Bell Atlantic Awarded Patent for Rate-Adaptive DSL Technology
Patent Covers Techniques Used to Dynamically Adapt DSL
Signaling to the Interference on a Copper Telephone Line
December 14, 1998
NEW YORK -- Bell Atlantic has been awarded a significant, broad-ranging patent stemming from
the pioneering work the company did with digital subscriber line (DSL) technology in the early
1990s. Bell Atlantic has already begun efforts to license the technology covered by this patent
across the industry.
The U.S. patent -- number 5,812,786 -- was issued to Bell Atlantic Network Services, Inc., on
September 22, 1998. The inventors of record are John Seazholtz, Wendell Sims and Kamran
Sistanizadeh. Mr. Seazholtz, who has since retired, was Bell Atlantic's chief technology officer in
1995 when the patent application was filed. The new DSL patent is the 302nd to be awarded Bell
Early plans for DSL technology were for the delivery of video programming at fixed transmission
rates. Bell Atlantic's newly issued patent covers rate-adaptive DSL, which makes it possible to
change the rate of a DSL transmission "on the fly."
The effect of using Bell Atlantic's invention is to greatly increase the flexibility of DSL. The
enhanced flexibility extends the effective "reach" of the technology, increasing the number of
households that can be provided a high-speed link. It also expands the range of communications
services that DSL can support, such as accessing the Internet and telecommuting.
"DSL technology will enable millions of homes to be equipped with high speed connections to the
world's telecommunications networks during the next five to ten years by using existing telephone
lines, even while these same lines continue to be used for voice telephone calls," said Larry
Babbio, president and chief operating officer, Bell Atlantic. "New forms of interactive, TV-like
communications will result that will transform the way people work and play in the next
millennium. Bell Atlantic is proud of the role its innovation and breakthroughs have played in
turning this technology into a range of useful services."
Across the country, both incumbent telephone service providers and others have already begun to
offer high-speed Internet access services using rate-adaptive DSL technology that is now patented
by Bell Atlantic. Bell Atlantic itself launched a set of Infospeed sm DSL services on Oct. 5.
These are now available in selected communities in Pittsburgh, Philadelphia, Washington, D.C.,
and Northern New Jersey, with new markets being opened each week. The pace of deployment is
expected to accelerate across all segments of the industry next year as international standards for
the technology are approved.
Bell Atlantic first began experimenting with DSL technology in 1992. It was in October 1992 that
the company announced plans to use DSL to develop a service that could deliver feature films,
television dramas, educational programs and more, immediately after a customer placed an order.
The plan was to digitally encode movies and TV programs using compression algorithms
conforming to international standards set by the Motion Pictures Expert Group, or the so-called
MPEG 1 and MPEG 2 standards. The plans called for compressed videos to be transmitted across
the public switched telephone network at one of several fixed data rates, depending on the nature
of the source material and whether it was pre-recorded or broadcast live.
Bell Atlantic moved forward with its plans and in April 1993 became the first company in the
world to deploy DSL technology outside a laboratory and to use it to deliver video-on-demand
programming. Thus was initiated a development effort that extended for more than three years
and involved thousands of customers in the United States and Italy. Bell Atlantic aspired to
launch a new industry, dubbed Interactive Multimedia Television or IMTV, that would deliver not
just videos on demand, but also shopping services, enhanced education, news-on-demand and
much more. An entire generation of revolutionary "new media" applications was envisioned.
Concurrent with Bell Atlantic's development of IMTV capabilities, however, the World Wide
Web became increasingly ubiquitous. By 1995 it was apparent that new media services would
become widely available via the personal computer and the Internet first, not through the TV set
and IMTV technology. Accordingly, Bell Atlantic had already begun to redirect its new media
development efforts to capitalize on the growing demand for Internet access and World Wide
Web-based services, even while the company continued to develop a video-on-demand service. It
was in this context that Bell Atlantic invented the new techniques for DSL technology, which led
to the patent that was awarded this September.
Bell Atlantic has been awarded 321 patents and has 163 patents pending. The company also has
20 that have been "allowed," which means that their award is imminent, for a total of 504 patents
awarded or in the pipeline -- more than twice as many as any other regional Bell company.
Bell Atlantic is at the forefront of the new communications and information industry. With 42
million telephone access lines and eight million wireless customers worldwide, Bell Atlantic
companies are premier providers of advanced wireline voice and data services, market leaders in
wireless services and the world's largest publishers of directory information. Bell Atlantic
companies are also among the world's largest investors in high-growth global communications
markets, with operations and investments in 23 countries.