VoIP: Not Your Father’s Telephone Service (chapter 2)

Voice  over  IP represents a significant change from the  traditional way that telephone calls have  been handled until recently. Even so, the genesis
of VoIP is rooted in the  history of networks, specifically, the  history of the  circuit-switched phone network.

This chapter explores just  a bit of that history. It offers a whirlwind tour of how phone systems got to where they  are today and  how that relates to VoIP. By understanding the  way that phone networks relate to things such as regu- lated phone costs, you’ll find it easier to grasp the  huge cost savings that can be realized by converting to VoIP.

oice  over  IP represents a significant change from the  traditional way that telephone calls have  been handled until recently. Even so, the genesis
of VoIP is rooted in the  history of networks, specifically, the  history of the  circuit-switched phone network.

This chapter explores just  a bit of that history. It offers a whirlwind tour of how phone systems got to where they  are today and  how that relates to VoIP. By understanding the  way that phone networks relate to things such as regu- lated phone costs, you’ll find it easier to grasp the  huge cost savings that can be realized by converting to VoIP.
could be carried electronically over a pair of wires. He also demonstrated that the  endpoints for these wires  had  to be connected to the  right equipment — hardware that he invented. Mr. Bell’s inventions ushered in an age of commu-  nication that made the  world much smaller than it had ever  been before.

When Mr. Bell invented the  telephone and  thereby gave birth to the  tele- phone network, VoIP was not  even  a consideration. (Truth be told,  the idea of a network wasn’t  yet a consideration either.) Other inventions would  be required before VoIP could become a reality.

The first telephone equipment was analog. Historians and  technicians alike have  labeled the  first phone service POTS, or plain old telephone service. VoIP won’t function very well over  a POTS system; it requires a digital  network.

Digital networking for telephones was invented in the  1920s, but  the  first digi- tal networks would  not  leave  the  laboratory until much later,  in 1964. Today,  most phone companies in the  United  States have  updated their equipment to include digital  service.

Over time,  the  POTS network gave way to the  PSTN, or public switched tele- phone  network. (The  terms PSTN, public switched telephone network, public telephone network, and  phone network are used synonymously.)

Although it occurred in what  seems like the  ancient past, Alexander Graham Bell’s work is important in understanding VoIP. The POTS network that began with his invention has  grown  into the  largest circuit-switched network in the  world. It also  has  become an expensive network, with individuals and  compa- nies  spending hundreds of billions of dollars each year  for communication services.

VoIP, which  was developed in 1995, is gradually replacing the PSTN. Some view the PSTN as the antithesis of VoIP, but it still remains the standard of quality by which  VoIP is measured. For instance, people often ask whether VoIP pro- vides voice quality  as good as what is delivered through the PSTN. Most of the  factors used to evaluate the quality  of VoIP are based in some way on the PSTN, so understanding a bit about the older  networks is important.