RS485 Interface

Hi,

I would to use RS485 for my interfacing between PC and few other serial module.

What's the step should i start on the Hardware and Firmware(Protocol) side?
Example I had 3 node (node1=PC, node2=MCU1, node3=MCU2).
If i would like to use standard RS232 for all the node in interface, so i just have to put a RS485-RS232 convertor?
As i know the basic RS485 circuitry is show bellow.

Thank You.

if your destination hardware is not compatible with RS485 protocol then you have to use RS485 to RS232 converter.
But why you want to use RS485 when you can just use RS232? If you are thinking about how to connect many devices to singe RS232 line.. then take a look at the SBBUS, in which you can connect 255 devices on a single RS232 bus..
more specifications visit http://sbprojects.com/sbbus/sbbus.htm