Allows people who are hearing, hard-of-hearing, deaf, or speech impaired to make phone calls using one device
If the user cannot hear but wishes to speak, the other party's responses will display on the TTY (if both parties have an ATT-TTY8840, no relay service is necessary)
Conversations between the TTY and a person who does not have a TTY will go through a relay service, which is available in most areas
Sleek design with handset volume control
Keyboard
Voice carry over (allows you to speak into the handset while reading TTY responses)
10# Speed dial memory
Auto ID (alerts most 911 services that you are calling by a TTY)
TTY auto-answer (answers even when you are away and stores TTY messages
can also be used as a voice answering machine when auto-answer is turned off)
Conversation and auto-answer memory
48 Character, 2 line backlit LCD
Printer port
Built-in ring flasher
Personalized TTY greeting and auto-answer messages
Sticky keys
Turbo Code and Baudot compatible
Adjustable handset amplification
Redial
Flash (allows you to communicate with banking services and gives access to subscription services like call waiting)