Samsung Galaxy S 5 User Manual page 274

2. Tap Additional settings > TTY mode.
3. Tap TTY Full, TTY HCO, or TTY VCO to turn TTY mode on.
– or –
Tap TTY Off to turn TTY mode off.
 Your phone's TTY mode is set.
Note: When enabled, TTY mode may impair the audio quality of non-TTY devices connected to the
headset jack.
Settings 264