This code defines the unique key in the contact record. This key can be manually assigned or if it is not entered, it can be defined via the CCN sequence number counter.
By default, this counter is constructed of a sequence number made up of 15 characters. To ensure the correct functioning of the Contact object, it is strongly advised to conserve these standard characteristics.
From this area, it is possible to associate with the Outlook contact a contact referenced in the base, to access the detail of a contact record and also to launch a contact search.