I used to develop my signal master/slave smart card system by RS232(8051 urat).

As i want to change my system to muit-salve (5 slave) and the communication distance is also increased(10m).

I think using RS485 is an good idea for me.

After reading some material, i found that it should keep only one DATA PACKET on the RS485 bus. otherwise some data collosion error may occur.

My problem is how can i always keep only one data packet on the main bus.
My idea--

Add enable pin to each slave. and just enable only one slave at each time.
As the slaves may need to send out data at the same time. Some data may missing in the approach.

Any comment to me.

Thx

Mario