Expert Documentation

The 500 DECT has no automatic or periodic process to synchronize its local date and time
with the OmniPCX Office system. When the NTP client feature is activated in the OMC, a
message is sent to the DECT Phone 500 to launch the synchronization process of its local
date and time with the OmniPCX Office system.
14.2.4.3 Synchronization process
When the initial NTP synchronization is activated in the OMC, see part 5.2 Configuration
Procedures, the system takes the date and time of the server and updates its own Linux clock
to have exactly the same time.
When the NTP client is running, the NTP process sends an NTP request every minute to the
designated time server. The response is used by the NTP process to adjust the local time to
the server time.
The delay of convergence depends on the difference between the server time and the local
time. The different cases are:
- If the server is unreachable (no replies to the NTP request), the client continues sending
requests to its reference server every minute.
- If the clock shift is less than 1 second for NTP, the Linux clock frequency is modified.
- If the clock shift is greater than 1 second, the answer is measured and the Linux clock
frequency modification is computed taking into consideration the previous response, With
the data the process is able to compute a gradual Linux clock frequency modification.
If the clock shift is greater than 10 minutes, the NTP client forces an initial synchronization to
update its server time. This synchronization is carried out instantly. After an initial
synchronization, the NTP process for smooth synchronization is continued.
Any initial synchronization is logged.
14.2.5 Topologies and synchronization
The following sections provide diagrams to describe the three main topologies that can be
used for a reference time server for a telephone network.
14.2.5.1 Synchronization with another OmniPCX Office
One OmniPCX Office is the time reference for each other OmniPCX Office in the system. Each
device sends the SNTP request to the OmniPCX Office to which it is registered, not to the
reference time server OmniPCX Office.
14-13