If a MRT record does not contain unique record identification, then it is defined as a default record type. A default record type must be the very last record type defined. In addition, it should be defined as a recurring record. The Record ID Code Type, Location, Sub-field Offset, and Storage Size must be set to zero (0), one (1), zero (0), and zero (0) respectively. Furthermore, the Record ID Code must also be set to zero (0).

Please refer to "IQ Data Dictionary Reference" manual for a detailed description.