HOW TO CHANGE THE TIME ON THE TOSHIBA DK280
Click here to download this user guide in PDF format 
The time and date MUST be set from the Main Extension (This is typically extension 10 or extension 200)
To Set The Date:
1) Press Intercom
2) Dial #651
3) Dial the Date in the following format: (YY/MM/DD)
4) Press the Redial button
5) Press the Spkr button
To Set The Time:
1) Press Intercom
2) Dial #652
3) Dial the Time in the following format: (HH/MM/SS)
4) Press the Redial button
5) Press the Spkr button
To Set The Day:
1) Press Intercom
2) Dial #653
3) Dial the Day in the following format:
1 = Sunday
2 = Monday
3 = Tuesday
4 = Wednesday
5 = Thursday
6 = Friday
7 = Saturday
4) Press the Redial button
5) Press the Spkr button
The new time should appear in the display of your Toshiba telephone