iTunes has detected an iPhone in recovery mode

My iPhone has a black

screen. When I connect iPhone to iTunes, iTunes recognizes iPhone and reports "iTunes has detected an iPhone in recovery mode. You must

restore this iPhone before it can be used with iTunes." It also does

not recognize serial number (Serial Number: n / a). After trying to

restore, briefly about 5 seconds, Apple logo appears on iPhone and iTunes then

reported the error "The iPhone" to iPhone "could not be restored. An unknown

error occurred (4014)". After this, again the screen is black.

[Re-Titled by Moderator]