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  • Introduction
  • A case for HF in the modern world
  • Interoperability Overview
    • Achieving HF Interoperability
    • HF HOUSE
    • MIL-STD
    • STANAG
  • HF and VHF/UHF Equipment
    • Product Families
    • Product Lifespan
    • NATO & MIL-STD Specifications Mapped to RapidM RM & RC Products
  • Test Systems and Profiles for Interoperability
    • NATO BRASS Overview
    • S5066/BRASS Test Systems & Profiles
    • S4691/MARLIN Test Systems & Profiles
    • S4591/MELPeTest Systems & Profiles
  • Test Equipment & Tools
  • Abbreviations and acronyms

NAVAL and STRATEGIC COMMUNICATIONS

By adopting standardised HF/VHF technology, countries with shared maritime interests and security commitments can achieve self-reliance for naval and strategic communication. Reliance on satellites or fixed infrastructure exposes critical operations to significant vulnerabilities.

Interoperability between nations is of the utmost importance and can be achieved by fielding NATO-standardised products in HF/VHF core systems. RapidM has well-established relationships with integrators in countries such as Italy, Sweden, Denmark, Spain, the United Kingdom, and France, and major navies are successfully using our equipment.

We are actively working on various broadcast, ship-to-shore, and tactical HF standardisation profiles and can offer expert advice on HF core system requirements. We have supplied numerous prominent Tier 1 naval platforms with standardised products and solutions, allowing for drone-proof distribution of shore stations in diverse, dispersed locations. The combination of NATO BRE2TA (BRASS Enhancement 2 Technical Architecture), MELPe NATO Voice, and STANAG 4538 achieves tactical HF interoperability. Dynamic networked IP data communication in multi-node, multi-hop V/UHF Line-of-Sight (LOS) and HF Extended Line-of-Sight (ELOS) radio circuit networks is emerging with STANAG 4691 (MARLIN).

In addition, we provide tactical products and solutions that allow amphibious forces and partner forces to achieve interoperability with shore stations using equipment already fielded.

Our high-end data modems, ALE controllers and ARQ protocol units offer exceptional levels of performance. Our products also fully comply with emerging and relevant industry standards, including ISO, IEC, CE and interoperability standards such as MIL-STD-188-110B and 110C; MIL-STD-188-141B, 141C and 141D; and STANAG 4538, 4539, 4539/TDMA, 5066, and 4691.

Our RM, RC, and RI product families enable beyond line-of-sight (BLOS) communications, secure data exchange, and supports point-to-point communication, ship-to-shore communication, ground-to-air communication, and broadcast transmissions.

Our products integrate into 19-inch rack-mounted configurations at high-power NATO shore stations and mobile platforms, supporting BRASS, BRE1TA, and BRIPES operations.

RapidM's naval and strategic product range provides reliable, long-range communication solutions for navies, coast guards, and commercial users, supporting various platforms and operations in both satellite and satellite-denied environments. Tactical data link platforms are supported, providing a communication backbone for both defence and commercial sectors.

OVERVIEW

Contents

  • Introduction
  • A case for HF in the modern world
  • Interoperability Overview
    • Achieving HF Interoperability
    • HF HOUSE
    • MIL-STD
    • STANAG
  • HF and VHF/UHF Equipment
    • Product Families
    • Product Lifespan
    • NATO & MIL-STD Specifications Mapped to RapidM RM & RC Products
  • Test Systems and Profiles for Interoperability
    • NATO BRASS Overview
    • S5066/BRASS Test Systems & Profiles
    • S4691/MARLIN Test Systems & Profiles
    • S4591/MELPeTest Systems & Profiles
  • Test Equipment & Tools
  • Abbreviations and acronyms

A case for HF in the modern world

Dependence on satellites or fixed infrastructure presents various operational vulnerabilities, which could make it challenging to achieve effective strategic communication. Radio communication offers a unique solution that is self-owned, self-controlled and less vulnerable to jamming and destruction. High-frequency (HF) backbone networks provide a critical beyond line-of-sight (BLOS) capability for navies and coast guards, enabling long-distance communication.

HF communication is a staple for use in remote areas and was the primary means of long-range communication before the launch of satellites. HF radio waves reflect off the ionosphere, a series of ionised layers high above the atmosphere, to provide beyond-line-of-sight communication. This form of propagation enables HF transmissions to be sent and received over hundreds or even thousands of kilometres, making it particularly well-suited for maritime applications.

Although inherent low data rates and potential eavesdropping pushed this technology to the backseat, HF is making a comeback with an infusion of new digital technology. Wideband HF, digital signal processing and improved link security offer a reliable, cost-effective alternative to satellite communications and allow users to rediscover the benefits that HF radio communication has to offer.

In the face of rising geopolitical tensions, HF communication is regaining strategic importance, offering a secure backbone in rapidly evolving operational landscapes.

