Problem: FT-450 cables cannot work because RTS causes TX

I got a unit for my FT-450D, with cables.
Problem is, the FT-450 requires RTS to be high, for the CAT to work. But when I set RTS high in the software (VarAC in this case) the transceiver goes into TX, because of the audio plug ring 2 being switched to ground.

So, for my radio I must break that connection. However, from what I see there is no simple way of doing this, or am I missing something?


I could possibly try to remove resistor R15, but I have no idea where on the board that is…

The RTS signal of the Digirig’s serial port is not connected to the radio so there is no point in activating it. The RTS on the radio’s side is looped to the CTS so it appears active any time radio is ready to receive the data. There is noting that need to be changed in wiring for that. If the serial communication doesn’t work then issue is likely with the configuration.

EDIT: I see you are asking about about Yaesu, not Kenwood, the hardware flow control loop though is the same (pins 7 & 8 in the DB9 are shorted in Digirig serial cable).

Thanks for that.
I found in the meantime that there is a setting in the FT-450 to disable the RTS under Digital settings. This prevents the tranceiver going to TX when the RTS goes high. Because when I did NOT force the DTR high, the CAT would not work!
Anyway, by disabling the RTS causing a transmit, I now got it all working.

Thanks for your help,