Digital dictation system with protection device against unauthorised listening - contains memory cards with stored codes accessible only by internal comparators controlling access to stored information

摘要

The dictation system contains mobile and/or stationary dictation devices as reception and/or reproduction devices contg. mechanisms for converting analogue speech signals into digital data and vice-versa and removable memory cards (2) with digital semiconducting memories (2.1). The memory contents of each card (2) are protected by using a freely selectable code written into a sub memory region. A reading block is lifted when a code passed to the card from a reproduction device coincides with the stored code. The stored code can only be read internally by a comparator (2.2), and is externally inaccessible. The code can only be replaced when the memory contents have been cleared. USE/ADVANTAGE - Digital dictation system prevents unauthorised access to stored information but enables authorized users to access it without requiring special decoding measures.