RS422 Connection as Simplex: It transmits-receives data in only one direction; its direction of communication is fixed either to
be receiver or transmitter only. When connecting signal in this way, it requires a pair of Cable (2-Wire). There is an advantage
of this connection type because it uses only one Circuit Transmitter but it can connect to 256 positions on the side of Circuit
Receiver; moreover, it uses a pair of Cable only.
Picture shows how to connect Cable RS422 as Simplex.
Picture shows how to connect Cable RS422 when receiving data from many devices simultaneously.
HOW TO CONNECT SIGNAL AS RS485
Connect whole system as Parallel: When connecting device in this way, it has to set priority of devices that are connected
together in the system. A device must be set as Master device, it will be an intermediate for transmitting-receiving all data, or it
may set order of transmitting-receiving data to other devices. For Slave devices, it must be set to receive data all the time first.
Master device scans each Slave device carefully to check if there is any data for transmitting; if yes, the Master device will
check where the destination is and it commands the specific device to receive the data directly. Next, the direction of Master
device will be changed to be receiver instead in order to set the Cable free (floated) and both devices is allowed to transmit
data. After both sides transmitted data completely, the Slave device must send Command to notify the Master device to know
that the transmission is complete and the Master device will scan the next Slave device.
