A few debugging ideas:

  1. $PortObj->error_msg(1);
$PortObj->user_msg(1);

    [download]
  2. Check for error messages from the module, e.g. ... or die "Error: $^E";
  3. my $count_out = $PortObj->write($output_string);
warn "write failed\n" unless $count_out);
warn "write incomplete\n" if $count_out != length($output_string);

    [download]
  4. Check if you need to set up any flow control, if not, use $PortObj->handshake("none");
  5. Make sure you're setting the CTS, DTR, etc. lines appropriately, if they are connected and being used in hardware.

In reply to Re: can't write-Win32::SerialPort by Anonymous Monk
in thread can't write-Win32::SerialPort by franko

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