Synchronizing Date and Time through SIP

You can configure the device to synchronize its internal clock (date and time) with a remote SIP endpoint (according to RFC 3261). When enabled, the device obtains the date and time from the Date header in the incoming 200 OK message received in response to a REGISTER request sent by the device. This can be any REGISTER request sent for normal SIP traffic handling (i.e., it's not a specific REGISTER message that is sent to a specific SIP server or endpoint). An example of a SIP Date header with date and time is shown below:

Date: Sat, 12 Mar 2020 23:29:00 GMT

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To configure clock synchronization through SIP:

1.

Open the Time & Date page (Setup menu > Administration tab > Time & Date), and then scroll down to the Date Header Time Sync group:

2.

In the 'Synchronize Time from SIP Date Header' [DateHeaderTimeSync] field, select Enable to enable the feature.

3.

In the 'Time Synchronization Interval' [DateHeaderTimeSyncInterval] field, enter the minimum time (in seconds) between synchronization updates. For example, if configured to 8640 (24 hours) and the device receives within this 24-hour interval a SIP response to a REGISTER with the Date header, it ignores the date. Only if it receives such a header after this interval does it update its clock according to the header, and then does the next update 24 hours later.

4.

Click Apply. When the device receives a SIP response with the Date header, it updates its clock and the date and time is displayed in the 'UTC Time' read-only field under the Time group (see Viewing Date and Time).