Time Zones

Topic Last Modified: 2006-06-12

Appointments are stored in the Exchange store and are based on coordinated universal time (UTC). When you view an appointment, you need to convert the appointment to local time. Clients such as Microsoft® Outlook® automatically convert appointments to the local time of the client computer.

Collaboration Data Objects (CDO) automatically converts date and time values in the properties of CDO to local time. CDO does this based on the time zone information in the corresponding CDOConfiguration object. When you save an appointment or create a calendar message, CDO converts the local time specified in the StartTime and EndTime properties of the Appointment object to UTC, based on the time zone information in the Configuration object. When CDO expands recurring appointments into individual instances, it uses the time zone information from the Appointment object.

Date and time values in the Fields collection and in the stream of CDO are converted to local time. This is done by using the time zone information from the Configuration object. By default, the CDO Appointment and Configuration objects use the system time zone value from the computer that is running CDO.

For example, you are in Brussels ( UTC + 1:00 hour) and you want to schedule a telephone conference with colleagues in Bangkok ( UTC + 7:00 hours). You create a meeting for 9:00 A.M. local time and send a meeting request. The appointment is stored in Microsoft Exchange Server 2007 as 08:00:00 UTC. When your colleagues in Bangkok view the appointment, their calendar client programs convert UTC to local time and display the start time as 3:00 P.M.

You can also create floating appointments. Floating appointments are appointments that are not adjusted for time zones. For example, you may want to have an appointment on your calendar for lunch every day from 12:00 noon to 1:00 P.M., regardless of the time zone. You would not want lunch to convert from noon to 6:00 P.M. when you travel from Brussels to Bangkok.