For a mail order application, the SPREIN voice control system has been developed and tested in a field trial. It consists of a dialogue and communications controller and several telephone conversation units (TCU). Each TCU contains a speaker independent isolated word recognizer, an unlimited vocabulary speech synthesizer and a tele- phone line interface. Ordering is done fully automatically using synthetic speech for user guidance and feedback. The device has been developed in 1986 to 1988, and has been evaluated by the German Telekom in 1988 to 1990. In off-line tests, the recognizer's average error rates improved from 2. 7% in 1988 to 1. 8% in 1990. A field trial with voluntary users revealed that the main weakness of the system Is its slow speed of data entry compared to keyboard entry or human order acceptance via telephone. In spite of its drawbacks, users accepted the system and wanted it to to stay on-line after the end of the field trial.
Bibliographic reference. Ruehl, Hans-Wilhelm (1991): "Voice controlled mail ordering via telephone using SPREIN", In EUROSPEECH-1991, 945-948.