MFS control requests

When Message Format Service (MFS) is used, MFS control requests can be used to display paged messages and to control the display component screen.

The control request is specified in the input function management header.

DR1, DR2, or exception DR1 and DR2 can be requested. Using exception DR1 or DR2 is recommended, because the additional line transmission required to send DR1 or DR2 and the completion message can be eliminated if the controller requests exception DR1 or DR2.