A TTY (or TDD) is a typing device that once played the central role in Deaf telecommunications—how Deaf and hard of hearing people made phone calls. Long before texting, smartphones, videophones, or relay services existed, Deaf people were way ahead of the technological curve.
While most Deaf people no longer use them today, the TTY remains an important part of Deaf history. Modern technology still hasn’t quite been able to replace every capability in TTYs, so they remain in service for those who may need them and are still required in public spaces and some emergency systems.
Photo by Sound for Light.
In this article, I’ll explain what TTYs are, why some people called them TDDs, how they worked, and why you’ll still see them in public places even though they are not used by the majority of Deaf people anymore.
I’ll never forget getting my first TTY. Since I was was raised orally, the assumption was I could hear as well as I could talk–which was not the case. So getting a TTY was not unlike seeing the sun rise for the first time.
Suddenly, making phone calls wasn’t a stress-y guessing game. No bluffing. No asking someone to call for me. Everything was just clear. Heck, calling my car mechanic was a joy. For many of us, the TTY didn’t just mean access—it gave us independence.
What is a TTY or TDD?
For Deaf people, TTYs opened the door to phone communication without relying on hearing intermediaries. For the first time, Deaf callers could reach doctors, employers, or friends directly—something that simply wasn’t possible before the 1960s.
Accessible TTY use became possible because of Deaf inventor Robert Weitbrecht, who—along with fellow Deaf professionals James Marsters (an orthodontist) and Andrew Saks (an engineer)—adapted newsroom teletype technology so Deaf people could use telephone lines. This was Deaf-led innovation meeting a Deaf access need.
From the mid-1960s through the early 2000s, TTYs spread through Deaf homes, schools, clubs, and workplaces across the country. For decades, they were to Deaf life what smartphones are today: something we saw everywhere in our lives.
TTYs in Everyday Deaf Life
At the height of their use, nearly every household with a Deaf person had a TTY. They sat in living rooms, bedrooms, dorm hallways, school offices, Deaf clubs—anywhere a phone needed to be accessible. Before texting and video relay, TTYs were the only way to communicate over phone lines by typing instead of speaking.
Even though TTYs are rare in people’s homes today, they remain available to those who need them. That would include those who live in rural areas without consistent access to internet or cell service necessary to power videophones or smartphones.
TTYs also still appear in airports, hospitals, government buildings, and emergency systems because accessibility laws require them, but they’re probably used as often as regular public pay phones.
Photo courtesy of the Smithsonian Institution.
What Does “TTY” Mean?
“TTY” is short for TeleTYypewriter—a machine originally used in newsrooms to transmit typed messages. Deaf innovators adapted this technology so typed messages could travel through telephone lines and appear on a small screen (or print on a paper roll) on the other end.
What Does “TDD” Mean (and Why Two Terms)?
“TDD” stands for Telecommunications Device for the Deaf, a label used mostly by hearing institutions, phone companies, and government agencies. Technically, “TDD” and “TTY” referred to the same device—but the naming came from very different perspectives.
Hearing organizations framed the device from a medical or service-oriented viewpoint: a special device for “the Deaf,” rather than acknowledging that the technology was invented and refined by Deaf people themselves.
And let’s be honest… hearing people have a long history of choosing labels for us without actually consulting us.
Why Deaf People Mostly Say “TTY,” Not “TDD”
Within the Deaf community, “TTY” has always been the preferred and culturally grounded term. It reflects Deaf history and ownership of the technology. “TDD,” feels like an external label created by outsiders—because that’s what it is.
How TTYs Worked
A TTY call connected two machines using a standard telephone line. Instead of using voice, the TTY sent sound tones that were converted into text on the other person’s screen. Because you couldn’t interrupt the way you can in voiced conversation, TTY users followed a unique communication etiquette:
Infographic by Sound for Light.
GA (“go ahead”) → your turn
GA to SK → “I’m finished—anything else?”
SK → “stop keying”
SKSK → final goodbye
If you needed to call a hearing person, you used a relay service, where an operator voiced your typed words and typed back the spoken responses. It seems tedious now, but at the time, it was revolutionary.
Are TTYs Still Used Today?
TTYs are rare now, but they haven’t disappeared completely. Some older Deaf or DeafBlind adults still use them out of familiarity, and certain hospitals, government buildings, and agencies are still required to provide TTY access. Emergency 911 centers must also maintain TTY compatibility by law—even though more modern options now exist.
If you go to most government websites, among the listed phone numbers, you’ll probably see one with “TTY” following it. This means that office can be reached directly by TTY (without having to go through a relay).
Modern Alternatives to the TTY
Today, Deaf communication has shifted to faster, more natural tools. Video Relay Service (VRS) allows Deaf callers to use ASL in real time through interpreters. Text messaging replaced the slower, turn-based style of TTY conversations. Real-Time Text (RTT) is a feature built into smartphones that lets people type instantly without special equipment.
The TTY didn’t disappear— it paved the way for new tools that now serve Deaf communication in a digital world.
FAQs
FAQ #1: Is a TTY the same thing as a TDD?
Yes — same device, different terminology.
FAQ #2: Can you still buy or use a TTY today?
Yes! While they are rarely used by the majority of deaf and hard of hearing people, they are still supported by laws and emergency systems.
FAQ #3: Why do some buildings still have TTY machines?
These are to comply with ADA requirements + emergency access. In theory, there needs to be a way for ALL people who cannot use the typical phone to make an emergency call, the TTY covers this need better than a videophone, because not all deaf and hard of hearing people use sign language. Also, TTYs can be used with analog phone systems so they will work without internet.
FAQ #4: What does GA or SK mean on a TTY?
These are TTY conversation etiquette codes. GA = “Go Ahead” (to signal the other person’s turn) SK = “Stop Keying” (to end the phone call)
FAQ #5: Do Deaf people prefer video calling over TTY now?
Yes — VRS and smartphones largely replaced TTY use. For late-deafened individuals or those who prefer to read captions and speak back to the other caller, captioned telephones are a popular replacement choice. Of course, texting and email have become mainstream modes of communication within the larger community–Deaf-friendliness built in!