A scanner is connected to a G bus and a B bus by way of a scanner controller and a G bus/B bus interface (GBI). A printer is connected in a similar manner. Furthermore, the scanner controller is connected directly to a printer controller with a CP bus. The GBI is capable of performing DMA transfer and...http://www.google.com.hk/patents/US6707569?utm_source=gb-gplus-share專利 US6707569 - Image input/output control system
