A method of signaling resource allocation data in a communication system which uses a plurality of sub-carriers arranged in a sequence of chunks includes receiving an allocation of the sub-carriers for each of a plurality of user devices. The camera also has a compact housing which, in combination with the adjustable directionality of the turret, enables universal mounting to various structures and positions in an aircraft cabin. Such special purpose editors handle the single element to which they are attached and may handle a hierarchy of elements that share common properties in the subtree headed by the single element.