Mobile Number Tracker
Trace Mobile Number Earn Money Online

TTY Mode: Meaning and Use in Mobile Phones

tty phone in mobile phones
Samyak Lalit | November 4, 2016 (Last update: March 20, 2020)

Samyak Lalit is an Indian author and disability rights activist. He is the principal author and founder of projects like TechWelkin, WeCapable, Viklangta, Kavita Kosh among many others.

“What is the meaning of TTY mode in my mobile phone?”, one of the TechWelkin readers sent this query last week. And have selected this question to answer in today’s article. A teletypewriter (TTY) is a device used for communication by hearing-impaired and speech-impaired people. User types the message on a TTY machine and the machine transmits the message through a telephone line or mobile phone signal. The TTY machine on the recipient’s side will get the message and display it to the user on a text display screen.

What is TTY mode in Mobile Phones?

When a mobile phone user goes to her phone’s settings, they often find an option labelled as TTY mode off. People wonder what is this TTY mode and what’s the use of it.

TTY mode is required to be enabled if you want to use a teletypewriter (also known as teleprinter) machine with your mobile phone. When TTY mode is on, the mobile phone will communicate with you through a TTY machine.

NOTE: If TTY mode is on, some mobile phones may lose ability to take or make voice calls. Some other features of your mobile phone may also not work as expected. So, if you do not really intend to use TTY terminal, you should keep TTY mode off.

tty mode in mobile phones

TTY machines can be connected with both telephone landlines and mobile phones.

When TTY mode is on and a TTY machine is connected with a mobile phone, the device simply uses mobile network to send and receive data. Users communicate more or less like using online chat applications.

How to Enable TTY Mode?

If you have a teletypewriter machine, connect it to the audio jack of your mobile phone and the go to Settings of your phone. Different mobile phones may show TTY mode in slightly different locations. But mostly you will find it in General settings (or Settings > Call settings).

Tap on the TTY mode option. You may get a menu asking you to choose one of the following TTY modes:

  • TTY Off (it would be the selected option)
  • TTY Full
tty mode settings

TTY Mode Settings

TTY Full

This option should be selected if both sender and receiver have TTY machines connected to their mobile phones. The two-way communication will take place through TTY.


You should select this option if caller is hearing-impaired but can speak. In the Voice Carry Over (VCO) option, the caller sends her messages though voice and receives messages on a TTY text display.


The Hearing Carry Over (HCO) option is used when the caller is is speech-impaired but can hear. The caller will send messages by typing them on a TTY machine and will receive messages by listening to them on phone.

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

Yes, you can! If you do not have a TTY machine, you can make the call to a hearing-impaired person through Telecommunications Relay Service (TRS). In many countries, TRS is available as a toll free and round the clock service. To use TRS, you need to call the TRS number and ask the TRS operator to connect you to the hearing-impaired receiver. Then whatever you will speak, the TRS operator will type that on a TTY machine and the text will be transmitted to to the call receiver (who will see the text on her TTY text display).

In the United States, 711 is the Telecommunications Relay Service number. Emergency TTY calls should be made directly to the regular 911 number.

We hope now your questions regarding TTY mode in mobile phone are answered. Should you have any further questions, please feel free to post them here. The TechWelkin team and our reader community will try to answer your questions. Thank you for using TechWelkin!


5 responses to “TTY Mode: Meaning and Use in Mobile Phones”

  1. Normand Dubois says:

    I appreciate the fact that deaf people need to talk, but there should be a safety guard to prevent this thing from coming on by itself. At first I didn’t know about this device and my phone kept telling me to “Turn off the TTY mode” (It prevented my phone from going on video mode) and it took me about a week (on and off time) to figure it out by asking questions to the google service on my phone. I have better things to do thank you.

    You should first have a one liner explaining what this is, and then another short one liner to simple give the steps/actions to turn this feature off.

    Thank you for reading me!

  2. Abhishek says:

    I am using Bluetooth device in my car for music through mobile, but this device is not supporting in call.
    Is there any setting in TTY so that the device can also support the calls.

    • Jenn Karr says:

      Can you just simply text a TTY number and receive texts back from that number without turning on the TTY mode on my mobile phone?

  3. S Chakrabarty says:

    My phone is by mistake gone under TTY mode. How can I put it to normal working set. Now I get a talk back always, and I need to double tap on all icons or apps. Pl guide
    S Chakrabarty

Leave a Reply

Your email address will not be published. Required fields are marked *