Indicator positions:

The first two character positions in the variable data fields that contain values which interpret or supplement the data found in the field. Indicator values are interpreted independently, that is, meaning is not ascribed to the two indicators taken together. Indicator values may be a lowercase alphabetic or numeric character or a blank (ASCII SPACE). A blank is used in an undefined indicator position. In a defined indicator position, a blank may mean no information provided or no information available.