Emerging Wideband HF Systems:

  • STANAG 5066 WBHF ARQ Systems – uses BULK COMSEC
  • STANAG 5066 Broadcast Systems – IP Based
  • STANAG 4691 MARLIN WBHF Systems
Ideal for naval shore stations, strategic ground sites, and large ship installations

STANAG 5066

STANAG 5066 "Technical Standards for HF Radio Link Layer and Application Support Protocols" is a NATO specification enabling various data applications to communicate via a common interface and share the HF radio circuit. The 5066 ARQ protocol stack makes provision for a number of applications to bind to it. The 5066 stack prioritises and interleaves data from the various applications in an appropriate manner whilst controlling the modem and transceiver to minimize data transfers and link turn-arounds. The key function of the STANAG 5066 ARQ is to ensure error-free data delivery over the HF link by ensuring that all data segments received in error are re-transmitted until all segments have been received correctly.

Interoperability

Interoperability among a diverse set of radio communication systems is crucial for the success of naval and strategic missions worldwide. Compliance with modem (MIL-STD-188-110D), ALE (MIL-STD-188-141D) and ARQ standards (STANAG 5066) ensure global interoperability by standardising HF communication product requirements.

Rapid Mobile is committed to advancing HF standardization, with our continued commitment to MIL-STD and STANAG as well as our efforts in contributing to the standardization of system configuration profiles, test systems and applications.

Achieving HF Interoperability

Standardisation: Adherence to globally recognised HF standards enable communication across different radio systems.

Specialized Testing: OEMs and military laboratories conduct rigorous testing to verify product and system compatibility.

Interoperability Exercises: Vendors collaborate in structured exercises to test, validate, and refine HF interoperability across diverse platforms..

HF House

The HF House concept was initially introduced in the STANAG 4538 specification (also included in MIL-STD-188-141D Appendix C) as a framework of standards for HF communication. It attempts to align the NATO standards with MIL-STDs to promote interoperability. The HF House focuses on the lower layers of the OSI network model and serves as a baseline for achieving HF communication interoperability. Standardisation, combined with interoperability exercises among vendors and specialised testing, is essential to ensure interoperability.

As HF standards continue to evolve, updates to the HF House are necessary. This includes the integration of wideband HF modem, wideband ALE and wideband ARQ standards, forming what is now referred to as the Wideband HF House.

The Wideband HF House shows the second (2G), third (3G), and fourth generation (4G) standards. The updated house also highlights the possible interactions between the Modem, ALE, ARQ and 2G, 3G, and 4G standards.

The extensions introduced by the Wideband HF House include the following:

  • MIL-STD-188-141D (4G ALE)
  • MIL-STD-188-110C and D (Wideband HF Modems, Contiguous)
  • STANAG 5066 (WB ARQ)

The software architecture of a 4G implementation caters for concurrent LSU decoding and for the management of 2G, 3G, and 4G linking, sessions, and traffic. This means that:

  • 4G ALE systems can set up links for legacy narrowband or wideband traffic.
  • 4G ALE systems are backwards compatible with 2G/3G ALE. To this end 4G ALE/WALE supports a scan rate compatible with 3G systems.
  • STANAG 5066 WB (Edition 4*) is the appropriate ARQ for MIL-STD-188-110C, D.

MIL-STD-188 (Military Standard)

MIL-STD-188 represents a series of military standards developed by the U.S. Department of Defence to ensure the compatibility, reliability, and interoperability of communication systems used by the military. These standards cover a wide range of technical requirements, performance benchmarks, and security protocols, to establish effortless HF communication across military platforms.

STANAG (Standardisation Agreement)

STANAG is a set of agreements established by NATO (North Atlantic Treaty Organization) that standardise military equipment, procedures, and communications across member nations, ensuring interoperability in joint operations. These standards cover various areas, from communication protocols to operational procedures, enabling NATO members to share information and resources during missions. Some STANAG standards overlap with MIL-STD specifications, providing additional interoperability between NATO and non-NATO forces. Our products are designed to comply with both, ensuring secure communication and interoperability in joint operations.

HF and VHF/UHF Equipment

Product Families

With decades of expertise in HF communications, RapidM understands the critical need for robust and interoperable solutions. We support system integrators and laboratories with a comprehensive range of maritime communication products, including advanced data modems, ALE controllers, and ARQ protocol units. Our products comply with the latest industry standards, including ISO, IEC, CE, MIL-STD-188-110B/C, MIL-STD-188-141B/C/D, and STANAG 4538, 4539, 4539/TDMA, 5066, and 4691. Built on a modular hardware platform, they ensure long-term sustainability with a 20-year service life and guaranteed spares availability. From rugged hardware to advanced PC software, RapidM provides secure, standards-compliant HF and V/UHF communication products for maritime and strategic operations.

