Can a PSAP dedicate a separate seven-digit line for TTY calls?
Yes, but TTY users must also have direct, equal access to all call-taking positions on 9-1-1 lines. A PSAP cannot require TTY users to call a seven-digit number when voice callers may dial the more familiar 9-1-1. B. TTYs & Telephone Relay Services A TTY is a device that is used in conjunction with a telephone to communicate with persons who are deaf, who are hard of hearing, or who have speech impairments, by typing and reading text. To communicate by TTY, a person types his or her conversation, which is read on a TTY display by the person who receives the call. Both parties must have TTYs to communicate. When typing on a TTY, each letter is transmitted by an electronic code called Baudot, which is sent from the TTY on the sending end of the call through the telephone line in the form of tones to the TTY on the receiving end of the call, the same way voiced communications occur between two parties. The receiving TTY transforms the tones back to letters on a small display screen. Commu
