Not a helpful description :-)

Actually, in this specific case it most likely is. Win32::SerialPort is strange in how it works in the Background. The Linux/Unix version (Device::SerialPort) seems to just work by setting some parameters (baud rate etc) and you can get immediately to sending/receiving data.

But in Win32::SerialPort, you have to call write_settings() after configuration changes, otherwise the object will just sit there ignoring all your send/receive calls, most likely without showing a warning or raising an error.