yes, you can. The only condition is that you make the 422 shut up when the 485 is talking by some software means. The other thing you will see is that the 422 will be hearing itself since you parralleled the transmit and receive lines, that may need to be taken care of too. Again, you can make it work if you have access to the software on both sides. If you have hard- and software access on the 485 side, you can, of course, convert that to 422. I have seen very few 422 2 wire (wire - not pair) systems, if yours is such, you are in luck, connet the buggers and GO.

Have fun,

Erik