InhaltsangabeMotivation and Introduction.- Quality of Human-Machine Interaction over the Phone.- Assessment and Evaluation Methods.- Speech Recognition Performance over the Phone.- Quality of Synthesized Speech over the Phone.- Quality of Spoken Dialogue Systems.- Final Conclusions and Outlook.- Appendices: A. Definition of Interaction Parameters.-B. Template Sentences for Synthesis Evaluation, Exp. 5.1 and 5.2.- C. BoRIS Dialogue Structure.- D. Instructions and Scenarios.- E. Questionnaires.