><li>1)doors must open immideately if small mechanic resistance is detected;</li>
<li>2)cabin can't move, while doors are opened;</li>
<li>3)doors might be opened only if cabin is stopped perfectly on floor's level</li>
<li>4)cabin must be blocked, if doors are opened somewhere (except for servicing by specialists, when access to unauthorized persons is limited)</li></ul></li></ul>
<a href="//commons.wikimedia.org/wiki/User:Herr_Kriss" class="mw-redirect" title="User:Herr Kriss">Herr Kriss</a>
CC BY 3.0
<span class="int-own-work" lang="en">Own work</span>