This document discusses different types of communication flows within an organization. It identifies downward communication as flowing from high-level to low-level authorities, such as from general managers to project managers. Upward communication flows from low-level to high-level authorities, like from supervisors to senior engineers. Horizontal communication occurs between peers of the same level, for example between project managers of different departments. Diagonal communication crosses departments from different levels, while external communication is between an organization and outside parties. The document provides an organizational chart to illustrate examples of each type of communication flow.