Editing of input message segments by MFS

If MFS is defined for a device, you should be aware of certain considerations.

The considerations include:
  • Specify GRAPHIC=NO in the SEG statement to prevent uppercase translation on a segment if the destination requests it with the EDIT=UC specification on the system definition TRANSACT macro.
  • If the first input record is from a 3600, SCS1, or SCS2 device, or from DPM-An, the segment is discarded if the final characters of the segment are:
    • Two asterisks (**)
    • Two asterisks followed by NL (**X'15')
    • Two asterisks followed by IRS (**X'1E')
  • The presence of two slashes (//) at the beginning of a message segment is considered an escape sequence.
  • If the card feature is defined for an SCS1 device (with the CARD=operand in the DEV statement), all control characters are removed from magnetic card input before the data is presented to the input MFLD.

The definition of the MFS delete characters (LDEL=operand in the DEV statement) and field tab character (FTAB= operand in the DEV statement) for MFS-supported devices, excluding IBM® 3270, can direct the editing of input message segments.

If the input is processed by MFS, the editing performed is dependent on the descriptions provided through the Message Format Service language utility. As input segments from the device might have no relationship to input message segments after MFS editing, the input segment from the device is not available to user-written edit routines. Input message segments after MFS editing are available to user-written edit routines.