Link 16/MIDS Frequently Asked Questions

General Terminal Questions

  1. What is Link 16?
  2. What does MIDS-LVT stand for?
  3. What is a Block Cycle Upgrade?
  4. What is a Block Upgrade?
  5. What is a FOM? What is a FIM?
  6. The LVT(1) terminal does not seem to respond to any FIMs sent via Platform D. We have RARP server configured and the terminal will respond to PING requests at the supplied IP address. What's going on?
  7. What is the IP Address for a LVT(1) terminal?
  8. What are the Ethernet-based interfaces for MIDS-LVT?
  9. How does the LVT(1) terminal know whether to use the 1553 host bus or the Ethernet host interface?
  10. Is the MIDS-LVT capable of Link 16 voice?
  11. Can the MIDS-LVT be used for Link 16 Satellite Communications?
  12. What is MIL-STD-1553B?
  13. What is the support port?
  14. How do I access the support port?
  15. What is the IP Address for the support port?
  16. What is an LVT(3)? What is FDL?
  17. What is MIDS on Ship (MOS)?
  18. What is TACAN used for?

MIDS-LVT(2)

  1. What is the IP Address for a LVT(2) terminal?
  2. The default IP address for a LVT(2) terminal does not work in the addressing schema for our planned installation. How do I change the address?
  3. Can the LVT(2) terminal be configured to use RARP like the LVT(1)?
  4. What is the current draw of the LVT(2) terminal?

MIDS JTRS

  1. What is MIDS JTRS?
  2. Does the MIDS JTRS require a new set of cables?
  3. Does MIDS JTRS use the same RPS as the MIDS-LVT?
  4. Does MIDS JTRS have the same Ethernet and Support Port capabilities as MIDS-LVT?
  5. Does MIDS JTRS require a new mounting rack?
  6. Will my current MIDS-LVT host work as a host for MIDS JTRS?

Documentation Questions

  1. My LVT(1) terminal was delivered without any cables.  I can’t even turn it on.  Where can I find the specifications for the cabling?
  2. My LVT(2) terminal was delivered without any documentation.  Where can I obtain a tech manual or operator’s manual?
  3. Where can I learn more about Link 16?

Integration Questions

  1. I’m mounting the terminal in a transport case.  What do I need to consider?
  2. Do you have any suggestions regarding the power distribution in a rack installation?
  3. My LVT(11) came with a voice cable, but what does this connect to?
  4. Some of the items I need to use my terminal have a long lead time.  This will have an adverse impact on my schedule.  What can I do?

Power and Grounding Questions

  1. Are there any batteries associated with the MIDS terminal?
  2. How long will the MIDS batteries last?
  3. The MIDS batteries look like standard C Cell batteries. Can I substitute C cell batteries if I don’t have any of the U10025 batteries?
  4. What size primary power circuit breaker is recommended for the LVT(2)/(11)?
  5. Can I operate the LVT(2) on AC and DC power simultaneously?
  6. Should I ground the MIDS chassis?
  7. What's the difference between a Low Pass Filter and a Switched Notch Filters?

Antenna Questions

  1. I’m only using one antenna. What should I do about the antenna that’s not being used?
  2. What type of RF cable is normally used between the MIDS terminal and the antenna?
  3. I only have 100 feet of RG-214 cable and I want to use this between the MIDS terminal and my antenna. Will this be OK to use?
  4. We have an AS-4400 JTIDS antenna. Can this antenna be used for MIDS?

Operation Questions

  1. My LVT(1) terminal was turned Off, but I saw sparks when I disconnected J12.  What’s going on?
  2. When I start net entry with my MIDS terminal, crypto keys are dropped. What could be the problem?

Logistic Questions

  1. Can I ship the MIDS terminal myself or do I have to go through the CMS custodian?
  2. Will opening the MIDS terminal void the warranty?

Support Equipment Questions

  1. I saw you offer a host called LEGS. What is LEGS?
  2. Can LEGS simulate an F-16 MMC?
  3. I saw you offer a MIDS Flight Recorder.  How much data can I record from the terminal over the support port using this recorder?  How large is it?  How durable is it?

 


 

General Terminal Questions

Q    What does MIDS-LVT stand for?

