The National Emergency Number Association (NENA) identifies time keeping requirements for Public Safety Answering Points (PSAP) such as 911 call centers. These requirements include continuous accuracy of 100 milliseconds to UTC. PresenTense NTP Auditor actively monitors your computer for conformance to the NENA standard.
Typical time keeping scenarios include the use of GPS clocks to establish a traceable link to UTC and network time servers to synchronize site equipment via a local area network. In the United States UTC is provided by the National Institute of Standards and Technology (NIST) and the United States Naval Observatory (USNO). Various other countries define their own time keeping standards for sources of legal time. UTC is also known as GMT or Zulu time.
The NENA 911 standard requires display capabilities in 12 and 24 hour formats as well as status indicators that reflect the clock's current synchronization status with respect to the external UTC ( Coordinated Universal Time ) source.
The following status indicators are available for each external UTC source :
PresenTense NTP Auditor is locked onto and synchronized to the respective UTC source.
LOCKED, NOT IN SYNC
PresenTense NTP Auditor is locked onto the respective UTC source but the local clock is not synchronized to the respective UTC source. Statistical filters indicate that the network measurement is valid.
PresenTense NTP Auditor is locked onto the respective UTC source but the local clock may not be synchronized to the respective UTC source. A clock offset has been registered but has been discarded because of a large standard deviation value - network measurements are subject to excessive "white noise".
The respective status file "nena_primary.txt", "nena_secondary.txt" or "nena_tertiary.txt" was not found in the PresenTense NTP Auditor application folder or the file contents could not be read