I have been happily using a set of Belkin USB-serial converters for many years.  Because they're getting old and failing, and are also fairly bulky, I'm trying to move to newer devices.

I have some based on pl2303, ch341, etc.

What I'm finding, however, is that apparently they are coming out of the box with different sets of default CTS/RTS and other serial parameters, and they don't work with my serial interfaces downstream.

I haven't been able to Google my way to a solution: how do you manipulate the various serial parameters for a USB serial device.  I can't see anything I change with stty do anything, and I haven't had any luck with setserial either.

If anyone has some hands-on with this matter, I'd sure be obliged for some pointers.