Well I said I only compiled it not that I ran it!  haha!  OK Now I have run it.  You also need to do a serialPort.Open() on the serial port.  So change main to this:

public static void Main(){	// write your code here	SerialPort serialPort = new SerialPort("COM1", 9600, Parity.None, 8, StopBits.One);	serialPort.Open();	byte[] outBuffer = System.Text.Encoding.UTF8.GetBytes("Hello World!rn");	serialPort.Write(outBuffer, 0, outBuffer.Length);            	serialPort.Dispose();            //keeps the emulator running to see results            	Thread.Sleep(Timeout.Infinite);}

which came from running code, and I can see the output from the serial port.

 

And I guess you've stumbled across one of the little joys: you got an ArgumentException, but the arguments (to Write) were fine, it was just the state of the object was unexpected.

Hi all.

I'm using GSMshield Icomsat v1.1 with netduinoplus. I need to communicate with the GSmShield through the serial port. on your post above, I just dont see declaration about netduino digital Pins as Rx/Tx. can anybody explain?

thx

Thank you very much. Very insightful 

Yes I did pretty much get to grips with the SIM900 now. I'm getting round the power-up problem using a relay as mentionedd before. It is very cumbersome, and wastes a GPIO pin, but it will do for now.

 

I also managed to hit the USB power limit finally. Determined to find the limit, I dropped in a shift register with LEDs attached ... once I got to 8 LEDs on the SIM900 wouldn't power on any more 

Hi NightHawk

I do use Icomsat V1.1 and Netduino too...  could you please share the code how to communicate with it. Do you use serial communication on it?

so... do you turn it off and on automatically to safe the power?

cool..... class works fine....

a little bit modif....

Using the class:

            AnalogInput A0 = new AnalogInput(Pins.GPIO_PIN_A0);            ADC.Conversion Temp;                  Temp = new ADC.Conversion(A0.Read());            DataStorage Log = new DataStorage("testFile.csv", "testPath");                                    while (true)            {                                    Temp.analogread(A0.Read());            //Log.ContentFile = Contain.MovingAverage(Temp.miliVolts).ToString("F");            if (Log.Write())            {                Debug.Print( Temp.miliVolts.ToString("F");            }            else { Debug.Print("Write Data Error"); }                        Thread.Sleep(10000);            }