The Global Address List in Exchange Server contains the contact data from all mailboxes and contacts in a company. The GAL might be searched online from many devices, but offline synchronization and Caller ID resolution are not available. The address book entries can be fetched by PeopleSync to bring them to your Windows Phones or other apps and devices. PeopleSync will retrieve phone numbers, addresses and even the profile pictures, stored in Active Directory. PeopleSync will work with Exchange Server 2010 and 2013 as well as with Office 365 Exchange Online.
To synchronize your Exchange Server GALs from messageconcept PeopleSync to your Windows Phone, you can use the CardDAV protocol. CardDAV is a standard for the synchronization of contacts between apps and devices. The standard is supported natively by Windows Phone 8 and Windows Phone 8.1 to support Google Gmail and Apple iCloud accounts. By simply configuring these account types to the URL of your PeopleSync Server, you will be able to sync your Exchange Global Address List and other sources to the Windows Phone. A roll-out of an app is not needed.