[ Version ( since = "0.4.0" ) ]
public string relation_type { get; set; }
A programmatic value that identifies the type of phone number.
For example: gdata_gd_phone_number_work or gdata_gd_phone_number_pager .
For more information, see the <ulink type="http" url="http://code.google.com/apis/gdata/docs/2.0/elements.html#gdPhoneNumber">GData specification</ulink>.