Using the serial port - vb.net

Question

For some time I've been working on learning how to program VB.NET. With the help of this page and the internet, I managed to create a program that sends some hex values to an interface box and get a routine response from it.
The problem here is that the communication was TCP/IP. But now I have a new box with a USB interface and now I do not have the slightest idea of how to send and receive those same hex values using the Serial port.
Below is the code. I don't know if someone could help me set it up for a serial port named COM13 or at least explain to me what to do.
This is what the program does.
Push scan
Connects to the TCP/IP of the BOX (10.2.12.65)
Sends the activation protocol E1 33
Sends the get date command 05 6c 29 f1 3c 81
Box responds back date with bytes
When the program reads the byte corresponding to 81(hex) it starts converting them into characters and adding them to a string to be displayed on the textbox on the bottom.
That's basically it. The problem is that until now I have been able to send only text strings but the box does not recognize it and it responds garbage and not the date.
Here is the code:
Imports System.Net.Sockets
Imports System.Threading
Imports System.IO
Public Class Form1
Dim client As New TcpClient
Dim transmit As NetworkStream
Dim protocol As Byte()
Dim data As Byte()
Dim ByteArrayToHexStr As String = String.Empty
Dim message As String
Dim datos_byte As Byte()
Dim respuesta As [String] = [String].Empty
Dim transision As [String] = [String].Empty
Dim Date_full As [String] = [String].Empty
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
TextBox1.Clear()
client = New TcpClient("10.2.12.65", 10001)
transmit = client.GetStream()
protocol = {225, 51} ' E1 33 in hex value
transmit.Write(protocol, 0, protocol.Length)
Thread.Sleep(45)
data = {5, 108, 41, 241, 60, 129} ' 05 6c 29 f1 3c 81 in hex value
transmit.Write(data, 0, data.Length)
data = New Byte(66) {}
Thread.Sleep(45)
Dim bytes As Int32 = transmit.Read(data, 0, data.Length)
Dim Date1 As String = String.Empty
Dim Date2 As String = String.Empty
Dim Date_temp As Integer = 0
For i As Integer = 0 To UBound(data)
Date1 = data(i)
If Date1 = "129" Then
Date_temp = i + 1
i = 1000
For k As Integer = 0 To 5
If k = 0 Then
Date1 = data(Date_temp + k)
Date_full = Chr(Date1)
Else
Date1 = data(Date_temp + k)
Date2 = Chr(Date1)
Date_full = Date_full & Date2
End If
Next
Else
End If
Next
Thread.Sleep(45)
transmit.Close()
client.Close()
TextBox1.Text = TextBox1.Text & Date_full
End Sub
End Class

Answer 1

Please have a look at Microsoft's example of the SerialPort class: https://msdn.microsoft.com/en-us/library/system.io.ports.serialport(v=vs.110).aspx?cs-save-lang=1&cs-lang=vb#code-snippet-2
If you get garbage back that might indicate the baudrate is configured incorrectly. I'm not sure what you mean by 'box' but this device should have a specified baudrate which you should be able to find in its datasheet or product information.