Method and apparatus for securely resetting a real time clock in a postage meter

A value dispensing system includes: a printing mechanism for printing an indication of value; a microprocessor including a real time clock mechanism, the microprocessor initiating printing of the indication of value by the printing mechanism; a device for electrically connecting the value dispensing system to a primary power source and for utilizing power received from the primary power source to operate the microprocessor and the printing mechanism; a back-up power source which supplies backup power to the microprocessor to enable continued operation of the real time clock only when the value dispensing system has been disconnected from the primary power source; wherein the microprocessor is programmed to 1) disable operation of the printing mechanism upon a failure of the backup power source and in response to reconnection of the primary power source to the value dispensing system, 2) require resetting of the real time clock as a prerequisite for reenabling the operation of the printing mechanism subsequent to its disablement by the microprocessor, and 3) only permitting the resetting of the real time clock subsequent to inserting a real time clock security card into the value dispensing system.