An apparatus and method for the determination of the attitude of a remotely monitored device attached or non-attached to the body of a remotely monitored person is disclosed. The through-hole forming member is disposed openable with respect to the carriage. A standard registration message associated with each cell in the zone is modified, which modifying results in a modified registration message with a command that is directed towards instructing mobile stations that are already registered in the zone to re-register with the zone.