A Teletypewriter (TTY) Installer is a professional who installs and repairs telegraphic transmitting and receiving equipment. A teletypewriter is known as an electromechanical typewriter meant for point-to-point communication. According to the U.S. Bureau of Labor and Statistics https://www.fieldengineer.com/skills/teletypewriter-installer  a Teletypewriter Installer falls into the category of telecommunication equipment installer (telex).