This summer, we were on vacation in Europe. On our return trip, we had some time to spend at the TFN airport on Tenerife island. I was glad that my daughters went to the playground while my wife was shopping, so I could relax before the flight. Then I noticed that our oldes daughter had started to explore one of the arcade game machines in a way probably not intended by the manufacturer.
I saw her tilting the front panel of the machine and putting it back in an upright position so that the game (and especially – the music) would start again. Intrigued by the movable front panel, I got up and took a closer look. It appeared that the front panel was not locked as intended, but could be moved. The computer inside the casing detected when the front swung open and reset itself. More exactly, it showed a service menu first, and reset itself when the panel was closed again.
Having worked with user interfaces for embedded software in the past, I was interested in how the manufacturer dealt with service access. At the top of the screen there was some information:
- (Device?) ID: G16B000084E8
- MAC_ID: (empty)
- Hardware: 013.XP.ETX (Windows XP Embedded?)
- Interface: C 6.9
- versión: R1.4.0 FSS: 140
- Build: HKF4.016.000
Further down, the menu showed eight buttons (English translation in parentheses based on my limited knowledge of Spanish and supported by translate.google.com):
- Monedas (coins)
- Información sobre el equipo / Ajustes (information on the equipment/adjustments)
- sonido (sound)
- estatistica (statistics)
- pantalla táctil (touch screen)
- publicidad (advertisements)
- Opciones de seguridad (security options)
- Highscores (highscores)
I had seen my daughter pressing some buttons earlier, so she demonstrated what happened when on chose an option. Apart from calibrating the touch screen, all options were protected by a PIN code. We tried several PIN codes, but neither 1234, 123456 nor 111111 worked. Random pressing of codes did not help either. After a while, the device decided that there must have occurred a malfunction or an intrusion. 
The screen went black and displayed a message that an incorrect PIN code had been entered. A clock started to count down from 23:59:59. Closing and opening the front panel did not change the situation, so we decided that it was no longer fun to try our luck with the machine. Our flight was about to leave soon afterwards, so I have no knowledge what happened to the machine after the countdown had reached 00:00:00.
The hardware seemed to be a standard x86 personal computer with a coin insertion mechanism connected to the serial interface. I did not try to open the DVD tray, as I did not want to break or steal anything (and I did not want to teach my daughter that it would be ok to remove DVDs from a machine positioned in a publicly accessible area).
While we played with the front panel and the service menu, several airport employees passed by, but none of them took any interest in what we were doing in the ca. ten minutes we had undisturbed access to the machine.
