Mode setting device in pocket or portable computers with data terminal function

Claim 1

A data termainal interface device that can be used in a external connection with a portable computer that has a display with a small capacity for displaying characters in only a single horizontal line and a keyboard, the portable computer being usable as a data terminal, comprising: means for causing the display of said computer to display data terminal control prompts so as to guide the operator in the use of the computer, whereby each prompt is arranged along said single horizontal line so that it is vertically aligned with a specific one of a plurality of function keys of the computer keyboard, said keys being disposed on a line parallel to the single horizontal line of the display and displaying said prompts on the display in accordance with a plurality of general formats whereby each format contains a plurlaity of specific mode setting capabilities of the computer; means for stepping the display from one of said general formats to another of said general formats without activating one of the keys that correspond to the display prompts; and means for stepping the display through the available specific modes within any selected one of said general formats by actuating a key which is vertically aligned with a prompt associated with the specific modes.