An expandable cage assembly has cage connecting insert assemblies. The air valve mechanism may comprise a single valve system that replaces the two valve system found in conventional air operated double diaphragm pumps. Upon reception of a paging message, If the terminal recognizes the service option contained within the paging message, the terminal then retreives a call termination alert tone corresponding to the recognized service option and generates the call termination alert tone. When the first voltage supply unit becomes incapable of supplying voltage to the memory, the memory is controlled to erase the data stored therein using a selected one of a plurality of erasing processes depending on the status of processing of the data. The device can sense violations to its components and includes an expiry time control. The balance weights are made of U-shaped, bent weight clips made of spring-elastic material, having at least two opposite clip legs extending parallel to each other which are connected to each other via a bend section, and comprise a clamping gap between the clip legs.