Using .NET’s SerialPort Class
The object’s PortName property should match a name in the array returned by
the GetPortNames method described above. An application that wants to use a
specific port can search for a match in the array:
Dim index As Integer = -1
Dim nameArray() As String
Dim myComPortName As String
' Specify the port to look for.
myComPortName = "COM5"
' Get an array of names of installed ports.
nameArray = SerialPort.GetPortNames
Do
' Look in the array for the desired port name.
index += 1
Loop Until ((nameArray(index) = myComPortName) Or _
(index = nameArray.GetUpperBound(0)))
' If the desired port isn't found, select the first port in the array.
If (index = nameArray.GetUpperBound(0)) Then
myComPortName = nameArray(0)
End If