RM Family

High-performance, standards-compliant, HF and VHF/UHF data modems for strategic, naval and commercial platforms

The RM product family is engineered for users who require high-performance, best-in-class data modems for satellite-independent BLOS communications that are fully compliant with MIL-STD and STANAG. Designed for strategic, maritime, narrowband, and wideband HF and VHF/UHF data communications, these products offer exceptional reliability.

The range includes HF and VHF/UHF data modems (conforming to MIL-STD-188-110A, MIL-STD-188-110B, MIL-STD-188-110C – wideband HF, STANAG 5069, 4285, 5065, 4529, 4415, 4539 and 4691), Automatic Link Establishment (ALE) functions for 2G ALE (conforming to MIL-STD-188-141A, MIL-STD-188-141B and MIL-STD-188-141C), Automatic Link Establishment (ALE) functions for 3G ALE (conforming to STANAG 4538 FLSU) and 3G Packet Data Modems (conforming to STANAG 4538 xDL) and Wideband Automatic Link Establishment (WALE) functions for 4G ALE (MIL-STD-188-141D).

The RM products share the same modular hardware platform and the units are internally powered by our TC family of modem modules. Our products provide excellent environmental specifications with respect to temperature, humidity, salt, fog, dust, shock, vibration and MTBF.

RM34 Ultra-Wideband SDM | 70 MHz – 500 kHz

The RM34 Ultra-Wideband Software Defined Modem (SDM) / 70 MHz is a purpose-built, standalone hardware platform for high-capacity data communication over V/UHF radio channels using STANAG 4691 waveforms. Designed to meet the requirements of naval and government end-users, the RM34 delivers high-performance, long-distance line-of-sight (LOS) data communications for strategic and maritime operations.


RM12 Wideband SDM & ALE – 48 kHz

The RM12 Wideband SDM & ALE is a high-performance wideband data modem for beyond-line-of-sight (BLOS) HF communications in channels from 3 to 48 kHz. Ideal for naval vessels, aircraft, and NATO shore stations, the RM12 supports MIL-STD-188-110D and STANAG 5069 waveforms, delivering data rates up to 240 kbps. It features 4G ALE (WALE) for fast and deep link establishment and supports 2G/3G ALE for seamless network integration. Built for longevity, the RM12 offers a 15-year lifecycle with 20 years of spares availability.


RM10 Wideband SDM & ALE – 24 kHz

The RM10 Wideband SDM & ALE is a high-performance data modem designed for beyond line-of-sight communications, supporting wideband HF channels with data rates up to 120 kbps. It offers advanced features like 4G ALE, WB-RDL waveforms for noisy environments, and compliance with MIL-STD-188-110C (App D) and STANAG 5069. Designed for naval, maritime, and government applications, the RM10 ensures reliable long-range communication in challenging conditions and is suitable for platforms like ships, submarines, and aircraft. It is also deployable in high-power NATO shore stations with configurations like BRASS, BRE1TA, and BRIPES.


RM8 Software Defined Modem & ALE – 3, 6 kHz

The RM8 Software Defined Modem & ALE Controller is a high-data-rate LF/HF modem and ALE controller, for standards-based strategic and maritime communications. Supporting long-distance point-to-point links and NATO BRASS and BRE1TA shore station deployments, the RM8 offers split-site 2G and 3G ALE with advanced scanning, channel selection, and XDL packet data. It fits into 19-inch racks and accommodates two units in a 1U slot.


RM6-A Data Modem & ALE – 3, 6 kHz

The RM6-A is a high data rate LF and HF data modem and ALE controller for standards-based BLOS naval and strategic data communications.


RM5 Rugged High-Speed Modem – 3 kHz

The RM5 is a MIL-STD-188-110A/B HF data modem with a rugged, field-hardened enclosure. The modem is created with disaster relief agencies in mind. These agencies often need standardised interoperability in harsh and unpredictable environments. The unit also fits well with military and paramilitary organisations.


RM Family Products ComparisonRM34 Ultra-Wideband SDM | 70 MHz – 500 kHzRM12 Wideband SDM & ALE – 48 kHzRM10 Wideband SDM & ALE – 24 kHzRM8 Software Defined Modem & ALE – 3, 6 kHzRM6-A Data Modem & ALE ControllerRM5 Rugged High-Speed Modem – 3 kHzRM2 HF & V/UHF Data Modem

Use

Naval and Strategic     
Government and Security   
Industrial/Commercial       

Installation

19-inch Rack-Mount     
Desktop  

HF Modems and Protocols (MIL-STD/STANAG)

Wideband HF Data Modem (MS110D, 3 - 48 kHz) 
Wideband HF Data Modem (MS110C, 3 - 24 kHz)  
HF Data Modem up to 19200 bps (2x3 kHz, 2-ISB)  [ ][ ]
HF Data Modem up to 9600 bps (3 kHz, SSB)      
4G ALE / WALE (141D, 3 - 48 kHz) 
4G ALE/WALE (141D, 3 - 24 kHz)[ ][ ]
3G ALE (S4538 FLSU)[ ][ ][ ]
3G Packet Data (S4538 xDL)[ ][ ][ ]
2G ALE[ ][ ][ ][ ][ ][ ]

