MFFTP_CLIENT=USER
A user-written module which is specified using MFFTP_USR_FTP_PGM invokes the third party program.
MFFTP_USR_FTP_PGM=module
This configures MFFTP to call the specified module, that will invoke the third part client.
If MFFTP-CLIENT is set to USER, MFFTP_USR_FTP_PGM must also be set and must name a module that is accessible to the batch process. If these conditions are not met, MFFTP aborts after validating the control cards.