Hi Folks,
I have been troubleshooting a circuit attached below and could not get it to switch to ground when an input signal of 40kHz is sent from the Tx circuit. I have just realised that the Tone decoder I have installed is the LMC567 and I am unsure how this circuit works fully and what the calculations would be to work out Rt and Ct based on my transmitting signal being 40kHz. If anyone has any inputs of how to wire this LMC567 up and resistors sizes and capacitor size I would be very greatful.
regards
philip
attached is the circuit I was using. 
