I suggest that if possible never disconnect the USB cable, but instead connect/disconnect the serial cable and use the state of handshake lines or the cessation/resumption of data flow to indicate the connect/disconnect. You are stymied if the 'serial port' is internal to a hardware device however and you can't break the serial connection.

Maybe you need to tell us a little more about the bigger picture for better advice? In particular, why are devices connected and disconnected and what sort of device are thy?

True laziness is hard work

In reply to Re^3: Win32::SerialPort ; close / open problem by GrandFather
in thread Win32::SerialPort ; close / open problem by philipMac

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