There are two families of MIDS-LVT terminals – the LVT(1) family and the LVT(2) family.

The MIDS-LVT(1) family is the airborne terminal (although it is also used by ground units) and the system integrator must provide power, cooling, control, and cabling.

  • The LVT(1) implements TACAN and Voice. 
  • The LVT(4) eliminates TACAN. 
  • The LVT(6) eliminates Voice. 
  • The LVT(7) eliminates both TACAN and Voice.

The MIDS-LVT(2) family is the ground terminal (although it is also used by airborne units).  The LVT(2) family does not implement TACAN and includes power, cooling, control, and cabling.

  • The LVT(2) does not implement Voice.
  • The LVT(11) does implement Voice.

Q    What is a Block Cycle Upgrade?

A Block Cycle Upgrade is software upgrades to the government furnished CORE and TIO software and is controlled by the MIDS IPO.



Q    What is a Block Upgrade?

A Block Upgrade is a software package upgrade to the MIDS terminal containing the Vendor furnished software.  A Block Upgrade may also include hardware changes.



Q    What is a FOM? What is a FIM?

A FOM or Functional Output Message is a Terminal-to-Host communication transmission on the host bus.  A FIM, or Functional Input Message, is a Host-to-Terminal communication transmission on the host bus.  MIDS uses FIMs and FOMs rather than the Terminal Input Messages and Terminal Output Messages (TIMs and TOMs) employed by JTIDS terminals.



Q    The LVT(1) terminal does not seem to respond to any FIMs sent via Platform D. We have RARP server configured and the terminal will respond to PING requests at the supplied IP address. What's going on?

The terminal does not process any TCP packets that include options. By default, Microsoft Windows has TCP configured to use options. Please contact us for details.



Q    What is the IP Address for a LVT(1) terminal?

The LVT(1) terminal uses the Reverse Address Resolution Protocol (RARP) to obtain an IP address. Your network administrator will need to configure a RARP server to provide the terminal an IP address.



Q    What are the Ethernet-based interfaces for MIDS-LVT?

Platform-D for the LVT(1) family of terminals. Platform-J for the LVT(2) family of terminals.



Q    How does the LVT(1) terminal know whether to use the 1553 host bus or the Ethernet host interface?

There are jumpers in the host cable that identify to the terminal what type of host is connected.  These jumpers affect many of the settings such as the format of the data exchanged as well as voltage levels of the signaling.



Q    Is the MIDS-LVT capable of Link 16 voice?

Yes. The MIDS LVT provides two secure voice channels. The Voice Circuit Card supports both 16 kbps and 2.4 Kbps Voice selections.



Q    Can the MIDS-LVT be used for Link 16 Satellite Communications?

No, Satellite LINK 16 does not use the MIDS-LVT. It uses a host system to generate the J-series message to be encrypted and sent down to the SATCOM radio.



Q    What is MIL-STD-1553B?

MIL-STD-1553 is military standard published by the United States Department of Defense that defines the mechanical, electrical and functional characteristics of a serial data bus. It features a dual redundant balanced line physical layer, a (differential) network interface, time division multiplexing, half-duplex command/response protocol and up to 31 remote terminals (devices). Originally designed for use on aircraft, it can now be found on many military platforms. This is the standard bus that allows a host system to communicate with the MIDS-LVT(1) family of terminals.



Q    What is the support port?

The Support Port is an Ethernet interface of the terminal that provides access to detailed performance data, much of which is not available on the normal Host interface.



Q    How do I access the support port?

The Support Port is accessed through the host interface connector.  If this interface is not brought out in the host cable you are using, you can use Viasat’s Support Port Interceptor to gain access without affecting the existing cabling.



Q    What is the IP Address for the support port?

The terminal boots up with a default IP address. It also uses BOOTP to obtain an IP address. It is generally accepted practice to use a BOOTP server to change the support port IP address from the boot up default.  Contact us for details.

 

Q    What is an LVT(3)? What is FDL?

The LVT(3), or Fighter Data Link terminal as it is also called, is the 50-watt Link 16 terminal employed in the F-15.  The cards it uses are not interchangeable with those employed by the MIDS LVT(1) and LVT(2) families.



