APPARATUS FOR PROTECTING DATA IN NON-ENDURABLE READABLE/WRITABLE MEMORY

摘要

The use of a volatile random-access memory (RAM) for storing tariff data and variable control counter data in a taximeter presents considerable advantages if a circuit for permanently saving the data stored in a RAM can be found. In the circuit according to the invention, the signal line (16) is run between the microcomputer system (1) and a volatile random-access memory (RAM) (10) via a control circuit, by which a permanently effective suppression of input commands can be set when the taximeter is in a sealed state. Consequently, the data stored there can no longer be influenced by unwanted signals from the microcomputer system (1). The operating voltage supply to the RAM (10) is protected by a circuit (20 to 26) incorporating a back-up battery (23) and a back-up capacitor (24). IMAGE