In reality the RS232 is designed to connect generally ONLY two devices toghether.

The RS485 have the capability to manage multiple slave and one master.

In my project I have one master and I connect the USART to the RS485 chip and then in daisy chain all the other RS485 chip to the USART's slave. But that means every slave have his proper address, manage receiving, CRC chek etc etc and to do in the best way is needed a protocol.

Googling I have found the SNAP protocol ( http://www.hth.com/snap/ ) that shall be good to be implemented in my solution and have the source code in PBP (old version).

If I do not found a protocol more simple than SNAP, I will study and implement it.

Leo