.. build my own USB to RS232 FT8U232AM
FTDI Home Page: “Welcome to FTDI – specialists in converting legacy peripherals to Universal Serial Bus ( USB ). We offer the easiest route to USB migration by combining USB Serial ( USB RS232 ) and USB FIFO silicon solutions with our ready-to-go royalty free USB drivers. FTDI’s ‘total’ solutions offer reduced development and debug costs and a fast time to market”
this may work:
just use the lines going to rxd and txd os rs232(serial)
to your 80535 rxd txd serial port lines.
http://www.hardwarebook.net/ for rs232 pin details.