tty mode meaning
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TTY means “teletypewriter” or “text telephone” and is a specialized interface for transmitting text over audio signal through traditional phone lines.

As for the common meanings, TTY normally refers to a communication mechanism that allows text communication over standard phone line connections.

enable tty mode on android

In simple terms, it is a device that allows people who are deaf, hard of hearing, or who have speech or language disabilities, to communicate over the telephone.

We should, however, point out that while these are the more common meanings, there may be other meanings as well. The mechanism does this by converting the text input to audio and then decoding the audio back into text at the point of reception. Let’s explain this a little further.

How Does TTY Work?

TTY Uses

As we already mentioned, TTY devices are machines that are specifically and specially designed to allow hearing and speech impaired people to communicate with one another over long distances by displaying text messages instead of conveying sound.

This therefore means that both parties require TTY devices to communicate with one another. Today, many cell phones (especially android phones) have TTY capabilities.

If your phone is TTY enabled, then it may be connected to a TTY device, and you can then communicate with someone else who has a TTY device.

There are many uses of TTY. For example, you can easily make a TTY call from your android phone to a TTY box on a land line. You can also receive a call in a similar manner.

TTY History

Originally, TTY services were developed for use in the news or journalism field because rapid text communication was necessary in that industry.

However, as time rolled on, by the 1960s the technology was also adapted for use over standard phone lines.

Since a TTY machine can send and receive text information over a standard telephone connection, it allows hearing-impaired people to communicate easily.

As such, the system was adopted as a means for deaf and hearing impaired persons to communicate over standard telephone lines.

Because of this, the system was sometimes referee to as a text telephone (TT) or a telecommunication device for the deaf (TDD).


how does tty work

However, the term TTY is a general term that covers all the different types of TDDs available, according to the organization Telecommunications for the Deaf. So if you hear the question what does tdd mean? You should know it covers a wide range of Telecommunications Device for the Deaf.

Enabling and Disabling TTY

Enabling TTY – General

As we have already pointed out, TTY mode must be enabled if you want to use a teletypewriter (also known as teleprinter) machine (TTY machine) with your mobile phone.

In other words, you should turn TTY on before connecting your phone to a TTY device. When you turn on TTY mode, the mobile phone will communicate with you through a TTY machine.
Also, enabling TTY mode may cause you to lose the ability to receive regular (non-TTY) calls and text messages. In fact, you may even be unable to open certain applications on your smartphone while TTY is enabled. If you want to activate TTY on an android phone, here’s how you go about it:

I. If you have a teletypewriter machine, connect the device to the audio jack of your mobile phone and then go to Settings on your phone. While each phone is different and so different mobile phones may show TTY mode in slightly different locations, you can usually find the TTY option under the “General Settings” or just “Settings” menu.

II. After going to “Settings”, find your “Call Settings”

III. Inside call settings, search for “TTY Mode” or something similar.

IV. Select the TTY mode you want from the list provided. The most common TTY modes are “TTY Off”, “TTY Full”, “TTY HCO” and “TTY VCO”.

It is important to note that you should only use the TTY settings if you are going to connect your android phone to a TTY device. On all other occasions, use the text messaging and e-mail options for text communication.


How To Enable TTY On iPhone and Android

enabling tty

Let’s get into some specifics now. This is how you can start TTY on iPhone and Android:

On iPhone

• First, select the ‘Settings’ option and choose ‘Phone’.
• Turn on the TTY mode by moving the slider to the ‘On’ position.
• Now use an audio jack or adapter to connect your iPhone and the TTY device.
• That’s it! At this point you can start communicating using TTY.

On Samsung Galaxy

• First, go to ‘Settings’ and select ‘My Device’.
• Next, choose, ‘Call’, under which you will find the option ‘TTY mode’.
• When you select the TTY mode, you will have an option to choose from TTY Off, TTY Full, TTY HCO, and TTY VCO.


Disabling TTY

Turning off TTY mode will return your phone to its regular operation, allowing you to make and receive regular calls and messages again.

turn tty mode off

Of course, disabling TTY means you won’t be able to receive or make TTY phone calls, however, your phone should still function as normal.

Importantly, keep in mind that you should enable TTY ahead of time if you’re expecting a TTY phone call.
To disable TTY, follow the same instructions as above, except you will choose to turn-off the TTY mode chosen.


Variants of TTY: Other TTY Meanings

There are several variants to TTY, they are Full, HCO and VCO. Let’s break them down:

Full TTY: Full TTY indicates that there is text-only communication on both sides of the phone call.

HCO: HCO stands for “Hearing Carry-Over”. This feature is designed for those who are unable to speak but can hear clearly. This typically means that you hear a voice read the incoming text and you type the outgoing text.

