EPM HAVING AN IMPROVEMENT IN ACCOUNTING UPDATE SECURITY

摘要

An electronic postage meter has two non-volatile memories for storing postage meter accounting data under control of a CPU operating under a program in ROM. An accounting data recovery routine is stored in ROM. Prior to updating critical information in the non-volatile memories, a recovery address which calls the recovery program is stored in NVM and cleared after a successful update. At each power-up of the meter, the non-volatile memory is checked to see if the address is present and if it is, the accounting data is done again from the start of the accounting cycle.