A reduction gear having a planetary gear set for reducing the output rotation speed of a motor, a counter gear set for reducing the output rotation speed of the planetary gear set, and a planetary gear set for reducing the output rotation speed of the counter gear set. An plurality of GI mode division signals are generated by processing the correlation signal delayed by different delays. A LED lighting module is turn-able to connect with the frame on which a module positioning unit is set to limit the rotation of LED lighting module. The system can therefore maintain files of a document under its original format and in a separate file under a universal format. At least one of the shaft and the coupler is preferably supported independently of the other and provided with crown involute splines, whereby one of the shaft and coupler when out of relative alignment, continues to drive the other without the necessity of adding additional moving parts to the drivetrain component. The at least one network page includes a concept list and at least a portion of a plurality of items.