When entering an ACS installation exit, ACSPERW points to a list of read-write variables which are mapped by IGDACERW. Initially the list of read-write variables contains the original value for the SMS class that was assigned in the ACS routine. To assign an SMS class from an ACS installation exit, your routine must, in IGDACERW:

• Set the ACERWNCS field to one. This field specifies the number of SMS classes to be assigned. The valid values for this field are zero and one. Initially, it contains a length value based on the logic in the local ACS routine. If more than one SMS class is returned, only the first is accepted.
• Set the ACERWVLN field to the actual length of the SMS class name. Trailing zeros and blanks should not be included in the length. Initially, this field contains the length value of the SMS class being passed from the local ACS routine.
• Set the ACERWVAL field to the name of the SMS class being assigned. Initially, this field contains the SMS class value passed from the local ACS routine.

To assign a null value to an SMS class, you must set the ACERWNCS field to one and the ACERWVLN field to zero. The ACERWVAL field is then ignored. If you do not want to assign a class, set both the ACERWNCS and ACERWVLN fields to zero.