SerialExample.cs

using GHIElectronics.TinyCLR.Devices.SerialCommunication;
using GHIElectronics.TinyCLR.Pins;
using GHIElectronics.TinyCLR.Storage.Streams;
using System.Threading;

namespace SerialExample {
    class Program {
        static void Main() {
            var ser = SerialDevice.FromId(FEZPandaIII.SerialPort.Com1);
            ser.BaudRate = 9600;
            ser.StopBits = SerialStopBitCount.One;
            ser.Parity = SerialParity.None;
            ser.DataBits = 8;
            ser.Handshake = SerialHandshake.None;

            var reader = new DataReader(ser.InputStream);
            var writer = new DataWriter(ser.OutputStream);

            writer.WriteString("Ready\r\n");
            writer.Store();

            while (true) {
                var read = reader.Load(10);

                if (read > 0) {
                    var str = reader.ReadString(read);

                    writer.WriteString(str);
                    writer.Store();
                }

                Thread.Sleep(10);
            }
        }
    }
}