This attribute displays the Local Management Interface user side
procedure event history in order of occurrence. An event is
represented by a single symbol. A '+' symbol indicates a good
event. An 'X' symbol indicates a protocol error event. The left most
event is the most recent to occur. The provisioned eventCount
dictates the maximum number of events displayed. A good event is
triggered by receipt of a valid status message. An error event is
either a T391 timer expiry or receipt of a status message with an
incorrect sequence number.