Raspberry Pi connectivity compatible with Raspberry Pi Zero/Zero W/Zero WH/2B/3B/3B+ ^^ Onboard SC16IS752 expands 2-ch UART and 8 programmable GPIO through I2C no extra pin required ^^ It is stackable up to 16 this modules by setting the address jumper that means up to 32-ch UART ^^ Onboard multi LEDs for indicating the UART working status ^^ Reserved I2C control pins allows to work with other control boards