OPTU structure definition

A unique 2-byte registered NJE key identifies OPTUs. Each OPTU includes a specific type and maximum number of data elements that represent keyword parameter values. The number of these parameters included in the OPTU is specified in a 2-byte count field that follows the key and precedes the parameter list:

key: Specifies the 2-byte registered keyword identifier. All values not defined are reserved for IBM's use and should not be specified.
cc(1-16383): Specifies the 2-byte count of the number of values supplied for the keyworkd parameter.
A count of 0 is used to indicate either a missing positional ] parameter or a defaulted parameter. For a count of 0, no data elements should follow the count field.
ll (1-16383): Specifies the two-byte length of the parameter value. A length of 0 indicates a null value.
For compatibility with MVS systems, the parameter length is restricted by the protocols to 128 bytes. Lengths greater than 128 will be correctly stored and forwarded by JES, but cannot be used at an MVS destination.
data: parameter value associated with the key.