Evolution of the voice networks: Historic perspective from a developing nation

The voice networks have evolved drastically since its invention toward the ending of the 19th century. It evolved from the manual exchange to electromechanical automatic exchanges. It further evolved to analogue electronic exchanges and now to digital exchanges. Voice is very sensitive to delays and delay jitters, and that implies that its associated networks have to be connection oriented and therefore circuit switched. Today, voice services have even evolved from fixed to mobile services and could now be transported via connectionless networks. This paper reviews the various voice networks evolution. Nigeria is used as a case study. This paper also gives relevant evolutionary architectural design of some of the voice networks.