$FrameNum = substr($ResultUnpacked, 6,2);
$FrameHex = '0x' . $FrameNum;
$FrameNum = eval $FrameHex;

##</code><code>##

$FrameNum = hex substr($ResultUnpacked, 6,2);

##</code><code>##

my $Ack = pack( 'C*', 0xaa, 0x0e, 0x0d, $FrameNum, 0x00, 0x00);

##</code><code>##

my $Ack = pack( 'C*', 0xaa, 0x0e, 0x0d, 0x.$FrameNum, 0x00, 0x00);