Abstract: A polling communication method which asks whether or not there is a request with data from a range of answer requesting terminals. A request is determined by a binary looking-up to terminals by a center. The center and the terminals are connected through a common signal transmission line, replying to the center that there is a request with a self-address to the requesting terminal. There is a further reducing of the range of answer requesting terminals by sequentially determining, according to a binary looking-up to specify one of the requesting terminals when a collision of the requests occurs between the terminals at the replying time. The center then asks the content of the request to the specified terminal. Thus, this method can process requests at a high speed, not only when the rate of requests of terminals is low but also when the rate of requests of terminals is high and often collide.