What is the number layer of TTL?

TTL, or Transistor-Transistor Logic, typically refers to a logic family that can be categorized into multiple layers based on its complexity. While there isn't a universally defined "number layer" for TTL, it is commonly understood to operate at the first two layers of abstraction: the physical layer (transistors and gates) and the logical layer (basic logic functions like AND, OR, NOT). Advanced implementations may involve higher levels of integration and sophistication, but the foundational aspects of TTL primarily concern these initial layers.