COMPARATOR WITH ENCRYPTION SYNCHRONIZATION STORAGE
Original Publication Date: 1997-Dec-01
Included in the Prior Art Database: 2002-Jun-13
In a secure digital voting system, there can be subscriber and console audio present at the same time. Only one of two sources will be repeated, whichever is configured in the comparator to have higher priority. If the higher priority signal ends while the lower priority signal is still present, the comparator resumes to the latter. This means that subscribers receiving the call will hear the end of one call and then start hearing the middle of the lower-priority call. In current systems, the encryption module for the subscriber is unable to start decrypting properly until it receives encryption synchronization (ESYNC), which for example only gets put out every 360 ms in APCO-25 CAI. The user could experience an unacceptable amount of truncation in the form of silence or improperly decrypted audio. For protocols with longer times between synchronization, this becomes even more of a problem.