TIPTEL IP 286 Manual page 22

Enterprise IP Phone Customizing Your Phone
To set the time format via phone interface:
1） Press Menu->Settings->Basic Settings->Time & Date->Time & Date Format.
2） Use the Switch hot key to choose a preferred time format: 12 hour or 24 hour.
3) Use the Switch hot key to choose a preferred date format, the IP phone can support
7 kind of date display format.
4) Press the Save hot key to save the changes and return to the previous screen.
To change the Time and Date via the Web interface:
Choose Phone->Preference to do the relating changes. You can also change the Update
Interval which specifies the time frequency that the phone refreshes the time
automatically. Please refer to the instruction above for the parameters' detail.
To change the Daylight Saving Time Settings via the Web interface:
1) Choose Phone->Preference->Daylight Saving Time to do the relating changes.