Godra, That's a good idea.
Here is the code I am using.
Private Sub ReadCom(ByVal ReceiveSerialData() As String)
' Receive strings from a serial port.
Dim returnStr As String = ""
Dim com1 As IO.Ports.SerialPort
' Change this string for the port number
com1 = My.Computer.Ports.OpenSerialPort("COM27")
com1.ReadTimeout = 10000
com1.Open()
Dim Incoming As String = com1.ReadLine()
returnStr &= Incoming '& vbCrLf
If com1 IsNot Nothing Then TextBox1.Text = returnStr
End Sub