A program to communicate with phone TTY/TDD devices (Telecommunications Devices for the Deaf) via a sound card, without TTY modem. A simple interface between sound card and phone line or acoustic connection with phone handset are used. Together with "Virtual Audio Cable" software CallTTY can work via Skype Internet-phone, without additional hardware at all.

CallTTY TDD software keywords: tty, tdd, baudot, deaf communications