a timeslot assigning circuit for use in a ucol - type star network includes a first circuit block having a ram - type memory for storing incoming requests for assignment . the first circuit block is connected to a second circuit block , which includes a fifo memory in which requests for assignment are cyclically loaded . a decrementing circuit is connected downstream from the fifo memory , and a filter is connected at the input of the fifo memory and downstream on the decrementing circuit , so that requests for assignment which are null or are already satisfied are eliminated . a control circuit permits the cyclic scanning of requests , while a second fifo memory is provided at the output of the first fifo memory to contain the requests relative to single slots assigned during an operating cycle .