We can produce voltage with R2R or not. It really depend the way we code it. The previous link didn't but tied resistor to GND.

You need to know which resistor value you need for each function on the radio side. And next step, do you need to tie them between the jack and GND or between the jack and VDD (5Volts). High like ln between the jack and GND. The previous link show and explain how it works.

Next you just need to play on the remote/steering side. Follow my code, it read AN0 and AN1, then evaluate ONLY AN0 value and jump to some routines.