Sending a voltage to RS232

Question

I know that we can use pin no.3 to send the data as a output in RS232. But I am just wondering that there is another way to send only the voltage 5v to the RS232 in a short

Answer 1

You could use the DTREnable (Data Terminal Ready) property of the SerialPort class to apply a positive voltage to those respective pins. This could be used to signal an MCU.

Something along the lines of...

serialPort.DtrEnable = true; //High
currentThread.Sleep(1000);
serialPort.DtrEnable = false; //Low
currentThread.Sleep(1000);

However! the voltage is likely to be incompatible as RS232 operates -25 to 25 volts for 1/0's. You will likely need an inline driver/receiver such as a MAX232 chip to operate between the MCU and computer, or dependant on your skill level you could build a receiver circuit.