How to change the system date and time. 

HOW TO CHANGE THE SYSTEM DATE AND TIME
With your phone idle and the handset on-hook, complete the following steps

  • Press [TRANSFER] and Dial 200

  • Enter the password 1234

  • Press 1 to Enable

  • Press Speaker and dial 505

  • Enter the day of the week (Monday is 1, Tuesday is 2, Wednesday is 3, etc.)

  • Enter 2 digits for the month (March would be 03)

  • Enter 2 digits for the date

  • Enter 2 digits for the year

  • Enter the hour in 24 hour format (9 am is 09, 3 pm is 15)

  • Enter the minutes

  • Press [TRANSFER] to save and exit