While it pioneered the concept of wireless TV remote control, the Flashmatic had some limitations. It was a simple device that had no protection circuits and, if the TV sat in an area in which the sun shone directly on it, the tuner might start rotating.

Development Challenges
Zenith management loved the concepts proven by Polley's Flashmatic and directed his engineers to develop a better remote control. First thoughts pointed to radio. But, because they travel through walls, radio waves could inadvertently control a TV set in an adjacent apartment or room.

Using distinctive sound signals was discussed, but Zenith engineers believed people might not like hearing a certain sound that would become characteristic of operating the TV set through a remote control. It also would be difficult to find a sound that wouldn't accidentally be duplicated by either household noises or by the sound coming from TV programming.

The Birth of Space Command
Zenith's Dr. Robert Adler suggested using "ultrasonics," that is, high-frequency sound, beyond the range of human hearing. He was assigned to lead a team of engineers to work on the first use of ultrasonics technology in the home as a new approach for a remote control.

The transmitter used no batteries; it was built around aluminum rods that were light in weight and, when struck at one end, emitted distinctive high-frequency sounds. The first such remote control used four rods, each approximately 2-1/2 inches long: one for channel up, one for channel down, one for sound on and off and one for power on and off.

They were very carefully cut to lengths that would generate four slightly different frequencies. They were excited by a trigger mechanism -- similar to the trigger of a gun -- that stretched a spring and then released it so that a small hammer would strike the aluminum rod. The device was developed quickly, with the design phase beginning in 1955. Called "Zenith Space Command," the remote control went into production in the fall of 1956.

Quarter Century of Ultrasonic Remotes
The original Space Command remote control was expensive because an elaborate receiver in the TV set, using six additional vacuum tubes, was needed to pick up and process the signals. Although adding the remote control system increased the price of the TV set by about 30 percent, it was a technical success and was adopted in later years by other manufacturers.

In the early 1960s, solid-state circuitry (i.e., transistors) began to replace vacuum tubes. Hand-held, battery-powered control units could now be designed to generate the inaudible sound electronically. In this modified form, Dr. Adler's ultrasonic remote control invention lasted through the early 1980s, a quarter century from its inception.

Today's Infrared Remote Controls
By the early 1980s, the industry moved to infrared, or IR, remote technology. The IR remote works by using a low frequency light beam, so low that the human eye cannot see it, but which can be detected by a receiver in the TV. Zenith's development of cable-compatible tuning and teletext technologies in the 1980s greatly enhanced the capabilities and uses for infrared TV remotes.

Today, remote control is a standard feature on other consumer electronics products, including VCRs, cable and satellite boxes, digital video disc players and home audio receivers. And the most sophisticated TV sets have remotes with as many as 50 buttons.

Zenith developed the world's first wireless trackball TV remote control, called Z-Trak. The remote works like a computer mouse - click the ball and a cursor appears on the TV screen. Roll the ball and the cursor activates control menus hidden in different corners of the screen. Then, activate something from those menus - bass, treble, contrast, color temperature, channel... whatever.

Manufacturers used to only make remote controls that operated one TV set.  However, they are now making universal remote controls that can operate any TV set.  Experts predict that someday remote controls will control almost every device in the home.

HOW IT WORKS:
Hard Wired: The "Lazy Bones" used a cable that ran from the TV set to the viewer. A motor in the TV set operated the tuner through the remote control. By pushing buttons on the remote control, viewers rotated the tuner clockwise or counterclockwise, depending on whether they wanted to change the channel to a higher or lower number. The remote control included buttons that turned the TV on and off.

Flashmatic: Operated by means of four photo cells, one in each corner of the TV cabinet around the screen. The viewer used a highly directional flashlight to activate the four control functions, which turned the tuner clockwise and counter-clockwise and which turned the sound and power on and off.

Ultrasonic:  The "ultrasonics," that is, high-frequency sound, beyond the range of human hearing. The original Space Command remote control was expensive because an elaborate receiver in the TV set, using six additional vacuum tubes, was needed to pick up and process the signals. In the early 1960s, solid-state circuitry (i.e., transistors) began to replace vacuum tubes. Hand-held, battery-powered control units could now be designed to generate the inaudible sound electronically.

Infrared: The IR remote works by using a low frequency light beam, so low that the human eye cannot see it, but which can be detected by a receiver in the TV.

FACTS:

• In 1999, more than 99 percent of all TV sets and 100 percent of all VCRs sold in the U.S. were equipped with remote control.
• More than 9 million ultrasonic remote control TVs were sold by the industry during the 25-year reign of Dr. Adler's invention.
• Zenith sales people were against using batteries in the remote control. In those days, batteries were used primarily in flashlights. If the battery went dead, the sales staff said, the customer might think something was wrong with the TV.
• Early remote controls were expensive because an elaborate receiver in the TV set, using six additional vacuum tubes, was needed to pick up and process the signals. Adding a remote control system increased the price of the TV set by about 30 percent.