## Juggling Genius Claude Shannon Launched the Digital Age

Claude Shannon turned the world on its head by developing Information Theory, which blazed a trail toward digital communication. |

Claude Shannon has been described as the "intellectual giant of the digital age." By the time of his death on Feb. 24, 2001, Shannon had collected a pile of prestigious prizes that proved it — the National Medal of Science, Japan's Kyoto Prize, the IEEE Medal of Honor among them. But, none of those awards quite measured up to the honor he received in October 1998, when AT&T Labs named its two-building, 387,000-square-foot complex in Florham Park, N.J., the Shannon Laboratory.

Perhaps that building's sign should have read "Shnon Lab," because as the Father of Information Theory, Shannon paved the path for digital communications by introducing ingenious concepts for efficiently packaging and transmitting data.

**Birth of the theory**

Considered the Magna Carta of communication, Shannon's Information Theory first
appeared more than 50 years ago in his 1948 *Bell System Technical
Journal* paper "The Mathematical Theory of Communication."

Information Theory describes an ideal communications system in which all information sources -- people speaking, computer keyboards, video cameras -- have a "source rate" measured in bits per second. The channel through which the source's data travels has a "capacity," also measured in bits per second. Information can be transmitted only if the source rate does not exceed the channel's maximum capacity, now known as the Shannon limit.

To approach the Shannon limit, communications engineers encode data, compress it to remove redundancy, and transmit only information essential to understanding. By posting the sign "Shnon Lab," for example, we would eliminate predictable, redundant symbols and send only those symbols that contain unpredictable news -- what Shannon called "information."

It sounds simple, but the complex mathematical formulas embedded in Information Theory have guided the discoveries of two generations of communications engineers. "Information Theory stimulated all kinds of intellectual energy," says AT&T Fellow Neil Sloane, whose research on the mathematical framework of communications is rooted in Information Theory. "Without Shannon's theory, we wouldn't have all the digital devices we depend on today -- wireless phones, fax machines, compact disks or the Internet." Shannon's ideas have even been applied in such diverse fields as psychology, linguistics, economics and biology.

Shannon does the math at Bell Labs, 1955. |

"Because Information Theory was such a profound development, history will remember Shannon as one of the great thinkers in the field of electrical engineering," says AT&T Fellow Larry Greenstein, who relied on Shannon's theories in researching point-to-point radio and wireless communication channels. "He broke the mold in the field of communications and did something unlike anything that came before -- not just an extension or improvement."

**The cycling scholar**

Just as unique as the theory was the theorist himself. Born in 1916, Michigan
native Shannon arrived at AT&T in 1941 after producing what's been called
the century's most important master's thesis and earning a Ph.D. at the
Massachusetts Institute of Technology. His work on anti-aircraft and
digital-encryption systems during World War II planted the seeds for
Information Theory. Shannon reasoned that the same types of digital codes that
protect sensitive information could be used to safeguard it from noise, static
or interference

While pondering such deep thoughts, Shannon often pedaled a unicycle through the halls of Bell Labs. In the early 1950s, his intellectual journey veered toward the relationship between people and machines, and he helped found the field of artificial intelligence. Among the first applications he devised in this area was Theseus, a mechanical mouse that solved mazes in search of a brass "cheese." During this period, Shannon also published one of the earliest proposals for a chess-playing computer.

By "teaching" an electrical mouse to find its way through a maze, Shannon helped stimulate Bell Labs researchers to think of new ways to use the logical powers of computers for operations other than numerical calculation. |

After leaving AT&T in 1956, Shannon joined the faculty at MIT. He formally retired in 1978 and pursued his longtime passions — gadgets and juggling. In fact, one of his favorite creations was a juggling gadget — a robot in the likeness of comedian W.C. Fields.

"I've always pursued my interests without much regard to financial value or value to the world. I've spent lots of time on totally useless things," Shannon said in 1983, perhaps referring to such gizmos as a gasoline-powered pogo stick, a rocket-powered Frisbee, and THROBAC (THrify ROman numerical BAckward-looking Computer), a computer that calculates in Roman numerals.

"He had a wonderful sense of humor and was a great builder of gadgets," Sloane says. "His house was filled with toys, including one device that displayed all the gowns he wore to receive his dozen or more honorary doctorates. He hung them on a circular clothes line, and when he'd flip a switch, the gowns marched around and around."

The man who caused so much excitement died quietly at age 84. But in one of his last papers, Shannon continued pointing the way toward communications' far horizons: "Our government might consider ... listening for evidence of intelligent life on other star systems. Who knows, perhaps E.T. would have words of wisdom for all of us."