I had a similar setup. You need to make sure the camera address is set. If you have only 1 camera, set the switches to 0, so camera address will be 0.
Your USB to RS422/RS485 converter will work if wired correctly, ie. be sure the send line low and high on the converter are wired to the recieve low and high on the camera.
I used a shareware program called PTZ controller. It is easily available on the internet, first 30 days use are free, after that you have to pay.
Find out which com port your converter is emulating by using Device Manager in windows, look for Ports, and see what number port you are using.
In the PTZ software, set the proper com port, 4800 baud, and select the
AD-RS422/485 protocal.
Also, open the Camera window and select the address of the camera, ie. 000.
Put your mouse pointer on the center of the little screen the software provides, hold the left mouse button down and move the mouse. Cam should move. If not, check your wires.
Enjoy.