In most cases, HCO settings are normally amplified for the hard of hearing. Since this is done, it is important that you be cautious with headsets and hands-free ear pieces when enabling HCO because high volumes may cause hearing damage or even hearing loss. That’s TTY HCO.

VCO: VCO stands for “Voice Carry-Over”. This feature is meant for people who are able to talk but are hearing-impaired. A hearing-impaired person can often easily communicate verbally but can’t hear well and so needs to be sent typed messages. This means that you speak the outgoing text and receive a text message back. That is TTY VCO.


TTY Communication Etiquette

As we mentioned before, TTY technology is one way at a time. In other words, it is half-duplex. To facilitate easy commutation, TTY users have developed a shorthand method of transmitting messages:

Placing A Call: When placing a call, it is polite to wait quite a few rings. In fact, wait at least seven rings for an answer since a hearing-impaired person may take longer to notice an incoming call.

Answering A Call: A typical greeting a hearing impaired person will use when answering a call is “GA”. “GA” indicates that you should “go ahead” and type.

It is similar to how people using walkie talkies or other radio communications say “over” which of course indicates that your message is done and the other person should go ahead and start transmitting.

In other words, it is normally used at the end of a sentence, signifying that it’s the other person’s turn to speak.

Ending A Call: End a call with “SK”. This indicates that you’ve “stopped keying” on your side.


TTY Compatibility

Most phones are only compatible with select TTY machines. The best way to determine which devices are compatible with your TTY phone, it is best to check with your phone’s manufacturer.

More importantly, check with the manufacturer to ensure that your phone supports digital wireless transmission.

In either case, your regular phone and your TTY phone will connect using a special connector cable that plugs into your phone’s headset jack.


TTY 9-1-1 Emergency Calling

If you are a TTY user, you may be disappointed by its emergency calling abilities. It is generally recommended that users make emergency calls by other means than TTY. This is because TTY calls to 9-1-1 may be corrupted when received by public safety answering points (PSAPs).

More often than not, this makes the communication unintelligible. It is an ongoing problem that the PSAP community is working to resolve, but for now all we can say is that it seems to be due to TTY equipment or software used by PSAPs.

Wireless There are several ways of doing this including TRS, analog cellular, and landline communications. However, if TTY is the only option at your disposal, go ahead and use the regular 911 number.

Should My TTY Mode Be On Or Off?

If you want to utilize a teletypewriter (also known as a teleprinter) with your mobile phone, you must enable TTY mode. When this mode is enabled, the phone communicates with you via a teletypewriter machine. However, some mobile phones may lose the ability to take or make normal voice calls if TTY mode is enabled.

What Happens When You Call A TTY Number?

TTY is a tool created to aid people with visual, speech impediments or hearing problems with operating their mobile phones by enabling them send texts that can be translated into audios and send audios that can be translated into words. To communicate with a TTY number, the function has to be enabled on both ends or the call goes through a TRS operator (Telephone Relay Service).

Who Are TTY Calls For?

The Text Telephone Relay (TTY) or Telecommunications Relay Service (TRS) is for human beings with such disabilities as blindness, deafness, speech, hearing and sight impairments and wish to send and receive audio and text messages with other people.

Are TTY Phones Still Used?

The TTY service is now generally available to consumers for use as long as their digital devices and smartphones are TTY compatible. Phones which are not TTY enabled can also be passed through the Relay Service to patch them through to a TTY user.

Don’t Have TTY? You Can Still Communicate With The Hearing Impaired

Can you communicate with a hearing-impaired person if you don’t have TTY?

Yes! Modern technology makes it possible!

The major thing preventing many people from using TTY is often because they believe they must have a TTY machine to do so.

However, the fact is that you can use TTY without a TTY machine. To do this, you can make the call to a hearing-impaired person through the Telecommunications Relay Service (TRS).

Better yet, in many countries, TRS is not only a 24 hours service, but it’s often toll free as well. There are two types of TRS:

Operator TRS: All you need to do in order to use TRs is to call the TRS number and ask for the operator who will connect you to the hearing-impaired person you wish to call.

Once you are connected, then whatever you speak, the TRS operator will type your words on a TTY machine and the text will be transmitted to the call receiver (the hearing impaired person who will then see the text on his/her TTY text display).

Software TRS: Instead of an operator, voice recognition software is used to convert the speaker’s words into text which is then sent to the receiver for display.
In the United States, the Telecommunications Relay Service can be reached at 711.



So, we have answered the questions “what is TTY”, “what is TTY used for” and everything else important about TTY.
According to the Federal Law of America, people who are speech and hearing-impaired deserve to be able to communicate as easily as possible.

TTY has been introduced with the thought of providing these people with an easy means of communication using standard phones. According to the Title IV of the Americans with Disabilities Act, the TTY service should be extended free of charge by every state.