Touch tone phones are a type of telephone that use a keypad with buttons to dial numbers. Each button emits a specific sound, known as a tone, when pressed. This technology replaced rotary dial phones, allowing for quicker and more efficient dialing. Introduced in the 1960s, touch tone phones became popular due to their ease of use and reliability. They paved the way for modern communication devices, including mobile phones and smartphones. Today, touch tone technology is still used in various applications, such as automated phone systems and interactive voice response systems.