1.I'm using ordinary CAT-5 or RJ45(10BaseT) connectors.
The connector of ethernet was Tx-&Tx+ and RX- and RX+.
That's as same as RS-485 without modification cables,just replace from broken card LAN(with RJ-45) and connected pin 1 & 2 to A B of RS-485 and pin 3&6 to X Y of RS-485 or vice versa.

2.How's it works:
Suppose there was 16 slave and 1 master(all MCU,master MCU more speed and programmable uart)
4 wire.

Master sent routing(with address(ID) to get data from slave 1 to 16

Master --at A and B(cables)-->slave(1)
Master---at A and B(cables)-->slave(2)
........
Master---at A and B(cables)--->slave(16)

at the same time
Master --at X and Y(cables) get response from

<---Slave(1)
....
<---Slave(16)

This mean the Master was full duplex and slave(waiting their command response from Master)


Is there someone had .code to doing full duplex(.asm or .C).
clients(MCS-51s) code.