He did not use a teleprompter himself until he was 88, while rehearsing his speech for induction into the Cable Television Hall of Fame, said Thomas Gallagher, a close friend.
Schlafly helped start the TelePrompTer Corp., eventually becoming its president and accepting an Emmy Award for the company in 1999 - a few years after winning one himself 1992 for his work in developing the first cable system permitting subscribers to order special programs. He held 16 patents, Gallagher said.
"Hub Schlafly was the cable industry's most innovative engineer and, at the same time, one of its ablest executives," Charles Dolan, the chairman of Cablevision, said in a statement Tuesday. "Whether you were his friend or competitor, he was always congenial and supportive and probably had more friends than anyone."
Schlafly was born Aug. 14, 1919, in St. Louis. He graduated from Notre Dame University, where he studied electrical engineering. He worked for General Electric and the MIT Radiation Laboratory before joining 20th Century Fox in New York City in 1947.
Actor Fred Barton Jr. wanted a way to remember his lines and approached his friend Schlafly, said Laurie Brown, author of the book "The Teleprompter Manual." Schlafly conjured an idea and took it to Irving Berlin Kahn, nephew of composer Irving Berlin and vice president of radio and television at 20th Century Fox.
The result - a monitor facing the person appearing on screen and rolling a script at reading speed - was named the TelePrompTer, which made its debut in 1950 on the soap opera "The First Hundred Years," Brown said.
"It revolutionized television and improved the quality of on-air performers," said Jim Dufek, a professor of mass media at Southeast Missouri State University. "It also made the politicians look smarter because they were looking right into the camera."
Every president since then has used the device - now also such a staple of television news that occasional technical glitches can turn a news report into unintentional comedy.
In the 1970s, TelePrompTer Corp. owned cable franchises in 140 markets and served about 1.4 million customers.
A graveside service for Schlafly is planned Thursday in Louisville, N.Y.