Arduino not responding via serial communication

Using Arduino Programming Questions
14

deepu1994:
As per my esc , it needs minimum throttle for at least a second.... so when i send the lowest throttle it arms which noted as esc_calib();

But you show a

//esc_calib();

in your setup function, so you are not performing the function?

i have a plenty of memory IDE shows
Binary sketch size: 11,878 bytes (of a 32,256 byte maximum)

....