telephone device for the deaf (n)~ A device that enables the transmission of typed messages over phone lines. These devices typically include keyboards for typing messages to send and display and/or printers to receive messages from one device to another. telephone typewriter device (n)~ A device that enables the transmission of typed messages over phone lines. These devices typically include keyboards for typing messages to send and display and/or printers to receive messages from one device to another. Telephone User Interface (n)~ An interface that is used to navigate the menus of a Unified Messaging (UM) system using DTMF or touchtone inputs.