If you do not code the FCB parameter for a data set on an impact printer, the system checks the FCB image that was last loaded in the printer; if it is a default image, as indicated by its first byte, JES uses it. If it is not a default image, JES loads the FCB image that is the installation default specified at JES initialization.

The FCB parameter names a default page definition to be used if the data set is line-mode, is printed on a page-mode printer and PAGEDEF is not coded on the OUTPUT or DD statements.