PonyProg will not ever work with USB-to-Serial converters. The point is that PonyProg use bitbang method and just switches RS232 port pin levels to generate a special sequence. It is nothing common there with the RS232 standard itself. Check the FT232 GPIO pins. It is possible to do a programmer using those pins without any additional chips, so it is the same bitbang method.
PonyProg will not ever work with USB-to-Serial converters. The point is that PonyProg use bitbang method and just switches RS232 port pin levels to generate a special sequence. It is nothing common there with the RS232 standard itself. Check the FT232 GPIO pins. It is possible to do a programmer using those pins without any additional chips, so it is the same bitbang method.