Undocumented commands and functions

Long time ago as I was learning about George Boole  algebra I immediately though about using a (hidden) sequence of button presses to lock and unlock safes, doors, etc.  In addition to setting arbitrary sequences of button presses, I had the idea of taking into account the time spent on pressing each button which would have greatly improved the safety of the device. As I had so little to hide away from the villains eyes, my motivation faded away and so did the project for the unlimited door lock.

Although this approach looked very trivial, it is still a very valid approach to hiding specific functions or commands from ordinary users, vulgum pecus so as to say. As I was struggling with my ol’brave HP3050 printer (HP3050A  J611 Series to be precise), I tumbled on the web and found that undocumented functions were hidden and only available through a sequence of keystrokes (actually X sign , return sign, X sign twice and you’re done), just the good’ol way !

And that’s definitely the way I would approach the setting of parameters for any embedded system. To the cost of few pins and a bunch of bytes of code.

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