# Tactical data link

A tactical data link (TDL) uses a data link standard in order to provide communication via radio waves or cable. NATO nations use a variety of TDL standards. All military C3 systems use standardized TDL to transmit, relay and receive tactical data.
Multi-TDL network (MTN) refers to the network of similar and dissimilar TDLs integrated through gateways, translators, and correlators to bring the common tactical picture and/or common operational picture together.

## Change of terminology

The term tactical digital information link (TADIL) was made obsolete (per DISA guidance) and is now more commonly seen as tactical data link (TDL).

## Tactical data link character

TDLs are characterized by their standard message and transmission formats. This is usually written as <Message Format>/<Transmission Format>.

## TDL standards in NATO

In NATO, tactical data link standards are being developed by the Data Link Working Group (DLWG) of the Information Systems Sub-Committee (ISSC) in line with the appropriate STANAG.
In NATO, there exist tactical data link standards as follows:
Synopsis of TDL links :
| Link No | STANAG | Working Title | Final title / description | Communi- cation | Gene- ration | Comments |
| 1 | 5501 | NATO data link between Air Defence Main Control Centres | Link 1 – Tactical Data Exchange for Air Defence | Point-to-point | 1st S–Series | Ground Link between NADGE entities limited and not secure |
| 2 | | Radar to Control Centre Data Link | | | 1st | Cancelled (includes in Link 1) |
| 3 | | Control Centre to higher HQ Data Links | SHOC Early Warning System | Point-to-point | 1st | Slow Speed Warning Link from evaluation centres to SHAPE |
| 4 | 5504 | Ground to Air Data Link | Link 4 – TDL for the Control of Military aircraft | Point-to-point | 1st C/R–Series | Compatible to US TADIL–C to be operated in NATO UHF (225–400 MHz) RF band |
| 5 | | Fast HF Automatic Link | Broadcast | | 1st | Cancelled (see Link 11) |
| 6 | 5506 (Draft) | Missile Base to Control Centre Link | Link 6 – (NADGE Link) SAM Automatic Data Link | Point-to-point | 1st | Draft STANAG (US MBDL, ATDL–1, PADIL) |
| 7 | 5507 (Draft) | ATC / Defence Link | Link 7 – TDL for ATC | Point-to-point | 1st | |
| 8 | | HF Automatic Link | | Broadcast | 1st | Cancelled (see Link 1) |
| 9 | | SOC / Airbase Link | | | 1st | |
| 10 | 5510 | Ship – Ship Link | Link 10 – Maritime Tactical Data Exchange | Broadcast | 2nd M–Series | STANAG cancelled (was used by BE, NL and UK) |
| 11 | 5511 | Fast HF Automatic Link | Link 11 – Maritime Tactical Data Exchange | Broadcast | 2nd M–Series | Compatible to US TADIL–A to be operated in the HF & NATO UHF RF bands |
| 11B | 5511 (Vol. II) | | Link 11B – Tactical Data Exchange | Point-to-point | 2nd M–Series | Compatible to the US TADIL–B Ground to Ground TDL |
| 12 | | Fast HF Automatic Link | | | | Cancelled (see Link 11) |
| 13 | | HF Automatic Link | | Broadcast | | Cancelled (see Link 11) |
| 14 | 5514 | Slow Semi–Automatic Link | Link 14 – Maritime TDL | Broadcast | 1st D/M/S/E–Series | Ship–Ship & Ship–Shore (only few applications) |
| 15 | | Slow Semi–Automatic Link | | | | Ship–Ship, Cancelled |
| 16 | 5516 | High Capacity, ECM Resistant, Multifunctional, TDMA Link | Link 16 – ECM Resistant Tactical Data Exchange | Broadcast | 3rd J–Series | Compatible to US TADIL–J (STANAG 4175 – Technical Characteristics of MIDS) |
| 21 | 5521 (Draft) | Link in support of ACCS – (LISA) | | Point-to-point | 3rd J–Series | Under development (planned to replace Link 1 and Link 11B) |
| 22 | 5522 (Draft) | NATO Improved Link 11 – (NILE) | Link 22 | | 3rd J–Series | Under development (planned to replace Link 11) |
| | 5601 | Standard for Interface of Data Links 1, 11, 11B, and 14 through a buffer | | | | see AdalP 12 |
| | 5602 | Standard Interface for Multiple Platform Link Evaluation (SIMPLE) | | | | Enables transmission of J-Series (TADIL-J) messages over IP-based protocols |
| MIL-STD-6020 | 5616 | Standard for data forwarding between tactical data systems employing Links 11/11B and tactical data systems employing Link 16 | MIL-STD-6020, DoD Interoperability Standard: Data Forwarding between TDLs | | | |
| IJMS | | ECM Resistant Communication System (ERCS) | IJMS – Interim JTIDS/MIDS Message Specification | Broadcast | 2nd, M–Series | Interim Data Link Standard to be replaced by Link 16 |
| SADL | | Situational Awareness Data Link | SADL – Situational Awareness Data Link | Broadcast | 1st, K-Series 2nd, K/J–Series | Data link adopted from EPLRS to provide A-10s and F-16s data link capability air-to-ground and air-to-air |
Beyond NATO countries, NATO partner countries have also developed some degree of interoperability with these standards since the 2014 Partnership Interoperability Initiative.