Lemelson-MIT Program
Who We Are Awards Outreach News
Invention Dimension Search Site Map Contact Us
Inventor of the Week

Inventor of the Week Archive

Browse for a different Invention or Inventor


56K Modem

Canadian inventor and electrical engineer Brent Townshend created a core concept in 1996 that served as the basis for what is known as the 56K bit/sec modem, a groundbreaking and critical appliance that for the first time allowed for data transfer between two computers at high speeds.

Born in 1960, Townshend earned a PhD in electrical engineering from Stanford University in 1987 with expertise in signal processing, computer system design, and statistical modeling. He worked as a principal investigator for Bell Labs from 1987 to 1990 where he studied speech recognition and low-bit-rate speech encoding. The Toronto native then moved to Montreal where he established Townshend Computer Tools and developed Dat Link, a signal processor for making high-quality audio recordings.

In 1993 he moved Townshend Computer Tools to Menlo Park, Calif., and began working on MusicFax, an appliance for downloading music from servers via direct-dial telephone connections. It was while working on this project that he came up with his idea for a better modem (which stands for modulate/demodulate), in an attempt to solve the problem of getting high-speed data from a digital server to multiple analog destinations.

Digital modems had been developed earlier, in the 1950s, for the purpose of transmitting data for the military. They were used to send data over the PSTN, or public switched telephone network. The first commercial modem was manufactured by AT&T in 1962, with a speed of 300 bits per second. By 1993, modems were performing at around 38.6 Kbps. Townshend developed an algorithm that enabled 56K downloads from the Internet over standard analog dial-up phone line connections. This represented a 66 percent improvement over previously existing modems' performance. His technology allowed for this to occur only in the download direction, which eliminated cumbersome analog-to-digital conversions and kept speed consistent. This concept also happened to serve the needs of the typical ISP-computer user relationship sufficiently. With his innovative creation, he beat many others to the punch who had been working on similar devices.

Townshend received U.S. Patent No. 5,801,695 in 1994 for pulse-code modulated, or PCM-based client modems. He received four additional patents for related technology as well. He approached U.S. Robotics with his concepts and later, 3Com Corp., which acquired U.S. Robotics, negotiated exclusive rights to his patents. However, a number of companies allegedly began using technology credited to Townshend without licenses for doing so, and he was subsequently embroiled in several high-profile legal battles, most notably with Analog Devices, Cisco Systems, Intel, ESS Technology, and Agere Systems.

Most of these have since been settled, and Townshend is said to have made a substantial fortune in licensing fees since 56K modems hit the worldwide market in 1997. In 1998, the V.90 standard that incorporates Townshend's algorithm was ratified by the International Telecommunications Union. That standard was later updated as the V.92 standard.

Townshend served as a Consulting Professor of Electrical Engineering at Stanford University and in 1997, joined Menlo Park, Calif.-based Ordinate, a speech-assessment software company, as CEO. The company's PhonePass product is used to evaluate how well non-native English speakers have learned to speak the language. Ordinate was later acquired by Harcourt Assessment, a division of Reed Elsevier's Harcourt Education company. Townshend continues to serve on its advisory board and to operate Townshend Computer Tools, LLC.

Invention Dimension
Inventor of the Week Inventor of the Week
Inventor's Handbook Inventor's Handbook
Games & Trivia Games & Trivia
Links & Resources Links & Resources