Q    What is MIDS on Ship (MOS)?

MOS is an LVT(1) terminal with software installed that implements the Class 2 JTIDS Navy Shipboard interface protocol.  It typically employs a High Power Amplifier.



Q    What is TACAN used for?

Tactical Air Navigation, or TACAN, is a military navigation system. It provides the user with a distance and bearing from a ground station. It operates with a channel spacing of 1 MHz in the frequency band 962 – 1213 MHz..

MIDS-LVT(2)

Q    What is the IP Address for a LVT(2) terminal?

LVT(2) terminals ship with a default IP address.  Please contact us for details.



Q    The default IP address for a LVT(2) terminal does not work in the addressing schema for our planned installation. How do I change the address?

Viasat has a LVT(2) configuration tool available. Please contact us for details.



Q    Can the LVT(2) terminal be configured to use RARP like the LVT(1) does?

Yes. This is a setting that can be changed using the Viasat LVT(2) configuration tool. Please contact us for details.

Q    What is the current draw of the LVT(2) terminal? I have two LVT(2) terminals with load files that are identical. One is registering ~7.4 Amps and the other is ~11.0. The terminal with ~7.4 amps has a low noise CU attached and the terminal with ~11.0 Amps has a high noise CU attached. Why are they different?

The low noise CU draws less current because the blower speed has been reduced.

MIDS JTRS

Q    What is MIDS JTRS?

The MIDS International Program Office has a product improvement program to migrate MIDS to a Joint Tactical Radio System (JTRS) implementing the software communications architecture.  This improved SCA-compliant radio is called MIDS JTRS.

The MIDS JTRS terminal is designed to operate using new communication protocols and perform new applications that will more easily integrate into more host platforms. In addition to Link 16 and TACAN functions, the MIDS JTRS includes three 2 MHz to 2 GHz programmable channels that allow the warfighter to use multiple JTRS approved waveforms, including the Wideband Networking Waveform (WNW). Improvements such as Link 16 enhanced throughput, Link 16 frequency re-mapping, and programmable crypto are also being realized in the MIDS JTRS design.



Q    Does the MIDS JTRS require a new set of cables?

MIDS JTRS is intended to be “plug and play” with MIDS-LVT, and most of the LVT(1) cables will also work with MIDS JTRS.  There are some differences, however, so please contact us for details.



Q    Does MIDS JTRS use the same RPS as the MIDS-LVT?

MIDS JTRS has its own Remote Power Supply.



Q    Does MIDS JTRS have the same Ethernet and Support Port capabilities as MIDS-LVT?

Yes and No.  MIDS JTRS implements Ethernet 10 Base T, whereas MIDS-LVT implements Ethernet AUI.  The current phase implements several 1553 host interfaces, but not the Ethernet host interface.  There is a Support Port and the data available on it is similar to that available from the MIDS-LVT.



Q    Does MIDS JTRS require a new mounting rack?

The Cooling Tray available from Viasat can be used with either MIDS-LVT or MIDS JTRS.



Q    Will my current MIDS-LVT host work as a host for MIDS JTRS?

There are some differences.  Contact us for details.

Documentation Questions

Q    My LVT(1) terminal was delivered without any cables.  I can’t even turn it on.  Where can I find the specifications for the cabling?

Refer to the MIDS hardware ICD.  You can obtain this document and other specifications from the MIDS International Program Office.  Contact Kenny Mohler by email at ken.mohler.ctr@navy.mil.



Q    My LVT(2) terminal was delivered without any documentation.  Where can I obtain a tech manual or operator’s manual?

There are 3 tech manuals maintained by the Army for the MIDS-LVT(2)/(11).  Contact Kenny Mohler at the MIDS International Program Office by email at ken.mohler.ctr@navy.mil.



Q    Where can I learn more about Link 16?

The USN/USMC and US Air Force have a series of guidebooks called Understanding Link 16. You can obtain copies from Northrop Grumman.  Contact george.pinkham@ngc.com.

Integration Questions

Q    I’m mounting the terminal in a transport case.  What do I need to consider?

