Zte GRAND X4 User Manual page 82

Set TTY Mode
Your phone is a TTY compatible device. A TTY device can allow
people who have hearing or speech disabilities to communicate
by telephone. Simply connect the TTY device to the phone's
headset jack.
Select a TTY mode for your phone to work with a TTY device, or
turn TTY off.
1. Touch the Home key >
TTY mode.
2. Select one of the following options. Consult your
teletypewriter manufacturer's manual if necessary.
TTY Off: Users who can hear and talk can disable TTY

support.
TTY Full: Users who cannot talk or hear may use this mode

to send and receive text messages through a TTY device.
TTY HCO: Users who can hear, but cannot talk, may use

this mode to listen to conversation of the other party, and
respond via text messages.
TTY VCO: Users who can talk, but cannot hear, may use

this mode to talk through the phone and receive
responses via text messages.
Set Hearing Aids
Your phone supports the Hearing Aid Compatibility (HAC)
function. When you turn on the hearing aid compatibility and use
a hearing aid with a telecoil to answer the phone, it will help you
hear more clearly during the phone call.
> > Settings > Call settings >
82