Reading Decoder Results – What Each Field Means

The grid uses the same three columns for every decoder, but what goes in them differs by type:

• ACARS — Id shows the aircraft’s registration (tail number); Info shows the message label and text.
• AIS — Id shows the vessel’s MMSI number; Info shows the vessel name (where known) plus position, speed, and course, or just the message type if no position was included.
• POCSAG — Id shows the capcode (RIC); Info shows the pager message text.
• RTTY — there’s no addressing concept in RTTY, so Id is always blank; Info shows the decoded text.
• DMR — Id shows the talkgroup (or source radio ID if no talkgroup is known); Info shows the call type and metadata (colour code, timeslot, source ID where available).

The CRC Column

This doesn’t mean the same thing for every decoder:

• ACARS and AIS show a genuine pass/fail integrity check — “OK” or “ERR.”
• POCSAG shows “OK” for a clean message, or “~” if the message needed error correction to be recovered.
• RTTY has no integrity check at all, so this column is always blank.
• DMR always shows “OK” — this isn’t a variable per-message check; DMR metadata is only ever surfaced once it’s already passed an internal integrity check, so nothing reaches this list without already qualifying.