I am using osx-pl2303 driver with ATEN-UC232A and macbook with OSX version 10.4.10. My kernel version is:
Darwin Kernel Version 8.10.1: Wed May 23 16:33:00 PDT 2007; root:xnu-792.22.5~1/RELEASE_I386 i386 i386
When I try to turn off hardware flow control in minicom, it has absolutely no effect, hardware flow control remains on. It works with the ATEN driver, but osx-pl2303 is superior in every other area, for example I can send a break signal with it.