The terminal has two air slots in the rear. The lower slot is the air inlet and the upper slot in the RFA chassis is the exhaust. 60% of the inlet air exhausts out the upper slot through the RFA and the remaining 40% is driven through the chassis shell (to cool the SRUs) and exhausts at the top and bottom of the front.  You want to avoid recirculating the warmed exhaust air in the rear immediately above the terminal. Recommend you allow 3" of space above the rear of the terminal for air circulation.  This can be accomplished, for example, by placing your equipment so that this area is not blocked. 



Q    Do you have any suggestions regarding the power distribution in a rack installation?

There are 350V applied to the terminal through J12 whenever primary power is on to the RPS.  This means there's voltage when the terminal is in the OFF state and you may experience arcs and sparks when removing the cable from J12. Recommend you provide an RPS primary power on/off switch.



Q    My LVT(11) came with a voice cable, but what does this connect to?

The LVT(11) voice cable connects to the H250 handset.



Q    Some of the items I need to use my terminal have a long lead time.  This will have an adverse impact on my schedule.  What can I do?

We carry many of the items needed to operate MIDS in inventory, including power, cooling, control, cables, bus couplers, batteries, filters, terminators, attenuators, 1553 cards, AUI transceivers, and more.  We may have the items you need in stock.

Power and Grounding Questions

Q    Are there any batteries associated with the MIDS terminal?

Yes, there are three 3.0V Lithium Manganese Dioxide circular batteries that are available from us or through the OEM (UltraLife Batteries Ltd. PN U10025). They are dark green in color with a polarity band marking the + terminal.  These batteries are classified as a USDOT class 9 hazardous material and may not be transported in passenger carrying aircraft. 



Q    How long will the MIDS batteries last?

Normal battery operation is 6-8 months and is dependent upon the amount of time the Terminal is placed and left in the Standby mode.



Q    The MIDS batteries look like standard C Cell batteries. Can I substitute C cell batteries if I don’t have any of the U10025 batteries?

Absolutely not. There are size and voltage differences which may render the MIDS terminal inoperable. We have these in stock under Viasat PN 1059074 (set of 3). Shippable by ground transport only.



Q    What size primary power circuit breaker is recommended for the LVT(2)/(11)?

For 115 VAC applications, a 20-amp breaker on an isolated non-GFCI circuit is required. For 28 VDC applications, a 40-amp circuit capacity is required (18-34 amps depending on time slot duty factor).



Q    Can I operate the LVT(2) on AC and DC power simultaneously?

Yes, the terminal load will share the two inputs and shift to AC or DC if one or the other is lost.



Q    Should I ground the MIDS chassis?

Yes. For safety reasons, all MIDS terminals must have a good Earth ground connected to the equipment chassis.



Q    What's the difference between a Filter and a Switched Notch Filter?

The Low Pass Filter (LPF) suppresses signals outside the MIDS band. Its purpose is to enable attenuation of undesired main terminal output signal components to levels such that no EMI is created. The MIDS ICD does not specify that an LPF is required, but it does describe it. The LPF suppresses the band above 1215 MHz as follows:

 

Cutoff: 3 dB down at 2 GHz.

5 to 14 GHz                      > 30 dB

14 to 20 GHz                    > 50 dB

These are available from Viasat under VPN 1031395 (for antenna A) and 1055529 (for antenna B).  Whether or not an LPF is required for the MIDS terminal is site-specific and must be determined by the system integrator.

A Switched Notch Filter (SNF) is typically used on aircraft installations and provides rejection at the 1030 and 1090 MHz bands. The SNFs are integrated with the aircraft Interference Blanker Unit (IBU). The IBU employs LVT1 discretes such as the Advanced Slot Notification and the TDMA and TACAN Suppression signals.  Here are the specifications for the SNF:

Minimum Passbands:

 

962-1012, 1048-1070, 1108-1215 MHz

Maximum -3 Dbc Stopband Points:

 

1008, 1053,1065,1110 MHz

Average Passband Loss:

 

1.7 dB Maximum. TACAN (Bypass)

Average Passband Loss:

 

3.3 dB Maximum. TDMA (Filter)

Maximum Passband VSWR:

 

1.6:1 (1.5 Typical)

Average Passband Group Delay:

 

17 nsec maximum

Stopbands:

 

1023-1037, 1083-1097

Minimum Stopband Rejection:

 

-46 dBc, 1023-1037, -43 dBc, 1083-1097

Maximum  TDMA Power Handling:

 

250 W Peak, 50 W average

Maximum   TACAN Power Handling:

 

400 W Peak, 4 W average

Temperature:

 

At Least -30 C TO +85 C

Operating Voltage:

 

+28 V, +5, -7% (100 mA)

Switching Speed:

 

1 microsec, maximum

Input Switching Rise/Fall Time:      

 

600 nS MAX.

