Samsung Galaxy Pocket Duos unlocking screen in horizontal position when calling I noticed this function on Alcatel with same version of Android (2.3.6). When you talking phone blocked, but when you changing phone to horizontal position(standart position for working with phone) it unlocks screen.

This function is very helpful if you need to finish call fast.

is ti posible to add this function to my Samsung Galaxy Pocket Duos?
It's not normally to do with the position of the phone, there's normally a "proximity sensor" on the front of the phone that locks the screen if the phone is against your face, and unlocks the screen a few moments after you take it away from your face.

According to the Galaxy Pocket Duos's specs on GSM Arena there's no proximity sensor built into that model, compare with the Alcatel OT-991 or Samsung Galaxy S's specs where you can see they do have a proximity sensor.