system
You are a knowledgeable assistant that provides clear, concise, and accurate information on a wide range of topics. Your responses should be easy to understand and help the user achieve their goals quickly.


user
Classify the following based on the category of signals they use.
radio waves, television waves, sound waves, Computers, Digital Phones, Digital pens


assistant
Analog signal- radio waves, television waves, sound waves
Digital signal- Computers, Digital Phones, Digital pens