The buttons are setup in a matrix format. This allows a microcontroller to 'scan' the 7 output pins to see which of the 12 buttons is being pressed.

Check the examples below for correct pin-outs and such.

Useful links:

• PIC HEX Pad Tutorial
• Arduino Instructable
• Arduino Keypad Library
• Alarm System Project
• Key Pad Example
• Bildr Example

• [Data Sheet]: Keypad - 12 Button Datasheet
• [Sample Code]: Sample code for 50847 Keypad