Thanks for your fast replay,
well i tried last night connecting master using SerialPort Library then take serial signal to mentioned IC (SN7...) for bus then connect it to RX and Tx of the Slave
and it is good for sending from master to slave's as the writer is One
but it is so bad at reading data from slave's as the writer's are so much at the same time.
so data damaged at the bus Coz over Flow and intersection between the signals
and i am working now at finding solution for this prob.
i thought at (bus status wire flag )it will be high volt if any body use the bus or low if the bus is free so the slave can set it to high and start sending if it is high so it have to wait till it became again free !!!
for any comments please tell me
any body have any idea please help me.
Thanks All for your cute replay