A sysout DD statement makes an explicit reference in an OUTPUT
parameter that specifies the name of an OUTPUT JCL statement.
A sysout DD statement makes an implicit reference when it does
not contain an OUTPUT parameter, and the job or step contains one
or more default OUTPUT JCL statements.
A sysout DD statement implicitly references all step-level default
OUTPUT JCL statements in the same step.
A sysout DD statement implicitly references all job-level default
OUTPUT JCL statements when the step containing the DD statement does
not contain any step-level default OUTPUT JCL statements.
A sysout DD statement can explicitly reference a default OUTPUT
JCL statement.