By default the system is configured to use network time synchronization using the first analog trunk on the card installed in slot 1 of the system control unit. In that mode it gets its system time and date from the information that the line provider includes as part of the caller ID information. When network time synchronization is being used, system in a North American locale can also be configured to apply automatic daylight saving changes.
If the network time synchronization method above cannot be used on a particular system, it needs to be disabled. The time and date are then set manually. This is all done using a system administrator phone.