How can I read the serial port's input values?

I'm trying to read the input values of port com , in specific COM3 , but it does not work.

I tried the examples provided by the MS page, about the ports, but these simply do not receive data ..

I have tried several codes, and demos, but none seems to receive the data: 1.- link 2.- link

These are some examples, that I have based, and I see that the majority uses the event of SerialDataReceivedEventHandler(port_DataReceived); ....

I have tried emulators, which communicate for example com1 to com2 . and these do work. but already receive the data of com3 , no.

Someone who has handled or resolved this?

Edited

I am connected to a digital scale, which uses the COM3 port The image that I am adding are the parameters that require for the connection in hyperterminal. basically those are manually configured to the "SerialPort" component.

using System;
using System.Collections.Generic;
using System.IO.Ports;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace lectura
{
    class Program
    {
        static void Main(string[] args)
        {
            SerialPort mySerialPort = new SerialPort("COM3");

            mySerialPort.BaudRate = 9600;
            mySerialPort.Parity = Parity.None;
            mySerialPort.StopBits = StopBits.One;
            mySerialPort.DataBits = 8;
            mySerialPort.Handshake = Handshake.None;
            mySerialPort.RtsEnable = true;
            mySerialPort.DtrEnable = true;
            mySerialPort.DataReceived += new SerialDataReceivedEventHandler(DataReceivedHandler);

            mySerialPort.Open();

            /*
            while (true) {
                if (mySerialPort.BytesToRead > 0) {
                    byte b = (byte)mySerialPort.ReadByte();
                    Console.WriteLine(b);
                }
            }*/




            //byte b = (byte)mySerialPort.ReadByte();
            //char c = (char)mySerialPort.ReadChar();
            //string line = mySerialPort.ReadLine();

            //
            //Console.WriteLine("byte "+ b);
            //Console.WriteLine("char " + c);
            //Console.WriteLine("line " + line);
            Console.WriteLine("Press any key to continue...");

            Console.WriteLine();
            Console.ReadKey();
            mySerialPort.Close();
        }
        private static void DataReceivedHandler(
                        object sender,
                        SerialDataReceivedEventArgs e)
        {
            SerialPort sp = (SerialPort)sender;
            string indata = sp.ReadExisting();
            print(indata);
            //Console.WriteLine("Data Received:");
           // Console.Write(indata);
        }

        private static void print(string data) {
            Console.WriteLine(data);
        }
    }
}

and this is the example provided on the ms page about reading the "System.IO.Ports" ports. Greetings