The process by which information is exchanged through a common system of symbols, speech, signs, machines, and behaviors, interchange of thoughts, opinions, or information by speech, writing, or signs. Methods of communication include wave communications, telecommunications, and graphic communications. Different modes of transmitting messages include person to person, person to machine, machine to person, and machine to machine. Graphic communication techniques like drafting, freehand sketching, and various printing processes are also discussed.