If you want to use your Windows Phone with a TTY/TDD to make a phone call:
Plug your phone into the TTY using the appropriate cable and connector for the headset jack.
In the App list, tap Settings
Under TTY/TDD, tap to switch from Off to Full mode.
Your mobile operator may offer other modes as well. If so, tap the one you want to use.
Turn on the TTY.
That's all you need to do—now you're ready to make your call. See the documentation for your TTY for more info on how to use it.
TTY is an abbreviation for teletypewriter, also known as a text telephone or a telecommunication device for the deaf (TDD). This device allows people who are deaf, speech impaired, or hard of hearing to type messages to anyone else who has a TTY, using a telephone line.
Some phones may not support Telecoil and TTY/TDD.
Article ID: 10668 - Last Review: 17-May-2016 - Revision: 16