Protocol scope and method
The lookup contains a conservative set of commonly implemented IDs. Unknown or edition-specific IDs remain unlabeled.
message group = high byte; exact name = maintained lookup table.
Common questions
Does the JT/T 809 Message ID Lookup 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.