Deus Ex: Human Revolution encourages you to Hack the locked doors and devices to unlock them and get access to whatever you need that’s hidden inside. There is another way to unlock these locked devices and doors, and that is by using the key codes or password for that particular device or door.
You can find these pass codes hidden somewhere in the same level, and input the digits simply and bypass the hacking process. There is a catch though, Hacking results in XP while unlock the doors and devices using pass codes gives you no XP.
Note. If you are interested into devices/locked doors, you should read our Hacking guide to get you started.