Minecraft wiki entry for Telegraph, associated text: The only situation that a button could be used is in a one-way telegraph system for distress signals to other players in multiplayer. However, the receiver would not remain activated due to buttons automatically returning to the 'off' position after only 0.9 seconds. It is also a small target to aim for, especially when a player is in the kind of situation that a distress signal seems like a good idea. So when it comes to telegraphs, use of buttons should probably be avoided entirely.