Motorola Z6C - Manual (Page 38)

36 basics
TTY Mode can include these options:
When your phone is in a TTY mode, your phone
displays the international TTY mode, the international
TTY symbol, and the mode setting during an active
TTY call.
return to voice mode
To return to standard voice mode, select TTY OFF from
the TTY MODE menu.
option
TTY Full Transmit and receive TTY characters.
TTY + Talk Receive TTY characters but transmit by
speaking into microphone.
TTY + Hear Transmit TTY characters but receive by
listening to earpiece.
TTY Off All TTY modes are turned off.