"\x30" is "0". This would seem to indicate you've made an incorrect assumption as to what read returns. Checking the docs confirms this. 

($count_in, $string_in) = $PortObj->read($InBytes);
warn "read unsuccessful\n" unless ($count_in == $InBytes);

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In reply to Re: Getting started - serial, bytes and hex output by ikegami
in thread Getting started - serial, bytes and hex output by JimLS

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