A data entry and/or operating system, particularly a keyboard, also a POS keyboard, includes a lower part and an upper part as well as at least one circuit board and at least one retainer plate, the retainer plate lying on the lower part. One or more bushings are integrated for the purpose of connecting the circuit board to the retainer plate. The upper part is formed from a rubber mat having keys, and the stability of the keyboard is assured by the circuit board, bushing and metal retainer sheet. The lower part is connected to the upper part in a sealed manner.