>perl -wMstrict -le
"my $SM      = 0xfe;
 my @ADRDSTN = (0x00, 0x09, 0x01, 0x00);
 my $MID     = 0x01;
 my $MDLH    = 0x00;
 my $MDLL    = 0x18;
 my $EM      = 0xFD;
 ;;
 my @message = (@ADRDSTN, $MID, $MDLH, $MDLL);
 ;;
 my $packed_message = pack 'C*', @message;
 ;;
 my $checksum = 256 - unpack '%8C*', $packed_message;
 ;;
 my $msg_for_socket = pack 'C a* C C', $SM, $packed_message, $checksum, $EM;
 ;;
 my $msg_for_debug = unpack 'H*', $msg_for_socket;
 print qq{'$msg_for_debug'};
"
'fe00090100010018ddfd'