This document classifies and describes different channels of communication. It discusses visual channels like facial expressions and written words, auditory channels like spoken words and phone calls, and tactile channels like touch. It also mentions combined channels that use both audio and visual media. The document goes on to define receivers as those who receive, decode, and interpret messages, and feedback as return messages sent by receivers to senders to complete the communication process. It concludes by explaining confounding elements like interpersonal variables and environmental factors that can indirectly influence communication.