Counter indicating change in the port alarm level. This is needed as rising or clearing of an port level alarm may not cause slotAlarmLevel to change. This counter, in such case helps a manager application to recognize that the alarm levels below slot level have changed without change in the slotAlarmLevel (e.g. Say: a line card has two subscriber lines experiencing Minor alarm condition. The slot alarm level will be minor alarm in such case. Now if one of the port level minor alarms clear, the port alarm level would become OK but slot alarm level will stay as a minor alarm. Alarm level change includes rising or clearing of a new alarm at slot/port level).