if( value == 'H' ) // if 'H' was received
{
digitalWrite(ledpin, LOW); // turn ON the LED
} else {
You are doing the pin LOW where you want to turn the LED on that's why!
if( value == 'H' ) // if 'H' was received
{
digitalWrite(ledpin, LOW); // turn ON the LED
} else {
You are doing the pin LOW where you want to turn the LED on that's why!