Differential measurements allow correction of fixed-pattern noise errors in digital imaging arrays which use time-to-threshold AD conversion techniques. The side walls are interconnected by a plurality of support ribs. The contacts and shells may be formed with planar conductors aligned parallel to one another with a center conductive strip sandwiched between planar ground strips, all of which are separated by dielectric materials. The fluid-collecting lip is provided with an upper, thin edge at a radially retracted position relative to the outside surface of the wall of the container. The device may further detect cessation of the failure of the backhaul network; and resume, based on the detected cessation of the failure of the backhaul network, the communication sessions with the mobile devices.