Abstract: In an eye-directed communications device which displays characters, for example symbols or letters, and determines a user's selection by monitoring eye position to determine which of the characters is being observed, difficulties in providing for selection of the usual characters and functions of a conventional 101 key computer keyboard are overcome by dividing the required characters/functions into three sets, designated as lower case, upper case and "command" case. In order to select a particular character, the user first selects the case and then selects the character. Only one set need be displayed to the user, the characters in the other sets having spatial correspondence with those in displayed set. The system may also, or alternatively, display the characters in groups and define position selection fields corresponding to the positions of the characters in each group.

Abstract: A communication system for connecting a telephone switching office to a data processing center is described. A telephone trunk line from the switching office carries data which is digitally encoded and may be in a compressed format, for example mu-law PCM, and which is derived from remote data terminals. A novel type of modem is connected between the trunk and the data processing center. This is a direct synthesis device which converts the modulated digital data directly to a non-modulated digital format readable by the data processing center and, for digital data originating at the data processing center, produces modulated digital data which is transmitted along the trunk to the switching office. The direct synthesis modem is a single, purely digital device which replaces many separate digital/analog modems which are required in conventional systems.

Abstract: An eye-position sensor for use in an eye-activated optical transducer in which a spatial filter is used to modify light reflected from the eye to form a substantially rectangular pattern on a quadrantal array of contiguous sensors. This arrangement provides a substantially linear change in the output signal from the sensors in response to an equivalent movement of the eye.