TeleTypewriter (TTY) mode, also sometimes referred to as Text Telephone, is an accessibility feature intended primarily for individuals with hearing or speech impairments. It facilitates communication by allowing users to type and read text on a device, effectively replacing spoken words with a written format. When activated, the device transmits and receives signals compatible with TTY devices, enabling communication over phone lines. For example, a user can type a message that is converted into a TTY signal and sent to another device, where it’s displayed as text.
The advantage of this mode lies in its provision of an alternative communication method for those who cannot easily use traditional voice communication. It ensures inclusivity and accessibility, enabling participation in conversations and information exchange regardless of auditory or speech limitations. Historically, TTY devices were bulky and separate pieces of equipment. Their integration into mobile devices like smartphones has made this accessibility feature significantly more convenient and readily available to a broader user base.