TTY (Teletypewriter)

A TTY (Teletypewriter) is a device or application used to send or receive character by character communication using Baudot signaling.

a.k.a.

TDD (Telecommunications Device for the Deaf)

Direct Connect

A method of connecting a TTY directly into the phone line. When using direct connect, you can dial directly from the keyboard and use auto-answer features.

Integrated TTY

TTY functionality that has been integrated within a computer workstation. This may be found within the 9‑1‑1 telephony system or interfaced in a CAD (computer aided dispatch) system.


 * NENA-STA-027, E9-1-1 PSAP Equipment Standards
 * NENA-STA-010, Detailed Functional and Interface Standards for the NENA i3 Solution
 * APCO/NENA ANS 3.105.1-2015, Minimum Training Standard for TTY/TDD Use in the Public Safety Communications Center

[https://www.gallaudet.edu/about/history-and-traditions/tty-relays-and-closed-captions What’s a TTY? What’s a TDD? What’s a relay system?]