Time synchronization
From Zenitel Wiki
Contents
Synchronizing using a NTP server
The AlphaCom can synchronize its real time clock with Network Time Protocol (NTP) time servers on the IP network. The syncronization is taking place once every hour. To activate the feature, define the IP address of a valid NTP server in the Time and Date settings in AlphaWeb.
If the AlphaCom is connected to the internet, you'll find a list of NTP servers here: http://support.microsoft.com/kb/262680
The NTP uses port 123 so this port must be opened on a firewall or router to ensure proper communication with the NTP server.
Synchronizing using GPS network
GPS (Global Positioning System) is a world-wide satellite system that operates a time scale and transmits information for synchronizing to UTC (Coordinated Universal Time) with extreme high accuracy. The AlphaCom can syncronize its real time clock with a Master Clock which receives its time from GPS satelittes. The Master Clock 70000L has an embedded NTP server, to which the AlphaCom synchronizes.
Synchronizing using Radio signal
DCF 77 signals transmitted from Germany is the most frequently used signal in Europe. The signal is sent every minute and comprise minute, hour, year and date.
In France the national TDF transmits signals for time synchronization and in Great Britain the MSF-Rugby sends similar signals for synchronization. RDS is a signal transmitted over the FM band in Scandinavia.
Many other European countries have national signal system which includes time data and which can be used for time synchronization.