To upload transport files(of course also support packages) from Windows environment to UNIX System Services on IBM mainframe, we use transaction SPAM from client 000-->Support packages-->Load packages-->From frontend.
Before we used: ftp, commands in USS - iconv. But is was more complicated.
Transport files must be packed to .car or .sar. For example:
SAPCAR -cf ARCH_SAP.SAR cofiles*.* data*.*.We have in windows directory structure c:transcofiles and c:transdata with transport files. From directory trans we start command file SAPCAR_PAK.bat which contain only command:
SAPCAR -cf ARCH_SAP.SAR cofiles*.* data*.*. From transaction SPAM(client 000) we upload from directory trans file ARCH_SAP.SAR.Thats all.