Rrad about a complex remote control unit using VLSI circuits and made
some considerations.
Using a 9V transformer it is possible to switch relays to 4 positions
using the following signals on the antenna cable - with RF chokes and
suitable capacitors to pass the RF, and two dpdt relays at remote end:
1) no voltages
2)+12V with a diode in series with the switch and transformer
3) -12V with another diode in series with switch and transformer
4) 9VAC to activate both relays simultaneosly

very simple, but no VLSI - if that was the point, and no intruder
transmitter on 433.92MHz for the remote control if it was another
point, sorry - I am perhaps to old for those modern type of remote
control......

73
Jan-Martin
LA8AK