Date and time formats can be set on the phone and on the web interface.
Phone settings.
1. Press > Preferences > Date & Time > Date Format
Fig.1
The time setting affects phones and/or firmware versions with a digital clock only. If the phone has a clock face, changing the setting will not affect it.
Note: The time zone setting is accessible in admin mode only.
The phone receives the time and date from your NTP time server. If the time and/or date on the display are incorrect, you may need to set the correct time zone. If you have set the correct time zone and the time is still incorrect, there may be a problem with the time server. Contact your network
administrator or your IP provider.
The list of time zones is arranged by the difference in hours (+/-) to the UTC and, within each time zone, alphabetically by selected locations (country or country and city). Selecting and setting the time zone: