How do I send band data to an Ameritron RCS-12

When I bought my 6600 I also ordered a FTDI Chip cable that was suppoed to output BCD band data. Part number C232HM to MPSSE Serial cable. I plugged the USB end into the 6600, I wired the GPiO; 0, 1, 2, 3, Vcc, GND to some LEDs. All GPiO are logic zero on all bands except for 20m where all outputs are logic One. How can send band data from my 6600 to the Ameritron RCS-12? The RCS-12 manual only illustrates Yaesu, Kenwood, and Icom. Yaesu does it thru BCD. I am sending band data to my amp via a USB-Null modem- USB Cable. The amp is looking for band data from a Kenwood TS-50. So the Flex looks like a Kenwood.