Well, I figured it out! Since I am using an Arduino Mega with 4 serial ports so what's the problem? All Slaves and Controllers use RJ-45 connectors and ethernet cable.

There is very little magic here as Arduino has built-in drivers for the serial ports. I stay away from the serial port 0 has that has the USB on it which is good for loading and debugging. The only thing you have to be careful with is that TX is always wired to RX.  So, to sum up, this table below:

  • All wire cat5 cabling is straight wired. And has NO TWIST!
  • All Arduino(s) are wired the same
    PinsColorsSignal
    1Orange-WhiteAtx
    2OrangeBtx
    3Green-White
    4Blue
    5Blue-White
    6Green
    7BrownAtx
    8Brown-WhiteBox

     

    • Tx -> Ro (module #1)
    • Rx -> Di (module #2)
  • the outputs of the module has the twist! (Remember that since this is Full-Duplex that two twists are needed.
    • The Controller's module is Normal that is NO TWIST!!!
    • Ths Slaves have a twist after the jack.
      • Slaves Receivers are connected to the transmitter side on the Controller.
      • Slaves Transmitters are connected to the side of the receiver of the Controller.

Since RS-485 needs to know what unit id the slave is, each Controller and Slave has a four(4)position dip switch. This gives you 16 address, with 0 reserved for the controller.

When using TA-56B wiring

 

PinsArea Controler (ser 1)Slave 1 (ser 1)Slave 2 (ser 1)Slave 3 (ser 1)Slave 3 (ser 1)
D18 tx(1) RO Module TTL to RS-485 (1) RO Module TTL to RS-485 (1) RO Module TTL to RS-485 (1) RO Module TTL to RS-485 (1) RO Module TTL to RS-485
D19 rx(2) DI Module TTL to RS-485 (2) DI Module TTL to RS-485 (2) DI Module TTL to RS-485 (2) DI Module TTL to RS-485 (2) DI Module TTL to RS-485
A(1) RO Module TTL to RS-485
B(2) DI Module TTL to RS-485
A(1) RO Module TTL to RS-485 (1) RO Module TTL to RS-485 (1) RO Module TTL to RS-485 (1) RO Module TTL to RS-485
B(2) DI Module TTL to RS-485 (2) DI Module TTL to RS-485 (2) DI Module TTL to RS-485 (2) DI Module TTL to RS-485