Aside from the telephone, Alexander Graham Bell also invented the photophone and the graphophone. The photophone was created as part of a research project while Bell was located at Volta Laboratory. The invention was able to utilize light as a method to transmit sound without requiring a wire connection.
While the photophone was a technological success, the product did not become commercially viable during Bell's lifetime. The graphophone was developed to advance the technology of sound recording and playback. The invention was perfected for commercial use through a collaboration effort between Bell, his cousin Chichester A. Bell and Charles Summer Tainter.