Link 16 J-series message list: J0–J31 labels, names and purposes

Link 16 J-series messages are the fixed-format binary messages (TADIL J) defined by MIL-STD-6016 and NATO STANAG 5516. Each one is named by a label from J0 to J31 and a sublabel from 0 to 7: J2.2 is Air PPLI, J3.2 is Air Track, J12.0 is Mission Assignment. The tables below list every publicly documented J-message with its name and purpose, grouped by function.

The list is built only from public sources and cross-checked between them: the US multi-service quick reference FM 6-24.8 (2000), the SISO-STD-002 Link 16 simulation standard and vendor training and product material. It is designed to be printed: use your browser’s print dialog or Save as PDF and the blog’s print stylesheet drops the navigation. For how the words are decoded and where codecs go wrong, read the companion Link 16 J-series field guide; for the waveform and terminals underneath, see what Link 16 is.

How to read a Link 16 J-series message label

A label such as J3.2 holds two numbers. The first is the 5-bit label (0–31), which names the message family — J3 is surveillance. The second is the 3-bit sublabel (0–7), which picks one message in that family: J3.2 is the air track, J3.3 the surface track. Both sit at the start of the message’s initial word, so a decoder knows which message it holds after the first ten bits.

Three more notations show up in specifications and logs:

• Word suffixes. An I, E or C after the label names one word of a message: J10.2I is the initial word of Engagement Status and J10.2C2 its continuation word 2.
• Parenthesized numbers. J28.2(0) is a specific message inside the J28.2 national label — here the Text Message used for free text.
• Gaps. Not every number is used. J4 and J18–J27 do not appear in the public catalogs, and J5 contributes a single message, J5.4.

The entry marked † appears in only one public source; confirm it against the standard revision your program uses.

J0–J8: network management, PPLI, surveillance and information management

These families keep the network running and build the shared picture: J0 and J1 manage the network, J2 lets every terminal report itself, J3 carries what sensors see, and J7 turns many independent reports into one consistent picture.

Network management (J0, J1)

Precise participant location and identification (J2)

Surveillance (J3)

Anti-submarine warfare, intelligence and information management (J5–J8)

J9–J17: weapons coordination, control, status and EW

These families make Link 16 a command channel rather than a picture feed. J11 was added for network-enabled weapons through a change to MIL-STD-6016C, so it is missing from the 2000 catalog; J16.0 and J17.0 appear in later vendor catalogs and gateway specifications.

Weapons coordination and management (J9–J11)

Control (J12)

Status, electronic warfare, threat warning, imagery and weather (J13–J17)

J28–J31: national use, free text and housekeeping

J28 sublabels are allocated to nations and services, which define their own content; the one most integrators meet is J28.2(0), the free-text message. J31 holds cryptographic housekeeping and the slot filler.

The J-messages a typical air picture depends on

A consumer that only needs the air picture — a C2 display, a fusion engine, a gateway feeding a COP — gets most of its value from a small subset. These are the messages to implement first:

Keep J2 and J3 apart. J2.2 is an aircraft on the net reporting itself; J3.2 is a track that a surveillance unit reports about something it observes, which may be hostile, unknown or a friendly without a terminal. Track identity in J3 combines environment, identity, platform, activity, specific type and nationality, and track quality runs from 0 to 15.

J-series message structure: words, bits and time slots

Every J-message is built from 75-bit words: 70 data bits plus 5 parity bits. The initial word opens the message with a 2-bit word format code, the 5-bit label, the 3-bit sublabel, a 3-bit message length indicator (MLI) and 57 bits of fields. Extension words add 68 bits of fields; continuation words carry their own 5-bit continuation label and 63 bits of fields. Each slot opens with a 35-bit header word naming the slot type and the sender’s source track number.

The packing chosen for a slot decides how many words it carries: 3 in standard double pulse, 6 in packed-2 single or double pulse, 12 in packed-4 single pulse. Packed and single-pulse formats trade anti-jam margin for capacity, and the header always goes double pulse. On the air, each 75-bit word is fifteen 5-bit symbols; a three-word data block is protected as three (31,15) Reed–Solomon codewords — 93 symbols, one per pulse — while the 35-bit header is coded as a (16,7) codeword. With 128 slots per second, the ceiling is 1,536 J-words per second; terminals pad unused positions with J31.7.

Link 16 message types beyond the J-series

“Link 16 messages” covers more than the J-catalog. A terminal handles six kinds of traffic:

VMF over Link 16 carries the K-series messages described in our Variable Message Format guide. RTT messages sit outside the J-numbering but matter to anyone simulating net entry.

Which NPG carries which J-messages

Link 16 time slots are allocated to network participation groups (NPGs), each defined by function — so the NPG also determines which messages travel on it. The joint assignments below follow FM 6-24.8; an operation’s OPTASK LINK is authoritative, and the Link 16 network design guide shows how slots are budgeted.

Two details trip up integrators. Air control (J12) has its own NPG 9, separate from weapons coordination on NPG 18. Forwarded PPLI (J2.0) rides NPG 14 for the US Navy but NPG 7 for the US Air Force and Marine Corps.

How software uses the J-series list

Codecs. A decoder reads the label and sublabel from the initial word, looks them up in a dispatch table and hands the words to that message’s field parser. The length indicator tells it how many words belong to the message, so unimplemented messages can be skipped without losing alignment. Generate the parsers from the controlling MIL-STD-6016 tables rather than by hand; the field guide covers spare bits, “no statement” values and test vectors.

Filters. Label-level filtering is the cheapest way to cut load: a COP may need only J2, J3 and J7. Planners pass transmit and line filters in the OPTASK LINK, and J7.6 Filter Management adjusts filters over the link.

Gateways. Translation is a semantic mapping, not a re-encode. FM 6-24.8 notes that when a US Navy shipboard C2P translated J-series into Link 11 and Link 4A messages, the expanded content and precision of J-series were lost, and one J-message could become as many as eight legacy messages — the trade-offs are compared in Link 11 vs Link 16 vs Link 22. Link 22 has its own catalog (see what Link 22 is), so a Link 16 to Link 22 gateway maps message by message, as does a bridge to TAK, where J2 and J3 tracks become Cursor on Target events. Our overview of tactical data link gateway software covers JREAP, VMF and NFFI bridges.

Link 16 J-series messages PDF and official sources

The authoritative definitions — field layouts, transmit and receive rules, every bit of every word — are in MIL-STD-6016 (Tactical Data Link 16 Message Standard) and STANAG 5516 (Tactical Data Exchange – Link 16). Neither is a public download; access runs through government and NATO channels, and our STANAG 5516 explainer covers the revisions. Every public list, this one included, is a summary for navigation.

The most complete public list is Figure I-3 of FM 6-24.8, approved for public release in 2000 — before J11, J16 and J17. SISO-STD-002-2021 publishes the header and word layouts and names MIL-STD-6016C through F and STANAG 5516 editions 3 to 6 as versions in use. To keep this list offline, print the page and choose Save as PDF.