DS9105,pdf datasheet (iButton

Unlike conventional keypads, where data is entered by pressing a mechanical key, the solid buttons of an iButton keypad allow users to enter data by simply touching each button with an iButton probe or handheld computer. Each of these buttons comes from the factory with blank memory, allowing the user to program each button with whatever data the user would like entered when touched. The iButton
keypad is a simple, robust alternative for data entry in harsh environments such as outdoors, industrial
workplaces and other locations, where a normal keypad is impractical to operate. Since iButtons are made
from stainless steel, this keypad is easily cleaned with hot water and detergent.
The individual iButtons that comprise the keypad can be arranged as desired to maximize ease of use.They can be stuck on a smooth surface using adhesive pads or mounted through 16.5mm holes in a rigid material and fastened by lock rings. The material thickness should not exceed 3.0mm. For a detailed description of the communication protocol and the electrical characteristics of the iButton used in this keypad, refer to the DS1982 data sheet.