This read-only object reflects the actual state of the BUS, which may differ from busAdminStatus, and the description gives the specific example that this can occur when the interface's ifOperStatus is down but busAdminStatus remains active. This is the object that reveals a real fault rather than administrative intent, since the description's own example is the underlying physical ATM interface going down while an operator still wants the BUS active, so a mismatch between this and busAdminStatus specifically points to an interface-layer problem, not a configuration mistake. busAdminStatus showing active while this object reads inactive is the direct signal that the physical ATM interface underneath the BUS has gone down, even if no one has changed the BUS configuration itself.