IIC I2C LCD Module For 16×2 And 16×4 LCD is? used to give HD44780-compatible interface LCD modules a serial interface via the I2C bus. This allows you to control the LCD with only two data wires from your microcontroller (and power of course).

Notes:
These modules are currently supplied with a default I2C address of either 0x27 or 0x3F. To determine which version you have check the black I2C adaptor board on the underside of the module. If there a 3 sets of pads labelled A0, A1, & A2 then the default address will be 0x3F. If there are no pads the default address will be 0x27.The module has a contrast adjustment pot on the underside of the display. This may require adjusting for the screen to display text correctly.