That it is authorized to write to a field "Email Address"

GW2012SP1 GroupWise Client.
Personal Address Book.
User can add new Contact in this Address Book.
For example:
Add contact: usertest1
"Full name:"="Test User Usertest1"
"Job Title:"="Test Job Title"

What it is authorized to write in this field: "Email Address" ??
How it will influence synchronization on "Novell Data Synchronizer" ?

Serg