Step 1: Login IP Phone's webpage
Step 2: Setting->Date&Time, Time Zone:
For example:
Step 3: Click the "SaveSet" button ,The IP Phone LCD will display the time.
If the IP Phone LCD display the 00-00-0000 00:00:00, You need to check the following:
- Check the DNS(Webpage->Home), if the Primary DNS and Secondary DNS is 0.0.0.0, you need to configure this option:
For example:
Click the "SaveSet" button, and Restart the IP Phone. If the time has not changed, continues to the next point: - Check the NTP Server(Webpage->Setting→Date&Time):
You can change the System time on your PC
Then you can test other sever again, if the time period expired.
If the clock is successfully synchronized with time.nist.gov, You can copy the time.nist.gov and paste it into the appropriate location, then save the change.
If you don't want to configure this NTP Server, you can allow SIP Date Override Time.
Step 4: If you change the time zone, the IP Phone time is displayed incorrectly. You must check the following option because this DHCP Option 2 will to override Time Zone setting.
 Then the IP Phone will display the time you set.