TTY (Teletypewriter) is a device that allows users to send typed messages across phone lines. Many people who are Deaf, deafened, hard of hearing, or who are deafblind may use TTYs to call other individuals.

What is the purpose of video relay service?

Video Relay Service is a form of Telecommunications Relay Service that enables persons with hearing disabilities who use American Sign Language to communicate with voice telephone users through video equipment, rather than through typed text.

What is video phone system?

videophone, also called video telephone, device that simultaneously transmits and receives both audio and video signals over telephone lines. … Frequently, the video camera in such a system may focus on either individuals or the group, often under control of the local user or under remote control of the distant party.