if ($data =~ /(?<![\w-])ON(?![\w-])/i) {

$btn1->configure(-background => "gray", -foreground => "black"); 
$btn1->configure(-state => "disabled");                    

print "ON\n";
}	

if ($data =~ /(?<![\w-])OFF(?![\w-])/i) {

$btn1->configure(-background => "green", -foreground => "black");
$btn1->configure(-state => "normal");                             

print "OFF\n";
}