How Do I Enable ActiveSync on My iPhone?
You can easily enable the ActiveSync feature on an iPhone to sync your Microsoft Outlook items with your iPhone. An example is that when you update contacts in Outlook, then it will update automatically on your iPhone as well when syncing the two applications. To use ActiveSync, you must know your email account information and the name of your Exchange Server.
Turn on your iPhone to the home screen and the press on the “Settings” option. tap the “Mail, Contacts, Calendar” option. Select "Add Account" if you have already setup an email or calendar account on the iPhone. Select the “Exchange” option.
Type your email address in the "Email" field and its password in the "Password" field. You can change the description if desired. Press the “Next” button. Allow time for your iPhone to verify the settings.
Choose the Exchange server that you want to sync with your iPhone. If it does not appear automatically, you may have to type the Exchange server's front-end Web address in the "Server" field. Contact your network administrator if you don't know this address.
Select the items that you want to sync to your iPhone from Outlook, including calendars, notes or contacts. Tap the “Save” option.