The profile definition attribute descriptions are:
There is no default value for this attribute.
If you are running in a CICS system started with the VTAM=NO system initialization (SIT) parameter, the resource definition specified by Facilitylike must be defined as a remote terminal.
If you use the BMS forms feed option, specify YES.
RTIMOUT has no effect for MRO or basic (unmapped) APPC connections.
If you leave this field blank, CICSPlex® SM uses the default value for your CICS environment, if there is one.
The SCRNSIZE value is ignored if the TYPETERM definition has ALTSCREEN(0,0) and DEFSCREEN(0,0). That is, the screen size is assumed from the related TERMMODEL attribute in the TYPETERM definition; the page size is taken from PAGESIZE, and the ALTPAGE value is ignored. The 3270 erase write (EW) command is inserted for output requests with the ERASE option.
SCRNSIZE(ALTERNATE) may be used for all CICS service transactions (for example, CSMT).