How Does TTY Work?
Text telephone (TTY) mode is used for text communication over a telephone line. A TTY device must be connected to the computer to interpret the modified audio; otherwise you might experience poor audio quality during the call. Using TTY mode in a conference call may also cause audio quality issues. TTY mode is turned off by default. You can turn on TTY mode by clicking Phones in the Lync – Options dialog box. You will then need to sign out of Lync, and then sign back in to use the feature.