This read-only integer between 100 and 200 identifies the specific type of trap associated with a raised alarm. Because this numeric code maps to a specific condition in the vendor's documentation, an NMS can use it to automatically classify and route incoming alarms without a human having to interpret free-text descriptions each time. For example, seeing the same stuAlmTrapId value recurring across many STUs would let an operator quickly recognize a network-wide condition rather than treating each occurrence as an isolated unit problem.