Abstract: In an optical ATM switching system, an optical ATM cell is produced in response to an incoming ATM cell so that it contains an optical routing bit in a timeslot corresponding to the destination of the cell. A first switching stage is provided for routing the cell from one of its inlets to one of its outlets in accordance with the routing bit contained in the cell and generating a routing signal indicative of the position of the outlet to which the cell is routed. A second switching stage is connected to the outlets of the first switching stage for routing the cell to one of optical buffers in response to the routing signal from the first switching stage. Optical combiners are provided, each corresponding to a group of the optical buffers for combining outputs of the corresponding group of optical combiners.

Abstract: A printing method using a photographic printer which effects at an identical or proximate position photometry conducted by dividing an image frame into a multiplicity of segments and exposure based on data obtained by photometry. The process of effecting both photometry, and selecting and storing data necessary for determination of exposure amount is repeated until the number of items of the data stored reaches a predetermined value or more. When the number of items of the data stored has reached the predetermined value or more, an image frame to be printed is positioned in an exposing position, and exposure is effected on the basis of photometric data on the image frame and the stored data.