Joseph Lechleider, a Father of the DSL Internet Technology, Dies at 82

In the late 1980s, Joseph W. Lechleider came up with a clever solution to a puzzling technical problem, making it possible to bring high-speed Internet service to millions of households. His idea earned him a place in the National Inventors Hall of Fame as one of the fathers of the Internet service known as DSL.

Mr. Lechleider, who died on April 18 at his home in Philadelphia at 82, was an electrical engineer at the Bell telephone companies’ research laboratory, Bellcore. At the time, the phone companies wanted to figure out a way to send signals at high speed across ordinary copper wire into homes, mainly to compete with cable television companies and offer interactive video services.

Applying digital technology was the best route to sidestep the limitations of copper wire, but there was still a barrier. When the data speeds in both directions — downloading and uploading — were the same, there was a lot of electrical interference that slowed data traffic to a crawl.

Mr. Lechleider figured out that such meddlesome interference — known as electrical crosstalk — could be substantially reduced if the download speeds were far faster than the upload speeds. This approach became known as the asymmetric digital subscriber line. And these digital subscriber lines, or DSL, were how big phone companies like AT&T and Verizon brought fast broadband Internet into homes.

“Joe Lechleider’s idea was a simple, elegant solution to the problem,” said John M. Cioffi, an emeritus professor of electrical engineering at Stanford University. “His contribution was essential to the development and spread of the Internet.”

Mr. Lechleider’s death was confirmed by his son, Dr. Robert Lechleider, who said the cause was cancer of the esophagus. Besides his son, he is survived by his wife, Marie; his daughter, Pamela; and four grandchildren.

Joseph William Lechleider was born on Feb. 22, 1933, in Brooklyn. He attended Brooklyn Technical High School and earned his undergraduate degree from Cooper Union and a Ph.D. from the Polytechnic Institute of Brooklyn.

Upon graduation, he went to work for General Electric for a few years, and in 1955 he joined Bell Labs. After the 1982 court order breaking up American Telephone & Telegraph, the research arm of the regional Bell companies was established as Bellcore.

Mr. Lechleider’s insight about how to increase data speed came when he was 55. He had spent decades studying signal processing, so he was deeply grounded in the field. But Mr. Lechleider, according to Mr. Cioffi, was something of an iconoclast in a large, often bureaucratic organization.

“He was not afraid to take a risk and fight for a new idea,” Mr. Cioffi said.

Mr. Lechleider was fueled by a wide-ranging curiosity, his son said. Two walls of his study, he recalled, were bookshelves, double-stacked, with books on subjects ranging from physics to philosophy. The study also had a bust of Albert Einstein, whom Mr. Lechleider revered for advancing ideas that challenged accepted wisdom.

Digital subscriber lines were not an immediate success. Early versions were not capable of video-on-demand services, the market the Bell companies originally wanted to enter. And when the Internet began to take off in the 1990s, most consumers went online using dial-up modems, which increased the demand for second phone lines in homes. That was a good business for the phone companies, and a familiar one. Why opt for this new DSL technology?

“There was considerable skepticism,” Mr. Lechleider said in an interview with The Wall Street Journal in 2003. “There were people who didn’t want to deploy it. There were people who didn’t think it would work. Many of them weren’t sure there was a market for it.”

But as the web added more data-rich images, music and video, the demand for affordable, higher-speed communications services surged. And DSL technology afforded the phone companies a path to do that for years without having to undertake the costly alternative of installing fiber-optic cable into homes.

Mr. Lechleider contributed a key idea. But it was younger engineers like Mr. Cioffi who developed DSL modem technology.

The inexpensive cleverness of DSL technology, industry analysts say, meant the phone companies did not invest heavily to upgrade their broadband systems, as did the cable companies, like Comcast and Time Warner Cable. The cable operators initially feared competition from satellite television, but their investment paid off, allowing them to offer ever-faster Internet service.

“DSL allowed the phone companies to milk another two decades out of their copper infrastructure,” said Craig Moffett, a telecommunications analyst. “But the phone companies now find themselves far behind the cable companies in the speeds they can offer.”

Mr. Lechleider was not an early adopter of Internet technology. But when he signed up for high-speed service, he chose cable.

Yet his son recalled first getting DSL service years ago in his own home and, realizing how much faster it was than dial-up service, thinking of his father. “I loved him for it,” he said.

Correction: May 4, 2015

An earlier version of this obituary misidentified the school from which Mr. Lechleider received his Ph.D. It was the Polytechnic Institute of Brooklyn, not New York University’s Polytechnic School of Engineering. (The school is now part of N.Y.U. but was not at the time.)

Correction: May 4, 2015

An earlier version of a picture credit with this obituary omitted the name of the photographer. The photo was taken by Julia Rosedale.

Originally published in The New York Times