First, I'm assuming from your use of the Win32::SerialPort module that you're on a Windows box. My first step would be to try using Hyperterminal or putty to manually test issuing the commands and to see what kind of responses that you get back from the device.
This is a fantastic idea and the right way to go. I wish I would have suggested it!

In reply to Re^2: Timing issue while accessing serial port by Marshall
in thread Timing issue while accessing serial port by vrn

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