V/UHF Modems and Protocols (MIL-STD/STANAG)

S4691-B MARLIN (20/25 kHz) [ ]
S4691-C MARLIN (100 kHz) 
S4691-D MARLIN (300 kHz) 
S4691-E MARLIN (500 kHz) 

Use with (see RC product family)

RC34 Ultra-Wideband Network Controller 
RC12 Wideband ARQ & IP Controller - 240 kbps    
RC10 ARQ Server and IP Controller    
RC8 S5066 ARQ Server and IP Gateway  

Interfaces

Local Control (Screen and Keypad)     
DTE Sync., Std. and High-speed Async. Modes     
DTE RS-422 (Balanced) and RS-423/RS-232 (Unbalanced)     
Data RS-232 (RX, TX, RTS, CTS, DCD)  
Data Std. and High-speed Async. Modes  
Data Ethernet     
Data/Control (Combined) Ethernet  
Remote Control Ethernet     
Remote Control RS-422     
Remote Control RS-485     
Remote Control RS-232       
Remote Control Protocol: RAP1/RIPC       
Remote Control Protocol: ASCII S5066, Annex E    
Radio Audio: 1 Radio   
Radio Audio: 2 Radios    
Radio Digital Audio: Vita 49.2  
Radio Control: 1 Radio, RS-232   
Radio Control: 2 Radios, RS-232    
Radio Ethernet   
Auxiliary Audio    
External GPS (RS-232) and PPS In       
GPS Antenna (MCX), Internal Receiver[ ][ ]  

Security

External Bulk Crypto Interface     

Power

AC Input     
DC Input[ ][ ]  
DC Power from Radio  

Availability Status

Available       
Replacement and Spares Only

[ ] = Option

RC Family

Standards-based Automatic Repeat Request (ARQ), IP data solutions and network controllers

The RC product family offers Automatic Repeat Request (ARQ) and IP data controller rack-mountable units for system integrators of red-side equipment. These products enable standards-based automatic repeat request (ARQ), IP data transfer, and network control. RC products are designed to be used in combination with our RM modems and external link encryptors. When paired with RM modems, they ensure error-free data (email, ACP messages and IP data) over HF and VHF/UHF links that can extend to thousands of kilometres. The units are designed to interface directly with standardized cryptographic equipment.

RC products have STANAG 5066 functionality embedded and represent a standardised RED-side equipment solution.

The RC products include the (mandatory) SIS (Subnet Interface Sublayer) Access Protocol that enables an application to connect to an HF Modem through a STANAG 5066 server over TCP/IP. In addition, several data application clients, e.g., IP, COSS, CFTP and HMTP are provided as embedded functions.

The RC10 and RC12 have added capabilities allowing it to operate in high-power NATO shore stations requiring STANAG 5066-based data services e.g., those with Broadcast and Ship-Shore (BRASS) including BRASS Initial Core Capability (BICC) and BRASS IP Enhanced System (BRIPES), BRASS Enhancements 1 Technical Architecture (BRE1TA) and BRASS Enhancements 2 Technical Architecture (BRE2TA) configurations.

RC34 Ultra-Wideband Network Controller | 1.92 Mbps

The RC34 Ultra-Wideband Network Controller is a software-defined OSI Layer 2 and Layer 3 product for V/UHF line-of-sight (LOS) radio data communication. Housed in a 19-inch rack-mountable unit, it features a STANAG 4691 Appendix A Mobile Ad-Hoc Relay Line of Sight Networking (MARLIN) controller.


RC12 Wideband ARQ & IP Controller – 240 kbps

The RC12 ARQ Server and IP Controller is a rack-mount platform designed for the STANAG 5066 ARQ protocol, enabling efficient data communication over HF and V/UHF radio links. It supports military messaging, email, chat, and IP applications, with an embedded MARLIN STANAG 4691 network controller for V/UHF ELOS links. The RC12 also features a STANAG 4591 MELPe voice coder for digital voice interoperability. Ideal for NATO and naval communication systems, it’s a robust solution for systems integrators.


RC10 Wideband ARQ & IP Controller – 120 kbps

The RC10 ARQ Server and IP Controller is a rack-mount platform for the STANAG 5066 ARQ protocol, enabling military messaging, email, chat, and IP applications over HF BLOS and V/UHF ELOS radio links. With an embedded STANAG 5066 protocol stack and MARLIN STANAG 4691 network controller, the RC10 is ideal for strategic and naval HF data communications, including NATO systems.


RC8 ARQ Server & IP Controller – 19.2 kbps

The RC8 ARQ Server & IP Controller is a purpose-built platform for Automatic Repeat reQuest (ARQ) communications functions based on STANAG 5066 and STANAG 4538. The RC8 complies to all the mandatory features and aspects of the STANAG 5066 Edition 3 specification.


