Phone

The essential telecommunications device: it transmits the human voice via electronic signal, evolving from Alexander Graham Bell's 1876 patent (U.S. 174,465) to the modern, global smartphone.

The phone is the world's most-used telecommunications device: it converts sound into electronic signals for immediate, two-way voice transmission. Its foundation was Alexander Graham Bell’s 1876 patent, but the form factor shifted dramatically with Motorola’s 1973 DynaTAC 8000X (the first handheld mobile) and Apple’s 2007 iPhone (the first fully realized smartphone). Today, the Public Switched Telephone Network (PSTN) still relies on a 48-volt standard, yet billions of users globally now operate 5G-enabled, pocket-sized computers for all communication: this technology defines global connectivity.

https://www.britannica.com/technology/telephone