Hi, you can connect an Arduino-style keypad (8 pins) to an Industruino PROTO, as it provides direct access to the GPIO pins.
For interaction with an Industruino INDIO i would suggest to use the RS485 port, for example with a Nextion touchscreen as documented at https://industruino.com/blog/our-news-1/post/nextion-hmi-with-industruino-42 or you could get an off the shelf RS485 keypad. RS485 will allow you to use a longer cable length.
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