In the project of “internet vending machine” we used almost standard qwerty keyboard and standard PC, so we needed to have possibility to be able to switch off keyboard during reboot, to disable CTRL+ALT+DEL and so on. These functions with a decent quality, until the death of the project, had been performing by “the keyboard interceptor” device. Interceptor is a device that is connected between PC and keyboard for keyboard data filtering. Device also capable to receive from external sensors and transmit to PC via serial port some data, to control some peripheral devices , but it’s main task, which consumes the most of it’s resources, is keyboard data filtering.