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UART is an Asynchronous transmission device hence there is no clock signal to sync the data between the two devices instead it uses start and stop bits at the start and end of each data packet respectively to mark the extremities of the data being transferred. We tried to build an organic system so that whoever gets a TXtemp, rs485 cable TXsoil sensor or a bridge for RS232 or ModBus sensors and devices like TXdata can immediately use them without wasting time in configurations (and we also took the opportunity to insert some things into our system some "extra" not foreseen by the standards!). On the other hand, RS485 is more industry-based communication which is developed for a network of multiple devices that can be used over long distances and at greater speeds too. Shown below is the example of how a character is a transmitter over a UART data line. After connecting as for point B, in the Settings it is possible to define a name for the device, and if the reading periodicity is less than 250 minutes, you can set an interval of hours in which the reading is not carried out / transmitted (for example you can disable the night).

An example of how a byte(0x3E) is transferred over the two lines of RS485 Communication. They have Shielding Jacket over the insulation layer to protect against the Electromagnetic Interference and also each pair of wires is twisted together to prevent any current loop formation and thus much better protection against the noise. The main reason behind using these Ethernet Cables over normal wires is that they provide much better protection against noise creeping in and distortion of the signal over high distances. There are many different types of serial communication protocols like I2C and SPI which can be easily implemented with Arduino and today we are going to look at another most commonly used protocol called RS485 which is very commonly used in high noise industrial environments to transfer the data over a long distance. We have been using Microcontroller Development Boards like Arduino, Raspberry Pi, NodeMCU, ESP8266, MSP430, etc. for a long time now in our small projects where most of the times distance between the sensors and board is not more than few centimeters at max and at these distances, the communication between the different sensor modules, relays, actuators, and controllers can be easily done over simple jumper wires without us being worried about the signal distortion in the medium and the Electrical noises creeping into it.

Most of the low-cost sensors and other modules like GPS, Bluetooth, RFID, ESP8266, etc. which are commonly used with Arduino, Raspberry Pi in the market uses UART TTL based communication because it only requires 2 wires TX(Transmitter) and RX (Receiver). Previously we have also performed MAX485 communication with Arduino and also MAX485 Communication with Raspberry pi, you can also check them out if interested. 2 Alphanumeric LCD, and MAX485 UART to RS485 converter IC connected to each end of an Ethernet Cat-6E cable via an RJ45 connector. You need a special Ethernet cable for realizing this communication protocol. The resulting signal levels on the interface cable connect the local and remote in a manner specified by a standard protocol. We start with including the standard library for driving the LCD and declare the D8 pin of the Arduino Nano as an output pin which we will later use to declare the MAX485 Module as a transmitter or Receiver. It is not a standard Communication protocol, but it is a physical circuit with which you can transmit and receive serial data with other peripherals. The connection diagram for the above circuit is also given below. The below image shows the transmitter and receiver circuit diagram for Arduino's long-distance wired communication.

The driver is limited for short-circuit current and the driver outputs can be placed at a high impedance state through the thermal shutdown circuit. The receiver input has a fail-safe feature that guarantees logic high output if the input is open circuit. High (mark) parity means that the parity bit is always logic 1 at the UART, and low (space) parity means that the parity bit is always logic 0 at the UART. The RS232 signals are represented by voltage levels with respect to a system common (power / logic ground). The default serial routines used to download programs to the operating system assume that full duplex communications are available, so you cannot use the RS485 protocol to program the controller. Having a second serial port is also handy for system debugging. In other words, each local UART on the wildcard can both send data to and receive data from a remote UART on the other end of a connecting serial cable.