This policy setting enables you to customize the 3rd value of the Contact Tab. If you enable this policy setting, you can ...

This policy setting enables you to customize the 3rd value of the Contact Tab.  

If you enable this policy setting, you can change or remove the default value "work phone" of line 3.

If you disable or do not configure this policy setting, the default value for line 3 is displayed.
 
Important:
It is recommended that you specify a Messaging Application Programming Interface (MAPI) property and a corresponding Active Directory attribute (AD attribute).  The MAPI property should always be specified, unless Outlook is not installed, in which case only the AD attribute needs to be specified.  It must be entered in this format: ADAttribute.  Any properties entered which are binary or list box, cannot be displayed and are ignored.

Example:
To display the Assistant on the Contact Card, enter the AD attribute: Ms-exch-assistant-name

To remove the value, enter: null.

Note: 
The Location and Calendar values for a default Contact Card are not MAPI Properties or AD Attributes.  

Related policy settings:  
Contact Tab: Move Calendar Line, contact Tab: Move Location Line, Contact Tab: Replace Label - "label", Contact Tab: Replace MAPI property - "property