RC8X4 Quad ARQ Server & IP Controller – 19.2 kbps

The RC8X4 Quad ARQ Server & IP Controller is a purpose-built stand-alone hardware platform housing four independent Automatic Repeat reQuest (ARQ) and Vocoder functions used in maritime and strategic long-range (BLOS) communications systems. The RC8X4 complies to all the mandatory features and aspects of the STANAG 5066 Edition 3 specification.


RC Family Products ComparisonRC34 Ultra-Wideband Network Controller | 1.92 MbpsRC12 Wideband ARQ Server & IP ControllerRC10 ARQ Server & IP ControllerRC8 ARQ Server & IP Controller

Use

Naval and Strategic    
Government and Security
Industrial/Commercial    

Installation

19-Inch Rack-Mount (Dedicated Hardware)    

ARQ & Network Protocols (STANAG)

S5066 Wideband ARQ Stack  
S5066 ARQ Stack   
S5066 CFTP Compressed Email Client  
S5066 HMTP Email Client  
S5066 Broadcast HMTP Email Client  
S5066 IP Client   
S5066 COSS Client (for ACP-127)   
SMTP, POP3  
IP to Sync. Converter   
Embedded IP Stack   
Embedded IP PEP[ ][ ]
Embedded S5438 Proxy
S4691-A MARLIN Controller (HF, 48 kHz, ≤ 240 kbps)[ ]
S4691-A MARLIN Controller (HF, 24 kHz, ≤ 120 kbps)[ ][ ]
S4691-A MARLIN Controller (UHF, 20/25 kHz, ≤ 96 kbps) [ ]
S4691-A MARLIN Controller (UHF, 100 kHz, ≤ 384 kbps) 
S4691-A MARLIN Controller (UHF, 300 kHz, ≤ 1152 kbps) 
S4691-A MARLIN Controller (UHF, 500 kHz, ≤ 1920 kbps) 
S4591 MELPe (2400 bps)[ ][ ]
S4591 MELPe (1200 bps)[ ][ ]

Supported Modem and Protocol Standards (connected modem)

Wideband HF Data Modems (MS110D, ≤ 240 kbps)  
Wideband HF Data Modems (MS110C, ≤ 120 kbps)  
2-ISB Data Modem (MS110B Appendix F)   
SSB Data Modems (MS110A/B, S4539)   
4G ALE / WALE (MS-141D)  
3G ALE (S4538 FLSU)   
3G Packet Modem (S4538 LDL, HDL & HDL+)   
2G ALE (MS-141A/B/C)   
S4691-B MARLIN (20/25 kHz, ≤ 96 kbps) [ ][ ]
S4691-C MARLIN (100 kHz, ≤ 384 kbps) 
S4691-D MARLIN (300 kHz, ≤ 1152 kbps) 
S4691-E MARLIN (500 kHz, ≤ 1920 kbps) 
Proprietary V/UHF Modems[ ]

Connected Software (Not RapidM)

ACP-127 Messaging Terminal   
User IP Application    
Chat/S4406 Messaging/Email Terminal    
Management System    

Use with Modem (see RM family)

RM34 
RM12 CompatibleCompatible
RM10Compatible Compatible
RM8CompatibleCompatible 
RM6-A/RM6 
RM5 

Interfaces to Modem

Control: On-Device Serial (RS-485, RS-422, RS-232)    
Control Ethernet   
Data: On-Device Sync. Serial DCE (RS-422, RS-423, RS-232)    
Data: Ethernet   
Auxiliary Audio  

Security

External Bulk Crypto Support    

Power

AC Input    

[ ] = Option

RI Family

RI10 IP-TO-SYNC Controller – 120 kbps

The RI10 IP-to-Sync Controllers are a pair of 19-inch rack-mountable hardware for transferring synchronous serial data over Ethernet (TCP/IP). By utilising the RI10, the transfer of encrypted bulk data over IP over extended distances for split-site systems are possible whilst leveraging on the already installed base of high-performance COMSEC devices. Besides, transferring the data, the RI10 product also operates as a split-site controller for configuration, control and status.


Product Lifespan

Our products are designed for a planned product availability of 15 or more years and spares availability of at least 20 years. In addition, we offer long-term, customer-specific configuration management.

We implement product life cycle management and obsolescence control to ensure that our products remain available for extended periods. If it becomes necessary to replace the hardware platform with a newer version in the future, RapidM will release -A or -B replacement products based on the new platform. The replacement product will then be recommended for new installations and projects. When a replacement product becomes available, a projected End-of-Availability (EOA) date for the existing product will be announced. The EOA date will give customers and systems integrators insights into the timeline on product availability for purchase. Ahead of the EOA date, a Last Buy Announcement (LBA) will be made to give customers a last opportunity to purchase the existing product. After reaching the EOA date, products bought will be repaired for the duration of the standard (2 years) and extended warranty periods (typically, up to 5 years) from the date of purchase. This means that products that were bought after the LBA, but ahead of the EOA date, will be maintainable by tapping into the available spares pool.

