Hello Jakub, I just got hold on a Cis Lunar MK-5P unit and I am attempting to understand how it works. I need your help. I read a pin code was needed for the unit. But I did not get any with unit. So far the dive computer is switching on and display properly different information (tank pressure, depth, beeping ...). At that stage I have not been asked any pin code. Can you let me know when the pin entry screen is prompted ? Is a pin code compulsory to make the machine work ? If required, is there anyway to reset it ? My objective is to understand the machine. I do not think I will dive it. Just impressed by the complexity and "smartness" of the machine. Kind Regards, Nicolas di Costanzo