Data link

Datalink uses UHF and VHF radio to provide digital data communications with other users that have an IDM (Improved Data Modem). The IDM converts digital data to audio data for UHF or VHF radio transmission. When data is received from other users, the IDM converts the audio data to digital data and sends it to the avionics system for display in the cockpit.
Datalink must not be confused with the link 16.

Learning objectives

1. Understand how to pre-brief IDM
2. Host a datalink session
3. Enter IDM information in the DED
4. Understand cursor data vs. mark point data
5. Recognize HSD symbology for datalink

General information

Introduction

Datalink allows the flight lead and his wingmen increased situational awareness (SA), the ability to pass positional information about each jet in the flight to all flight members, to target flight members on to air-to-air or air-to-ground targets, to easily execute tactics that go beyond the visual arena and regain visual mutual support should a flight member become a “lost wingman”.
The DL system allows up to 8 IDM equipped aircraft to transmit and receive intraflight data link messages.

Modes of operations

Demand Mode Operation

The Demand (DMD) and Assign (ASGN) data link modes allow a team member to obtain a “one-shot” team situational awareness update (an intraflight transmission round) on an “as needed” basis.
The DMD and ASGN modes also enable the option to make assignments to other flight members.
The messages transmitted allow each member to see the positions and headings of other members and their bugged target on the HSD page and FCR page
Beware : Both A-A Request and A-A Reply messages are snapshots in time. Reply messages are extrapolated for 8 seconds. Once this extrapolation period ends, the symbols will disappear.

Continuous Mode Operation

The Continuous (CONT) mode allows the pilot to request continuous update of request and reply intraflight messages. This is the mode that also requires coordination amongst flight members if you are flying in the multiplayer environment, as only one aircraft needs to be in CONT mode and initiates the CONT data link round.

IDM Cockpit (DED) Initialization

DL Initialization

In order to effectively exchange information, each participating data link user must have compatible parameters initialized into his respective IDM terminal. In BMS, initialization parameters are automatically fed into the IDM – to an extent. Ownship team address numbers and other flight member team addresses are done for you. These addresses are for your (up to 4) intraflight members.
The additional team addresses 5-8 are not filled in and must be keyed in manually, based on the pilot’s needs or a package commander’s needs.
For example, you are 2-ship of DCA and the first flight of a package that has 4 flights in total. You are addresses 11-12; already in the left column. You decide that you want to maintain situational awareness primarily on the flight leads of the other flights. You can enter 21, 31, and 41 in the IDM and receive their positions on the HSD, or you can enter 2 of those addresses in the left column and also receive information on any radar contacts they lock up.

As seen in the picture on the right, LIST → ENTR gets the pilot to the A-G DL page.
The only two selectable options in this page are the Transmit Address (XMT) and the FILL option.
The FILL option determines whether the system stores (ALL) or ignores (NONE) all received data link steerpoints (71-80).

• When ALL is selected (default), the system will store the first message in STPT 71 and fill each subsequent STPT until it hits 80, upon which it will wrap around to the oldest location (71) and overwrite the data.
• When NONE is selected, no HUD or VMU (Voice Message Unit) messages are provided for these messages.
  

In most cases, FILL ALL is used. The FILL option has no impact on A-A intraflight or A-G cursor messages – they will be processed normally.
Sequencing right (SEQ) changes to the INTRAFLIGHT page, where up to 7 team addresses can be reviewed and changed (ownship address cannot be changed in BMS).

Important considerations for fraggers and Package/Flight leaders

There are a few last considerations you need to know about the IDM system in BMS.
During mission planning/ mission building, when you are building a package of aircraft, the first flight (in this case a 4-ship) in a package will be assigned addresses 11-14. The next flight will be 21-24 and so on.
If during planning you adjust takeoff times so that, for example, the first flight you created takes off later than another flight in the package, the first flight you created will still use addresses 11-14.
This is important because your IDM addresses may be different than what you thought they were going to be.
If you were not familiar with the order in which the flights within the package were created. A good technique is to check the order of the flights in your package on the Briefing page in UI before you commit to 3D.
It will list them in order. This can help you select the right transmit addresses for other flight in your package (if there are several flights in the package and you want to monitor the location of any of those flights).

Hosting data

• Host flight 1 player = CONT; COMM Switch Left - IFF Out LONG to start hosting data link
• all other players = DMD
• designate DL back-up flight
• Assign IDM in briefing like AA tacan assignments

Useful controls

HOTAS	ACTION
TQS: COMMS Switch Left - IFF OUT	Initiates A/A datalink (if held 1/2 sec or more) - Declutter FCR datalink symbols (if held less than 1/2 sec) The display will remain decluttered until Comms switch is toggled again for less than 1/2 sec.
TQS: COMMS Switch Right - IFF IN	Datalink AG FCR cursor position if FCR is SOI - Datalink currently selected groundpoint is HSD is SOI (steerpoint, markpoint etc ...)

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