FYI ... DRDA debug.

All IBM Data Server drivers use the DRDA protocol to communicate with the database server.
ODBC Trace - http://www.redbooks.ibm.com/redbooks/SG247884/wwhelp/wwhimpl/common/html/wwhelp.htm?context=SG247884&file=08-30.htm

Use Informix ODBC Driver with an ODBC Driver Manager - https://www.ibm.com/developerworks/data/library/techarticle/dm-1108odbcdrivermanager/index.html#resources

Kind regards,
Vadim.