1. A digital television (DTV) transmitter to transmit digital broadcast data, the DTV transmitter comprising: a transmitter that transmits a digital television (DTV) stream, the DTV stream containing an event information table (EIT) that carries a program schedule for a virtual channel, the EIT including a genre descriptor and a caption service descriptor, the genre descriptor comprising: a descriptor tag field identifying the descriptor as a genre descriptor; a descriptor length field, which is an 8-bit unsigned integer, specifying a length, in bytes, of fields which immediately follow the descriptor length field to an end of the genre descriptor, wherein the fields include: a category selection code, the category selection code being an attribute code value for an associated event in the DTV stream, the attribute code value specifying a basic genre or category type or detail attribute for the associated event in the DTV stream, and the attribute code value matching a value for the basic genre or category type or detail attribute in a categorical genre code assignments table defined in Advanced Television Standards Committee (ATSC) A/65 standard; and wherein the genre descriptor accommodates a plural attribute code values such that the transmitter transmits the plural attribute code values sequentially without intervention, and each attribute code value is defined in the categorical genre code assignments table that is ordered from basic genre or category type to detail attribute, and the genre descriptor references entries in the categorical genre code assignments table, and when a plurality of attribute code values are included in the genre descriptor, the basic genre or category type or the detail attribute code values are specified by 8-bit unsigned integer and at least one attribute code value is specifying a basic genre.