A switching apparatus is disclosed that employs a relatively simple and inexpensive switching matrix, but which avoids interruption of existing connections when connections are added or removed. The switching matrix switches errorlessly by controlling the point in time at which switching occurs. Using...http://www.google.com.tw/patents/US6982974?utm_source=gb-gplus-share專利 US6982974 - Method and apparatus for a rearrangeably non-blocking switching matrix
