The ibmdisrv startup script starts the TDI server without altering its default encoding, which on z/OS is EBCDIC (IBM1047). In order to run the server on z/OS in ASCII mode start it using the ibmdisrv_ascii startup script. This script starts the server with its default encoding set to ASCII (ISO-8859-1).
In ASCII mode, the server ignores the global.properties file. Only the solution.properties file in your Solutions Directory is used, and this file needs to be encoded in the ASCII character set.
Encoding of solution.properties
Altering the default encoding of the TDI server affects how the solution.properties file is read. That is why the encoding of the solution.properties file in your Solution Directory must be changed to ASCII before starting the TDI server in ASCII mode. The location of the solution.properties file is your_solution_directory/solution.properties.
Changing the encoding of a text file on z/OS
The standard iconv utility available on z/OS can be used to convert the encoding of a text file. Starting the iconv utility with no parameters on the z/OS prints usage information.
The global.properties file
When the Server on z/OS is run in ASCII mode the global.properties file is ignored and only the solution.properties file in your Solution Directory is read. That is why have all the required properties for the solution in the solution.properties file in your Solution Directory.
Log files
When the Server on z/OS is run in ASCII mode the server log files are encoded in ASCII when being written to the file system. That is why in order to read these ASCII log files you might have to first convert their encoding to the native encoding on z/OS, which is EBCDIC (IBM1047).
Console output
When the Server on z/OS is run in ASCII mode any text output to the z/OS console by the server appears garbled. This is caused by the output text being encoded in ASCII while the console expects the text to be encoded in EBCDIC. In order to read the server output to the console, the server output can be redirected from the console to a file and then this file can be converted from ASCII encoding to native encoding on z/OS (EBCDIC).