A bus has a first set of data lines and a second set of data lines. The winding mechanism and method operates so that the winding needle does not have to enter to the bottom of the slots between the pole teeth but the wire is wound around the pole teeth from one end thereof with an arrangement for causing the windings to progressively move down the pole teeth as the winding continues. A cord having a plurality of stoppers is coupled to the tube. The actuating device is operatively connected to the screen and capable of actuating the screen to rotate 180 degrees in response to movement of the display module from a closed position to an open position with respect to the main module.