NATO and MIL-STD Specifications Mapped to RapidM RM and RC Products

DocumentDescriptionRM6-ARM8RM10RM12RM34RC8RC10RC12RC34

Modem Standards

MIL-STD-188-110A (click for more info)Interoperability and Performance Standards for Data Modems    
MIL-STD-188-110A, Appendix B39-Tone Parallel Mode    
MIL-STD-188-110B (click for more info)Interoperability and Performance Standards for Data Modems    
MIL-STD-188-110B, Appendix B39-Tone Parallel Mode    
MIL-STD-188-110B, Appendix CHF Data Modem Waveforms for Data Rates above 2400 bps    
MIL-STD-188-110B, Appendix EData Link Protocol    
MIL-STD-188-110B, Appendix FHF Data Modem Waveforms for Multiple Channel Systems    
MIL-STD-188-110C (click for more info)Interoperability and Performance Standards for Data Modems    
MIL-STD-188-110C, Appendix ALAN Interface[ ][ ]
MIL-STD-188-110C, Appendix B39-Tone Parallel Mode    
MIL-STD-188-110C, Appendix CHF Data Modem Waveforms for Data Rates above 2400 bps    
MIL-STD-188-110C, Appendix DHF Data Modem Waveforms for Single Contiguous Bandwidth up to 24 kHz  
MIL-STD-188-110C, Appendix FHF Data Modem Waveforms for Multiple Channel Systems    
MIL-STD-188-110DInteroperability and Performance Standards for Data Modems    
MIL-STD-188-110D, Appendix ALAN Interface  
MIL-STD-188-110D, Appendix B39-Tone Parallel Mode    
MIL-STD-188-110D, Appendix CHF Data Modem Waveforms for Data Rates above 2400 bps in 3 kHz Bandwidth    
MIL-STD-188-110D, Appendix DHF Data Modem Waveforms for Single Contiguous Bandwidth up to 48 kHz 
MIL-STD-188-110D, Appendix FHF Data Modem Waveforms for Multiple Channel Systems    
STANAG 5069 (Edition 1*)Technical Standards for Wideband Waveforms for Single Non-Hopping, Flexible-Bandwidth HF Channels 
STANAG 4539 (click for more info)Technical Standards for Non-Hopping HF Communications Waveforms    
STANAG 4539, Annex AFunctional Characteristics and Technical Overview of Non-Hopping HF Communications Waveforms    
STANAG 4539, Annex BTechnical Specifications to Ensure Interoperability of Serial Waveforms for Non-Hopping Multiple Application Operation on HF Channels    
STANAG 4539, Annex CPerformance Aspects of Waveforms for Non-Hopping Multiple Application Operation on HF Channels    
STANAG 4539, Annex DTechnical Specifications to Ensure Interoperability of Serial Waveforms for Non-Hopping TDMA Operation on HF Channels    
STANAG 4415 (click for more info)Characteristics of a Robust Non-Hopping, Serial Tone Modulators/Demodulator for Severely Degraded HF Radio Links    
STANAG 4415, Annex ARequired Characteristics of a Robust, Non-hopping, Serial Tone Modulator / Demodulator for Severely Degraded HF Radio Links    
STANAG 4415, Annex BExample Modulator - C language implementation of Transmit Waveform    
STANAG 4285 (click for more info)Characteristics of 1200/2400/3600 bits per Second Modulators/Demodulators for HF Radio Links    
STANAG 4285, Annex ARequired Characteristics of 1200/2400/3600 Bits per Second Single Tone Modulators/Demodulators for HF Radio Links    
STANAG 4285, Annex BEvaluation of Modems Employing the STANAG 4285 Waveform    
STANAG 4285, Annex CFirst Example of Demodulation Technique    
STANAG 4285, Annex DSecond Example of Demodulation Technique    
STANAG 4285, Annex EError Correction Coding, Interleaving and Message Protocols for use with the Standard Modulation Formats    
STANAG 4285, Annex FUse of the Synchronization Sequence for Signal Detection and Acquisition/Tracking of Doppler, Synchronization and Channel Parameters    
STANAG 4481 (click for more info)Minimum technical equipment standards for naval HF shore-to-ship broadcast systems    
STANAG 4529 (click for more info)Characteristics of Single Tone Modulators/Demodulators for Maritime HF Radio Links in 1240 Hz Bandwidth    
STANAG 5065Minimum Standards for Naval Low Frequency (LF) Shore-to-Ship Surface Broadcast Systems    
STANAG 5065, Annex ATerms and Definitions    
STANAG 5065, Annex BMinimum Standards for Naval LF Surface Broadcast Transmitting (Shore Station) and Receiving (Ship Station) Systems    
STANAG 5065, Annex CBaseband Processing and Modulation    
STANAG 5065, Annex DBaseband Description of MSK    
STANAG 4197Modulation and Coding Characteristics that must be common to assure Interoperability of 2400 bps Linear Predictive Encoded Digital Speech Transmitted over HF Facilities    

