What is the fundamental difference between digital and analog data?

The fundamental distinction between digital and analog lies in how they represent information. Analog signals are continuously variable, meaning they represent data using a smooth, unbroken range of values over time, much like a sweeping curve. Conversely, digital data is encoded as discrete, pre-agreed values—typically binary ones and zeros. Instead of flowing continuously through an infinite number of values, a digital signal jumps abruptly between specific defined states. Because digital data uses these distinct steps, it is highly resistant to noise; the receiving equipment only has to decide which of the pre-agreed discrete states a signal is in, rather than interpreting an exact continuous voltage.