Does MAX485 (RS485) requires 3rd wire as GND

[camsysca]

See message 12, this thread:

Arduino Uno, Max 485 simplex communication [solved]

Hi guys, the program compiles but it doesn´t do anything, when i push the button the master should send the letter E and the slave should turn the led on, and when the push button is not pressed and the master should be sending the letter A and the led in the slave should be off. Master // C++ code // const int boton1 = 10; int estadoboton = 0; void setup() { Serial.begin(4800, SERIAL_8E1); pinMode(10, INPUT_PULLUP); } void loop() { estadoboton = digitalRead(boton1)…

There are many, many guides out there on the web to choose from, but the best is to go to the designers, I think.