Formally known as the teletypewriter or the text telephone, the TTY is a device that allows deaf individuals to communicate by typing messages and sending them along phone lines. Essentially, a TTY works something like a fax machine without paper. Although similar devices have been around for more than 100 years, the modern TTY made its first appearance in the 1960s.
Deaf physicist Robert Weitbrecht and two deaf colleagues invented the modern TTY by connecting two Teletype machines with a telephone wire in 1964. An acoustic coupler translated one Teletype's electrical signals into tones that traveled through the wiring to the other Teletype, where a coupler translated the tones back into electrical signals and printed the message on the machine. By 1966, nearly 20 TTYs were in use.
The earliest TTYs were large desk-like machines weighing up to 300 pounds, each with a keyboard and paper for printing messages. The machines were attached to separate phones. Some called them "clunkers" or "monsters," and they were extremely noisy to use. However, as deaf professor Harry G. Lang at the National Technical Institute for the Deaf said, before TTY became available, he had to drive to friends' homes to talk to them and he had to ask hearing people for help making phone calls.
TTYs shrank in size in the 1970s. Some weighed less than 5 pounds, many were portable, and all became increasingly popular. But the popularity of TTYs did not peak until the 1990s, before the Internet and text messaging reduced the need for them.
In the 1980s, the TTY underwent several advances. TTY modems made their first appearance in this decade, linking TTYs to computers. Many locations also began including TTY machines on shelves or in drawers below pay phones, and today most pay phones have TTYs.
Today's TTYs are small, flat keyboards--no bigger than a laptop--each with a telephone perched above the keyboard. Between 1999 and 2006, the number of TTYs listed in the U.S. Blue Book, a directory of TTY users, dropped from 55,000 to 30,000. In recent years, text messaging and the Internet have made it easier for deaf individuals to communicate without TTYs, but many deaf people still use the devices, and some even plug them into their cell phones.
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