Visual Basic - como abrir cajón portamonedas con Epsom TM-M88IV

Public Structure SECURITY_ATTRIBUTES

        Private nLength As Integer

        Private lpSecurityDescriptor As Integer

        Private bInheritHandle As Integer

    End Structure

    Public Const GENERIC_WRITE = &H40000000

    Public Const OPEN_EXISTING = 3

    Public Const FILE_SHARE_WRITE = &H2

    Dim SA As SECURITY_ATTRIBUTES

    Dim outFile As FileStream

    Dim Safe As Microsoft.Win32.SafeHandles.SafeFileHandle

    Public LPTPORT As String

    Dim hPort As Integer

    Dim hPortP As IntPtr

    Dim retval As Integer

    Public Declare Function CreateFile Lib "kernel32" Alias "CreateFileA" (ByVal lpFileName As String, ByVal dwDesiredAccess As Integer, ByVal dwShareMode As Integer, ByRef lpSecurityAttributes As SECURITY_ATTRIBUTES, ByVal dwCreationDisposition As Integer, ByVal dwFlagsAndAttributes As Integer, ByVal hTemplateFile As Integer) As Integer

    Public Declare Function CloseHandle Lib "kernel32" Alias "CloseHandle" (ByVal hObject As Integer) As Integer

hPort = CreateFile(COM1, GENERIC_WRITE, FILE_SHARE_WRITE, SA, OPEN_EXISTING, 0, 0)

                        hPortP = New IntPtr(hPort) 'Convierte Integer to IntPtr

                        Safe = New Microsoft.Win32.SafeHandles.SafeFileHandle(hPortP, True)

                        If Not Safe.IsInvalid Then

                            outFile = New System.IO.FileStream(Safe, IO.FileAccess.Write)

                            fw = New System.IO.StreamWriter(outFile)

                            fw.AutoFlush = True

                            fw.WriteLine(cadena)

                            fw.Close()

                        End If

                        CloseHandle(hPort)