TTY stands for "teletypewriter," a device initially created to allow individuals with hearing or speech impairments to communicate by sending typed text over standard telephone lines. In modern smartphones, TTY mode replicates this functionality, enabling text-based communication during a voice call. TTY mode includes several settings: TTY Full, TTY HCO (Hearing Carry Over), and TTY VCO (Voice Carry Over). TTY Full allows for text-only communication, while TTY HCO and VCO allow for a combination of voice and text, catering to those who can speak but not hear and vice versa.

To use TTY mode on Android devices, you can search for “TTY” in Settings or open your Phone app and select Call Settings. On a Samsung Galaxy Core Prime, you can enable TTY mode by tapping one of the TTY settings in the Accessibility menu.

If you turn off TTY mode on your phone, you will not be able to receive or make TTY phone calls, but you can use the normal non-TTY functions of your phone again, such as making and receiving basic phone calls and text messages.