The SAP NetWeaver RFC SDK is provided to enable communication between non-SAP programs and SAP applications based on SAP NetWeaver ABAP. For the operating system IBM i, the SAP NetWeaver RFC SDK comes in two different flavors: An EBCDIC version for single byte languages in the Latin-1 character set (ISO/IEC 8859-1, Western European languages), and a Unicode version supporting all countries and languages.
SAP Note 2573953 contains information about programming considerations, and how to compile and link programs using the SAP NetWeaver RFC SDK 7.50.
If you compile and link programs with the Unicode version of the SAP NetWeaver RFC SDK, you need the ASCII Runtime for IBM i, which is provided in a library called QADRT. The ASCII Runtime for IBM i can be downloaded from IBM, but the download link has recently been changed. It is now available at
https://www.ibm.com/support/pages/node/6258183. Select the tab "Development kit" to get detailed download and install instructions.
Note that the ASCII Runtime for IBM i is only needed when you compile and link programs for the Unicode version of the SAP NetWeaver RFC SDK. The necessary parts to execute programs containing the Unicode version of the SAP NetWeaver RFC SDK are shipped with the base operating system.