According to the IEC 60870-5-103 standard the disturbance recorder tags (digital signals) are identified by the same function type/information number combination that corresponds to the signal in the normal IEC 60870-5-103 Class 1 event transfer. This rule is followed by the IED if the indication signal in question is solely connected to the disturbance recorder digital channel. If the signal, for example, is OR-ed together with other internal digital signals or if the signal is not present in the normal IEC 60870-5-103 Class 1 data, then the tag identification is always:
Function type = 5
Information number = disturbance recorder digital channel number
Note: Tags are always sent in digital channel order.