When you enter the right code, it sends a short mesecon signal to the block behind it (like a mesecon button).
It is advised to use a protection mod like protector or node ownership, else everyone is able to break it and change the code.
But, if you don't want to use one, please tell me so I make it unbreakable without the right code (or only breakable by the placer).
Crafting:
License: WTFPL (applies to all parts)
Depends: default, mesecons
Screenshot (click for full size):
Download:
v0.2 (for latest mesecons)
v0.1 (for older mesecons)