What is Pulse code modulation Principles? | What is PCM Principles? Pulse code modulation Principles | PCM Principles 1.1 A long distance or local telephone conversation between two persons could be provided by using a pair of open wire lines or underground cable as early as early as mid of 19th century. However, due to fast industrial development and increased telephone … [Read more...] about Pulse code modulation Principles | PCM Principles