A bolt-ring pipe connector system for connecting thermoplastic stub end pipe is shown. The message is dropped, and a counter is incremented to track a number of occurrences of receiving the message in response to detecting that the sequence number in the message is within the valid sequence number range. The loop filter converts this proportional current to a voltage and connects it to the oscillator input. All of the states in which a signal voltage is not present at precisely one signal input can be detected as faults, as a result of which short circuits and line interruptions can be detected. Features of candidate suspicious anomalies across images may be jointly evaluated to perform classification.