Windows Plug and Play (PnP) - for general purpose USB to RS232 serial converters it is desirable that the device tries to recognise any attached secondary peripheral that conforms to the Windows Plug and Play standard. These devices are typically modems, or serial mice. On recognition of such a device Windows will attempt to identify and load the drivers for the secondary peripheral. For other application areas PNP is not usually required so this option should be turned off.