Thomas Edison worked on the two-way variant of this: https://www.atlasobscura.com/articles/dial-a-ghost-on-thomas-edisons-least-successful-invention-the-spirit-

Thomas Edison worked on the two-way variant of this: https://www.atlasobscura.com/articles/dial-a-ghost-on-thomas-edisons-least-successful-invention-the-spirit-phone https://www.atlasobscura.com/articles/dial-a-ghost-on-thomas...