I think the announcement is different from operator to operator. And you should give us more details in what case the announcements are coming. For example, if you make a outgoing call (MOC) and you get the announcement “SUBSCRIBERS NOT REACHABLE” => MS may be in implicit detached status. If “SWITCHED OFF” => MS in explicit detached status. Other announcements (“NETWORK BUSY”,”OUT OF COVERAGE AREA”) in what circumstance?