Modems and networks

Modem is a term we are likely to forget soon in the digital age, but for most of us modems were where internetworking began. Modem is short for modulate-demodulate - that's where it got its name. Modems enable the digital form of matter that a computer uses to communicate by the analogue form of transmission of old style telephone systems.

There were apparently some early modems used by the US Air Force in the 1950's, but the first commercial ones were made a decade later. The earliest modems were 75 bps (or bits per second). That's about 1/750th of the speed of current modems, so they were pretty slow! But to early networking enthusiasts, modems were 300 bps. Then came 1200, and by 1989 2400 bps modems.

By 1994, domestic modems had got to 28.8 kilobits per second - which was just as well, because by then we were beginning to send more than text messages over the Internet. This was thought to be an upper limit for phone line transmissions. But along came the 56k modem, and a new set of standards, so the speeds continue to push the envelope of the capacity of the telephone system.

So much so that many of have moved on, into wireless networks, and into "broadband" systems, which allow much faster speeds. But modems made the first critical link between computers and telephones, and began the age of internetworking.

Another of the former Arpanet contractors, Robert Metcalfe, was responsible for the development of Ethernet, which drives most local area networks.

Ethernet essentially made a version of the packet switching and Internet protocols which were being developed for Arpanet available to cabled networks. After a stint at the innovative Xerox Palo Alto laboratories, Metcalfe founded a company called 3-Com which released products for networking mainframes and mini computers in 1981, and personal computers in 1982.

With these developments in place, tools were readily available to connect both old and new style computers, via wireless, cable, and telephone networks. As the networks grew, other companies such as Novell and CISCO began to develop more complex networking hubs, bridges, routers and other equipment. By the mid 1980's, everything that was needed for an explosion of internetworking was in place.