To Set Date/Time/Time Zone on Verifone P400 please follow the step below.
1. On Home Screen, Press 1-5-9 at the same time.
2. Press Control Panel
3. Press Sysmode
4. Press Supervisor
5. Enter 1668321
6. Press Administration
7. Press Date/Time
8. Press the Box on screen you want to change, enter change then press Green Key (See Picture)
9. Box Choices are Date/Time, Time Zone and Auto Reboot Time.
10. When complete, Press Red X button twice to Screen with Information on top row.
11. Press Exit then Reboot.