How it works: The PFC8574T I2C 8 Bit Adapter with the Vishay 20x4 LCD
Using the I2C 4 line LCD https://www.rhydolabz.com/wiki/?p=16424 There is a section on the I2C LCD Backpack. The PFC8574T I2C to 8 bit IO adapter backpack onto Vishay LCD-020N004L PFD8574 -------------------> 20x4 LCD Header Strip (4) D0 4 Rs H/L Register Select (5) D1 5 R/W H/L Read/write (6) D2 6 E H/L Enable (7) D3 --NC-- (9) D4 11 ...