 It is the TCA8418 keypad matrix driver and GPIO expander. Here's an example of using it with telephone style keypads. I decided to solder the board four columns and two of the row pins, and then the extra two I have running since they're on the other side of the board using wires there. But that gives you this sort of neat little keypad that you can use for different projects. I have it plugged in over I squared C into this is our Trinkie. I plug that into a USB hub so we can imagine that's the side of your laptop or some other computer that you want to plug into. Now I have immediate access to this cute little keypad. So here I'm just going to put in a comment there and then you can see I can get one, two, three, A, four, five, six, B, seven, eight, nine, C, star, zero, pound, D. It is the TCA8418 keypad matrix and GPIO breakout.