Ventus provides reliable data communication over unreliable half- or full-duplex transmission media. Ventus is a conditionally compliant implementation of the MIL-STD-188-220 Department of Defense Interface Standard for Digital Message Transfer Device (DMTD) Subsystems. Use of MIL-STD-188-220 facilitates interoperability with other DMTD systems.

Applicable Standards

  • MIL-STD-188-220B
  • MIL-STD-188-220C
  • MIL-STD-188-220D

U.S. Army - Improved Data Modem

Ventus is the MIL-STD-188-220 implementation for the U.S. Army IDM-304, IDM-304B, and IDM-401 platforms. Used by the IDM V9.1, V9.2, and V10.1 Operational Flight Programs, Ventus provides the next generation of IDM data link capability.

AH-64D, ARH-70A, CH-47F, OH-58D, UH-60M helicopter outlines


Used by the IDM, Ventus provides the MIL-STD-188-220 data link for the AH-64, ARH-70A, CH-47F, OH-58D, and UH-60M. Ventus is the most reliable Private Net solution.


Ventus supports the full range of MIL-STD-188-220, not just a subset. Whether you need connectionless or connection-oriented data links, high throughput or guaranteed network access, Ventus has you covered.


Built from the ground up for embedded systems, Ventus is memory-conservative and is light on system resources. Written in ANSI C, Ventus can be ported to nearly any platform.

Future Airborne

For integration into modern military systems, contact sales to ask how to use Ventus in a FACE-conformant Environment.


For JTRS radios, Ventus supports an SCA-compliant Intranet Layer, Data Link Layer, and Physical Protocol. Contact sales for more information, including IDL and configuration properties.


With more than 1200 tests covering every aspect of the system, you can be sure that Ventus meets every requirement. All of the testing is fully automated, and everything traces back to the DSPICS.

Technical Specifications

Protocol Versions

Ventus supports all active versions of MIL-STD-188-220:

  • MIL-STD-188-220B
  • MIL-STD-188-220C
  • MIL-STD-188-220D

Physical Layer Protocol

To facilitate integration with diverse radios, Ventus supports all of the physical layer interfaces:

  • Synchronous Mode
  • Asynchronous Mode
  • Packet Mode

Net Access Control

The timing and reliability characteristics of every network are different. That is why Ventus supports all six Network Access Delay (NAD) methods:

  • Random (R-NAD)
  • Probabilistic (P-NAD)
  • Hybrid (H-NAD)
  • Radio Embedded (RE-NAD)
  • Deterministic Adaptable Priority (DAP-NAD)
  • Data and Voice (DAV-NAD)

Types of Procedures

  • Type 1 - Unacknowledged Connectionless
  • Type 2 - Connection-mode
  • Type 3 - Acknowledged Connectionless
  • Type 4 - Decoupled Acknowledged Connectionless

Limit the types of procedures used on the network to one or two, or use the full range by specifying the Station Class:

  • Class A (Types 1, 3)
  • Class B (Types 1, 2, 3)
  • Class C (Types 1, 3, 4)
  • Class D (Types 1, 2, 3, 4)

Data Link Frame

  • Unnumbered (U), Information (I), and Supervisory (S) PDUs
  • Single-octet Addressing
  • Four-octet Addressing
  • Six-octet Addressing
  • Group Multicast Addressing
  • Global Multicast Addressing
  • Immediate Retransmission

Operational Parameters

All of the Type 1 operational parameters are supported, even the new MIL-STD-188-220D Unnumbered Frames:

  • Topology Update ID
  • CANTPRO Version Number
  • CANTPRO Preferred Version Number

Type 2 provides a connection-mode service when guaranteed reliability is paramount. Ventus supports all of the Type 2 operational parameters to maintain connections with multiple stations.

The Type 4 Identification Number and Duplication Frame Detection are supported to efficiently process messages sent with decoupled acknolwedgments.

Error Detection and Correction

  • Golay FEC
  • Time Dispersive Coding (TDC)
  • V.36 Data Link Scrambling

Intranet Protocol

Network Access Control (NAC)

The network timing model allows for granular control over every aspect of transmission and reception, from the Equipment Lag (ELAG) to DTE Turnaround Time (DTETURN).

Network timing is specified down to the millisecond, with discrete periods of time for Network Access Delay (NAD), Response Hold Delay (RHD), and Timeout Period for coupled acknowledgments.

Emission Control (EMCON) prohibits the transmission of any data on the network. EMCON Override allows the operator selective transmission when in EMCON.

Combat Net Radio (CNR) Management

Use CNR Managment to join a network without knowing the timing parameters. A network control station will let you know what to select and when to join.

All of the XNP message formats are supported:

  • Join Request
  • Join Accept
  • Join Reject
  • Hello Message
  • Goodbye Message
  • Parameter Update Request Message
  • Parameter Update Message
  • Delay Time Message
  • Status Notification Message

And all of the XNP data blocks are supported so you will always have the right configuration:

  • Station Identification
  • Basic Network Parameters
  • Configuration Parameters
  • Type 3 Parameters
  • Deterministic NAD Parameters
  • Probabilistic NAD Parameters
  • RE-NAD Parameters
  • Wait Time
  • Type 2 Parameters
  • Type 4 Parameters
  • NAD Ranking
  • Intranet Parameters
  • Error
  • Address Designation Parameters

Transmission Channel Interfaces

Because Ventus is a complete software solution, all of the transmission channel interfaces can be accomodated:

  • NRZ Interface
  • FSK Interface
  • CDP Interface
  • DPSK Interface
  • Packet Mode Interface
  • ASK Interface