Just verified that my THP HL1.5KFx works with a FTDI USB cable connected to my 6500. The only issue: the amplifier RS232 port is female, but requires a null-modem cable and gender bender to connect and work. Default settings of 9600 baud / 1 stop bit are appropriate.
Note that the amp changes bands only after a frequency change on the radio.
Note that the amp changes bands only after a frequency change on the radio.