Flex USB-RS232 cable works (almost) with Tokyo Hy-Power amplifier. To remotely band switch the HL-1.5KFX amplifier, I connected the UTR232R-200 cable from one of the USB ports on the Flex 6500 to the RS-232 port marked "Kenwood" on the amplifier. Use standard settings of 9600-8-n-1, and place Band Select switch in "Kenwood" position. In SSDR (v18.104.22.168,) go to Settings - USB Cables, and select "CAT" as the cable type, and "TX Slice" as the Source. The standard cable from Flex requires a M-F Null Modem adapter to swap the TXD and RXD pins, but other than that it's a real simple solution. My HL-1.5KFX amplifier does not require full 100 watts input to get the rated 1000 watts output, so I have max TX power for the Flex 6500 set to 90 watts - and reduce that output power to 70 watts on CW and DIGU modes.