Standard Modem Technology Proved Capable of Extraordinary Improvement

• Back in the early days of networking--in the 1960s and 1970s--it was thought that high-speed data communications would require special data-friendly phone lines: ISDN or some similar service.
  
• It was expected that "ordinary" phone lines used for POTS would be capable of carrying data transmissions at the 103 standard 300 bits per second, or perhaps at most the V.22bis standard 2400 bits per second, but no faster.
  
• Yet over the past two decades we have seen a 22-fold increase in the speed of data transmission obtained over ordinary telephone lines.
  
• This extraordinary 18 percent per year improvement in data-transmission-over-POTS is not the pace of Moore's Law, but it is very rapid. It allows everyone with a phone line today the potential to connect at speeds that 20 years ago it was thought would require expensive, dedicated equipment.
  
• This tremendous improvement in standard modems has greatly fueled the growth of the internet. It has allowed the build-out of the world wide data network on top of the already-existing phone network.
  
• It has thus shaved a telephone-equipment generation off of the time it would have otherwise taken to wire the United States for the internet.
  
• And looking forward, at least half the phone lines in the U.S. are suitable for high-speed DSL service. And approximately three-quarters of the households not suitable for DSL service are potential customers for cable modems.

Source: Kim Maxwell (1999), Residential Broadband (New York: Wiley).