Protocol scope and method
The output names common standardized bits and preserves unknown set bits by their bit number.
Set flags = every bit i where alarmWord & (1 << i) is nonzero.
Diagnostic scenario
Copy the four-byte alarm word from a validated location body and compare the listed set bits with the platform event record. Test a single known bit and a multi-bit word so bit order, byte order and hexadecimal input handling are verified independently.
How to interpret the result
The decoder names common flags and preserves unknown bits numerically. A set bit describes the terminal report, not whether the alarm is active after platform confirmation, and edition or regional profiles may assign additional meaning.
Input reference
- Alarm word (hex)
- Example default: Sample input included
Common mistakes
- Using an unredacted production capture with vehicle, credential or network identifiers.
- Reversing the four bytes before applying the documented bit mask.
- Treating a successfully parsed sample as standards compliance or interoperability proof.
Before using the result
- Confirm the protocol edition, transport framing and vendor profile before interpreting fields.
- Compare one-bit test vectors with the selected edition table.
- Keep a redacted known-good and known-bad sample as a regression pair.
Questions to check during diagnosis
Does the JT/T 808 Alarm Flag Decoder leave my browser?
No application upload is used. Avoid putting sensitive production data in shareable URLs.
Is this a standards compliance test?
No. Confirm the edition and vendor profile with licensed documents and your target platform.
Offline diagnostic aid. Verify fields, version and vendor extensions before production use.