Access to medical monitoring device service is controlled by inputting a set of identification data elements into a medical monitoring device system, which then establishes a communication link with a central unit and communicating the set of identification data elements to the central unit. When an MS registers with the network, the MS shall indicate as part of the early classmark process its location calculation capabilities and the type algorithm to be used for deciphering the network information. Since the coil is fixed in place by using air pressure, the coil can be fixed onto a patient bed without arranging any fixing structure on the patient bed, and therefore the coil can be positioned and fixed at any place on the patient bed for carrying out a scanning operation according to needs. One specific embodiment uses a die center piston and compressed air to apply force to the die center insert. Subsequently, in response to a proximally directed force, the tab is released from the abutment, it returns to a passive, unstressed configuration, and the guard moves to expose the needle for aspiration. The anti-mismating portion is capable of interfering with the contacting portion of the terminal when the cover is mounted to the insulating housing in a contrary way.