V/UHF Modem Standards

STANAG 4691 (Edition 1)Multi-Hop IP Networking with Legacy UHF Radios: Mobile Ad Hoc Relay Line-Of-Sight Networking (MARLIN)      
STANAG 4691, Annex AMobile Ad Hoc Relay Line-Of-Sight Networking (MARLIN) Profile   
STANAG 4691, Annex BTechnical Specifications to Ensure Interoperability of Serial Waveforms for 25 kHz Bandwidth Line-Of-Sight VHF and UHF Radio Data Communications  
STANAG 4691, Annex CTechnical Specifications to Ensure Interoperability of Serial Waveforms for 100 kHz Bandwidth Line of Sight VHF and UHF Radio Data Communications 
STANAG 4691, Annex DTechnical Specifications to Ensure Interoperability of Serial Waveforms for 300 kHz Bandwidth Line of Sight VHF and UHF Radio Data Communications 
STANAG 4691, Annex ETechnical Specifications to Ensure Interoperability of Serial Waveforms for 500 kHz Bandwidth Line of Sight VHF and UHF Radio Data Communications 

HF ALE Standards

MIL-STD-188-141BInteroperability and Performance Standards for Medium and High Frequency Radio Systems    
MIL-STD-188-141B, Appendix AAutomatic Link Establishment System    
MIL-STD-188-141B, Appendix BLinking Protection    
MIL-STD-188-141B, Appendix CThird-Generation HF Link Automation   
MIL-STD-188-141B, Appendix EApplication Protocols for HF Radio Networks   
MIL-STD-188-141CInteroperability and Performance Standards for Medium and High Frequency Radio Systems    
MIL-STD-188-141C, Appendix AAutomatic Link Establishment System (Second Generation [2G])    
MIL-STD-188-141C, Appendix BLinking Protection    
MIL-STD-188-141C, Appendix CThird-Generation HF Link Automation   
MIL-STD-188-141C, Appendix EApplication Protocols for HF Radio Networks   
MIL-STD-188-141DInteroperability and Performance Standards for Medium and High Frequency Radio Systems    
MIL-STD-188-141D, Appendix AAutomatic Link Establishment System (Second Generation [2G])    
MIL-STD-188-141D, Appendix BLinking Protection    
MIL-STD-188-141D, Appendix CThird-Generation HF Link Automation   
MIL-STD-188-141D, Appendix EApplication Protocols for HF Radio Networks   
MIL-STD-188-141D, Appendix GWideband Automatic Link Establishment System (WALE) (Fourth Generation (4G))  
MIL-STD-188-141D, Appendix HHalfloop Linking Protection Algorithm (Requires Export Permit *)  
STANAG 4538Technical Standards for an Automatic Radio Control System for HF Communications Links   
STANAG 4538, Appendix AFunctional Characteristics and Technical Overview of an Automatic Radio Control System for HF Communication Links   
STANAG 4538, Appendix BPerformance Characteristics of an Automatic Radio Control System for HF Communication Links   
STANAG 4538, Appendix CTechnical Specifications to Ensure Interoperability of an Automatic Radio Control System for HF Communications Links   

