A research model of a synergism between a telephone and a computer terminal is described in this paper and its companion. The hardware design of this “teleterminal,” described in the companion paper, includes an internal microprocessor and a data connection to a host computer. This paper describes the software in these two machines. The software resident in the teleterminal's internal microprocessor addresses internal issues like cursor control, tab expansion, and data modes. The software resident in the host controls screen content and menu selection. The teleterminal is a research tool for the investigation of the human interface for the access to experimental services. Such services include calling by name, directory retrieval, a variety of information (e.g., yellow pages, department store catalogs, community bulletin boards, newspapers, and libraries) and a variety of personal services such as mail, personal calendar, entertainment, and shopping. The user-interface is a conceptual tree-like structure that can be customized by the user.