How does the LCD distinguish data from instruction codes when receiving information at its data pin?

The LCD distinguishes between data and instruction codes by using a control pin, typically called the RS (Register Select) pin. When the RS pin is set to a specific state (usually high), the data pin is interpreted as data to be displayed; when it is low, the pin is interpreted as an instruction code. This allows the LCD controller to determine the context of the information being sent and process it accordingly.