A roll control device includes at least one actuator having first and second chambers. The technique may be realized as a method for transferring information in a passive optical network having a plurality of network nodes. The first ripple harmonic is an integer multiple of the fundamental frequency component. By one approach, these subscriptions may also relate to offering civilly-catastrophic event-based access to one or more life-enhancing medical services. Also a recording medium contains a computer program for controlling the file data retrieving device. The pad group includes: at least one first pad provided with a first via-connection part electrically connected therewith and extended in a first direction perpendicular to a row direction of the pad row; and at least one second pad provided with a second via-connection part electrically connected therewith and extended in a second direction opposite to the first direction.