The Modem

The modulator-demodulator, modem for short, was a revolutionary device that contributed to the popularity of the internet and brought the world into a new era of communication. The first modems were used in 1920 for tele-typing machines, which allowed users to type messages on one end to be received by another machine somewhere else. Around the beginning of the Cold War, the US Air Force turned to the modem in order to efficiently transmit radar images to command centers.

For many, the modem was where internetworking began. The communication would start at one computer, which has digital data that needs to be sent. The modem would encode that digital information and convert it to analogue information. This would be sent through telephone systems to another computer, which had another modem that would do the reverse. The first commercial modem, called the Bell 103, was created by AT&T and became available in 1962. It allowed for data speeds of up to 300 bits per second, compared to today's average Starbuck wifi speed, approximately 25'000'000 bits per second. As the years progressed, modem speeds rapidly increased, pushing the boundaries of phone line transmission that were previously thought to be impossible.

Today's internet employs many concepts from the modems of a few decades ago, except they use signals way past audible frequencies. Without these initial devices, many of todays internet and communicative capabilities would not have been possible.

Sources:
http://www.computinghistory.org.uk/det/6986/The-first-commercial-Modem-manufactured/