A standard telephone keypad, with four rows of three keys each. The top row consists of 1, 2, and 3, with keys continuing down in order until the last row, which is usually *, 0, and #. Such a keypad ...

Keypad phones, believe it or not, are still in use, and there is a surprising amount of variety to choose from. Some of the phones include 4G connectivity, cameras, and are built to last. If you're ...

The PCB must be mounted floated, otherwise key presses don't work reliable. Connect pins 3 and 4 on connector P1 for 16-pin button mode. Smaller keypads with less pins may work, but are not tested.