Data type: PtypBinary ([MS-OXCDATA] section 2.11.1)

The PidTagEntryId property ([MS-OXCPERM] section 2.2.4) contains an entry ID that identifies an Address Book object on an NSPI server. The entry ID MUST be formatted as either a PermanentEntryID structure, as specified in [MS-NSPI] and [MS-OXNSPI] section, or an EphemeralEntryID structure, as specified in [MS-NSPI] and [MS-OXNSPI] section<11> Messaging clients use this property to open an Address Book object. The client can then perform operations on the Address Book object, such as obtaining other properties. The types of operations that can be performed on an Address Book object are specified in [MS-NSPI] and [MS-OXNSPI] section 3.1.4 and in [MS-OXCMAPIHTTP] section 2.2.5. When the entry ID  is in Permanent Entry ID format, its DN MUST match the value of the PidTagEmailAddress property (section and MUST follow the format that is specified in section

The OAB Format and Schema Protocol specification, as specified in [MS-OXOAB], does not include value for the PidTagEntryId property for Address Book objects in its data structure. Instead, the PidTagEmailAddress property (section identifies objects in an OAB.