generate questions: Bell and his assistant Charles Sumner Tainter jointly invented a wireless telephone, named a photophone, which allowed for the transmission of both sounds and normal human conversations on a beam of light. Both men later became full associates in the Volta Laboratory Association.
What did Bell call his cord-free phone? {sep_token} Who did Bell invent the cord-free phone with? {sep_token} What did Bell's cord-free phone use to transmit messages? {sep_token} What lab association did Bell and Tainter both eventually join? {sep_token} In the photophone, light carried sound and what? {sep_token}