Tactical data link

A tactical data link 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 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 was made obsolete and is now more commonly seen as tactical data link .

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 of the Information Systems Sub-Committee in line with the appropriate STANAG.
In NATO, there exist tactical data link standards as follows:

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
3		Control Centre to higher HQ Data Links	SHOC Early Warning System	Point-to-point	1st	Slow Speed Warning Link from evaluation centres to Supreme Headquarters [Allied Powers Europe\|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 RF band
5		Fast HF Automatic Link	Broadcast		1st	Cancelled
6	5506	Missile Base to Control Centre Link	Link 6 – SAM Automatic Data Link	Point-to-point	1st	Draft STANAG
7	5507	ATC / Defence Link	Link 7 – TDL for ATC	Point-to-point	1st
8		HF Automatic Link		Broadcast	1st	Cancelled
9		SOC / Airbase Link			1st
10	5510	Ship – Ship Link	Link 10 – Maritime Tactical Data Exchange	Broadcast	2nd M–Series	STANAG cancelled
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		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
13		HF Automatic Link		Broadcast		Cancelled
14	5514	Slow Semi–Automatic Link	Link 14 – Maritime TDL	Broadcast	1st D/M/S/E–Series	Ship–Ship & Ship–Shore
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
21	5521	Link in support of Air [Command and Control System\|ACCS] –		Point-to-point	3rd J–Series	Under development
22	5522	NATO Improved Link 11 –	Link 22		3rd J–Series	Under development
	5601	Standard for Interface of Data Links 1, 11, 11B, and 14 through a buffer				see AdalP 12
	5602	[SIMPLE \|Standard Interface for Multiple Platform Link Evaluation ]				Enables transmission of J-Series 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	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.