Input message descriptor bytes (SLU P)

Message descriptor 1 (byte 2 of the FM header) has the following format.

Bit 0
Reserved
Bit 1
Page advance requested (NEXTPP)
Bit 2
Message advance requested (NEXTMSG)
Bit 3
Message advance protect requested (NEXTMSGP)
Bit 4
Next logical page requested (NEXTLP)
Bit 5
Reserved
Bit 6
Format description indicated by the MID name length, and MID name fields should be used to format this input message
Bit 7
Reserved

Bits 1, 2, 3, and 4 (MFS control requests) are mutually exclusive. Bit 6 must be set on if the input message is to be formatted by the MFS MID name provided. When bit 6 indicates a MID name is present, bits 0 through 5 must be zero.

Message descriptor 2 (byte 3 of the FM header) has the following format:
Bit 0
Version identifier for MFS DPM. Bit 0 must be set on if bytes 5 and 6 of the FM header contain the version ID.
Bit 1-7
Reserved