There is an unmet need for a flexible telecommunications capability for the hearing-and speech-impaired. TDD service (telecommunication Devices for the Deaf) allows access to the public phone network for many who would otherwise have no access, but it has significant limitations. - TDD access and domain of service are limited by the scarcity of TDD terminals; - service capability is limited to typewritten messages. These limitations are self-reinforcing; they limit the attractiveness of TDD, which in turn reinforces the limitations. The TeleGraphics Device (TGD) was conceived to address TDD's limitations: It is a small graphics terminal to be used with any phone on a standard line, allowing concurrent voice and text/graphics interaction. The crux of TGD development is to have acceptable voice (quality) and graphic (rate) communication within the limited voice bandwidth of the public telephone network, in a way which does not require a TGD on both ends for normal telephone use. [That is, phones with TGD must be backward- compatible to phones without TGD.] Feasibility has been indicated by initial calculations and testing, and most of the hardware for a target implementation has been selected. The first phase in this project requires two units to demonstrate feasibility and test directions for implementation. Initial problems to be addressed for these prototype units are to refine the voice/data multiplexing scheme, to develop the write-on display screen and to couple this user interface with the voice/data multiplexer.