Filter Status Output:

 

Open/Ground Discrete

(Normal Indication: Ground;  Failure: Open)

Switch Control Voltage:

 

Differential +2 TO +6V -2 TO -6V

These are available from Viasat under VPN 1031936.

Antenna Questions

Q    I’m only using one antenna. What should I do about the antenna that’s not being used?

As with all RF equipment, you need to terminate the unused antenna ports.  Recommend a 250W terminator or attenuator such as Weinschel 1433-3 or 1426-4.  We normally carry these in stock.



Q    What type of RF cable is normally used between the MIDS terminal and the antenna?

For antenna lengths that are 20 feet or less, RG-214/U is the recommended cable type. For distances greater than 20 feet, use heliax low loss cable. The specific size of heliax cable is dependent upon several installation criteria such as maximum length, wall protrusions and antenna supporting mast structure.



Q    I only have 100 feet of RG-214 cable and I want to use this between the MIDS terminal and my antenna. Will this be OK to use?

You can use RG-214 for a long run only if you can accept a significant reduction in communication range.  For 100 feet, the RF output at the antenna will be roughly 1/10th of the normal RF power available at the Terminal output. There will be an 8 dBm loss of signal both ways through this long antenna cable.  It is better to use low loss heliax cable for this long of a run.



Q    We have an AS-4400 JTIDS antenna. Can this antenna be used for MIDS?

Yes.

Operation Questions

Q    My LVT(1) terminal was turned Off, but I saw sparks when I disconnected J12.  What’s going on?

There are 350V applied to the terminal through J12 whenever primary power is on to the RPS.  This means there's voltage when the terminal is in the OFF state and you may experience arcs and sparks when removing the cable from J12. Recommend you provide an RPS primary power on/off switch.



Q    When I start net entry with my MIDS terminal, crypto keys are dropped. What could be the problem?

This is most likely an interconnecting cable issue. Call us for details.

Logistic Questions

Q    Can I ship the MIDS terminal myself or do I have to go through the CMS custodian?

Your CMS custodian will ship the MIDS terminal for you. Do not ship via normal shipping channels.



Q    Will opening the MIDS terminal void the warranty?

It depends on whether your agency is authorized to repair terminals.  Contact us if you are not sure.

Support Equipment Questions

Q    I saw you offer a host called LEGS. What is LEGS?

LEGS – Link 16 Environment Gateway Stimulator is a computer-based tool designed to support control, configuration & test of the Link 16 terminal. This tool implements all of the host interface types (1553, X.25, Ethernet) in order to communicate with the Link 16 terminal. 



Q    Can LEGS simulate an F-16 MMC?

LEGS can communicate with the MIDS terminal using the same protocol as an F-16 MMC. It can exercise the terminal in the same manner as several types of host systems by transmitting the correct FIMs and FOMs that each host would use to communicate with the terminal.



Q    I saw you offer a MIDS Flight Recorder.  How much data can I record from the terminal over the support port using this recorder?  How large is it?  How durable is it?

You can record as much data as the terminal is able to provide.  Even if every time slot contains Fixed Format messages at Packed-4, the 1 GB removable Compact Flash memory employed by the MFR will hold over 10 hours of recorded data. That’s a time slot duty factor of 172%. If only half of the slots are used at Packed-2, it will hold over 20 hours of recorded data.  The recorder measures about 5” x 6” x 2” and weighs about 3 lbs.  It meets the same altitude, shock, and vibration test requirements as the MIDS LVT(1).  It is very durable.  In fact, it continued to operate after the 40G shock test!