rfc/cp_convert/conversion_char is a SAP Parameter attribute which is used to control default conversion character in case rfc/cp_convert/ignore_error = 1 information. This is available within R/3 SAP systems depending on the version and release level.
Below is the standard documentation available and a few details of the attributes values .
conversion character in case rfc/cp_convert/ignore_error = 1 the
conversion charcter is given by for characters describing its 2-Bytes
hex value.
this parameter only describes the default behavior that can be adapted
via sm59 for single rfc destinations
See SAP Parameter Documentation for full SAP documentation for this profile parameter.