Public Function ComPortExists(ByVal ComPort As Integer) _
As Boolean

Dim udtComConfig As COMMCONFIG
Dim lUDTSize As Long
Dim lRet As Long

lUDTSize = LenB(udtComConfig)
lRet = GetDefaultCommConfig("COM" + Trim(Str(ComPort)) + _
Chr(0), udtComConfig, lUDTSize)
ComPortExists = lRet <> 0
End Function