Evaluation of text telephones designed for people with impaired hearing or speech

The primary aim of this study was to assess a range of desktop text telephones and to provide comparative data to enable healthcare professionals and users to make informed choices when selecting products. Our second objective was to highlight the effect of different product features on ease of communication.

We used three methods of evaluation. (1) User trials of seven desktop textphones were carried out by 28 people. (2) The same desktop textphones, along with three portable models, were appraised by two independent assessors. (3) All 10 products were discussed by groups of hearing and hearing-impaired users-112 in all.

Participant ratings, user comments, and observations of sample conversations all revealed that ease of communication was greatly influenced by the type of technology employed to connect the textphone to the telephone network. Overall, conversations held on text telephones with a direct connection were more successful and produced fewer garbled messages than those made with an acoustic connection. Although individual preferences were expressed, other defining features such as the size of keyboard, display type and size of text did not have a comparable impact on communication. Future research and development could focus on the design of products that would cater simultaneously for the communication needs of hearing, deaf and speech-impaired users.