Как правильно настроить СОМ-порт?

Private Sub CommandButton4_Click()  'Отправить фрейм
    'Dpribor1 = 0
    Call TxRx(2, 3, 0, 1, 0, 1)                          'Отправить команду
End Sub
 
Sub TxRx(ByRef Nport As Integer, ByRef Func As Integer, _
         ByRef Data1 As String, ByRef Data2 As String, ByRef Data3 As String, ByRef Data4 As String)
'функция отправляет устройству Modbus дейтаграмму
    Dim Frame As String                         ' формируемое сообщение на отправку
    Dim RetBytes As Long, LenVal As Long
'    Dim RxFrame As String                    ' принимаемое сообщение из порта RS485
    
    Frame = Chr(Nport) & Chr(Func) & Chr(Data1) & Chr(Data2) & Chr(Data3) & Chr(Data4)
    Frame = Frame & CRC_16(Frame)
'    If Len(Frame) > 255 Then
'       WriteCOM32 Left$(Frame, 255)
'      WriteCOM32 Right$(Frame, Len(Frame) - 255)
'       Exit Function
'    End If
    
    On Error GoTo handelwritelpt
    For LenVal = 0 To Len(Frame) - 1
        bRead(LenVal) = Asc(Mid$(Frame, LenVal + 1, 1))
    Next LenVal
 
    retval = WriteFile(ComNum, bRead(0), Len(Frame), RetBytes, ByVal CLng(0))
    If retval = False Then
        MsgBox ("Write port ERROR:" & GetLastError)
    Else
        MsgBox ("Data write: Ok")
    End If
handelwritelpt:
    Exit Sub
End Sub

    ReDim b(5) As Byte
    b(0) = Nport: b(1) = Func: b(2) = Data1: b(3) = Data2: b(4) = Data3: b(5) = Data4
    Frame = b

Set mcom = CreateObject("MSCommLib.MSComm")

.....
Public rc As Long
Public h As Long  'Хэндл порта.
Public d As DCB   'The DCB structure and the SetCommState() function allow to set the baud rate and
                  the byte size of theбserial port.
................
Public Sub Sending()
    ' Sending an array of 3 bytes to a remote device.
 
    Dim bWrite(1 To 3) As Byte
    bWrite(1) = &HA1
    bWrite(2) = &HB2
    bWrite(3) = &HC3
    Dim wr As Long
    rc = WriteFile(h, bWrite(1), 3, wr, 0) ' The wr indicates how many bytes were went to the port.
    If rc = 0 Then
      rc = Err.LastDllError
      MsgBox "WriteFile failed, the error code is " & Str(rc)
      GoTo close_and_exit
    End If
close_and_exit:
    rc = CloseHandle(h)
End Sub

12    MSComm1.PortOpen = True
13    MSComm1.Output = Frame