ARQ Standards

STANAG 5066 (click for more info) (Edition 2)Profile for High Frequency (HF) Radio Data Communications   
STANAG 5066, Appendix ASubnetwork Interface Sublayer   
STANAG 5066, Appendix BChannel Access Sublayer   
STANAG 5066, Appendix CData Transfer Sublayer   
STANAG 5066, Appendix DInterface between Data Transfer Sublayer and Communications Equipment   
STANAG 5066, Appendix EHF Modem Remote Control Interface   
STANAG 5066, Appendix FSubnetwork Client Definitions. See table below for more info   
STANAG 5066, Appendix GUse of Waveforms at Data Rates Above 2400 bps   
STANAG 5066, Appendix HImplementation Guide and Notes   
STANAG 5066, Appendix IMessages and Procedures for Frequency Change   
STANAG 5066 (click for more info) (Edition 3)Profile for High Frequency (HF) Radio Data Communications   
STANAG 5066, Appendix ASubnetwork Interface Sublayer   
STANAG 5066, Appendix BChannel Access Sublayer   
STANAG 5066, Appendix CData Transfer Sublayer   
STANAG 5066, Appendix DInterface between Data Transfer Sublayer and Communications Equipment   
STANAG 5066, Appendix EHF Modem Remote Control Interface   
STANAG 5066, Appendix FSubnetwork Client Definitions. See table below for more info   
STANAG 5066, Appendix GUse of Waveforms at Data Rates Above 2400 bps   
STANAG 5066, Appendix HImplementation Guide and Notes   
STANAG 5066, Appendix IMessages and Procedures for Frequency Change   
STANAG 5066, Appendix JGeneral Requirements for Enhanced Media-Access-Control (MAC) Capabilities in Multi-Node STANAG 5066 Networks  
STANAG 5066, Appendix KHigh-Frequency Carrier-Sense Multiple-Access (CSMA) Protocols   
STANAG 5066, Appendix LHigh-Frequency Wireless Token-Ring-Protocol (WTRP) Requirements  
STANAG 5066 (Edition 4)Profile for High Frequency (HF) Radio Data Communications   
STANAG 5066, Appendix ASubnetwork Interface Sublayer   
STANAG 5066, Appendix BChannel Access Sublayer   
STANAG 5066, Appendix CData Transfer Sublayer   
STANAG 5066, Appendix DInterface between Data Transfer Sublayer and Communications Equipment   
STANAG 5066, Appendix FSubnetwork Client Definitions   
STANAG 5066, Appendix JGeneral Requirements for Enhanced Media Access Control (MAC) Capabilities in Multi-Node STANAG 5066 Networks  
STANAG 5066, Appendix KHigh-Frequency Carrier-Sense Multiple-Access (CSMA) Protocols   
STANAG 5066, Appendix LHigh-Frequency Wireless Token-Ring-Protocol (WTRP) Requirements  
STANAG 5066, Appendix NGuidance on Address Management in STANAG 5066 Networks  
STANAG 5066, Appendix OHF Operator Chat  
STANAG 5066, Appendix PACP 127 & Character-Oriented Serial Stream  
STANAG 5066, Appendix RRouting Sublayer  
STANAG 5066, Appendix SSIS Access Protocol  
STANAG 5066, Appendix UIP Client (excluding IPv6 support)  
STANAG 5066, Appendix VCompressed File Transfer Protocol (CFTP)  

Electromagnetic Interference Requirements Standard

MIL-STD-461GMilitary Standard: Electromagnetic Interference Characteristics Requirements for Equipment         

Environmental Engineering Requirements Standard

MIL-STD-810GDepartment of Defence Test Method Standard Environmental Engineering Considerations and Laboratory Tests         

Quality Management

ISO 9001:2015Quality Management System: Requirements         
AQAP 2110NATO Quality Assurance Requirements for Design, Development and Production         

Military Standard Software Development and Documentation

MIL-STD-498Software Development and Documentation         

  = Fully compliant implementation* = Standard not yet released


Supporting table(s)

STANAG 5066 Annex F: expanded

Annex F.xDescriptionRC8RC10RC12RC34
Annex F.3COSS Client   
Annex F.5HMTP Client  
Annex F.12IP Client   
Annex F.14CFTP Client  

Test Systems and Profiles for Interoperability

HF Systems have complex configurations and are usually configured by subject matter experts. RapidM is committed advancing interoperability by providing standardized configuration profiles, test systems, applications and test procedures, as well conducting regular interoperability exercises and testing to maintain long-term compatibility in real-world operations.

We propose the standardisation of STANAG 5066 / ARQ, STANAG 4591 / MARLIN, and STANAG 4591 / MELPe test systems and configuration profiles, to ensure compatibility across all layers of the radio communication system—from the Application Layer (L7) to the Physical Layer (L1). To simplify deployment and enhance consistency, configuration profiles can be embedded in products as factory presets. RapidM has developed specialised test systems and configuration profiles that streamline this process, reducing complexity while ensuring reliable performance and interoperability across all platforms.

  • Standardised Configuration Profiles – for S5066, S4691 and S4591
  • Standardised Test Systems – for S5066 / ARQ, S4691 / MARLIN and S4591 / MELPe
  • Standardised Applications
  • Standardised Test Procedures
  • Continuous product and radio sub-systems testing to verify variable configuration parameters
  • Regular exercises between nations and vendors to test and refine HF interoperability

NATO BRASS: Overview and Enhancements

NATO BRASS (Broadcast and Ship to Shore) is HF radio system definition for long-range communication between naval vessels and shore stations. Continuous broadcasting from shore over wide coverage areas over multiple HF frequencies can deliver messages to multiple ships. Therefore, NATO BRASS enable ships in EMCON (Emission Control – Radio Silence) to still receive critical broadcast messages.

In addition to legacy BRASS broadcast, STANAG 5066 ARQ enable point to point communication in ship to shore, maritime rear link (MRL) and ship to ship.

There have been two technical enhancements to the original NATO BRASS system approach:

BRE1TA: BRASS Enhancement 1 Technical Architecture (BRASS / E1)

  • Higher HF throughput using S 4539 (SSB, 3 kHz) and MS 110B App. F (ISB, 2x3kHz) Autobaud Data Modems
  • Support for 3G ALE / S4538 FLSU with Automatic Link Maintenance (ALM)
  • S4406 is introduced as the NATO standardized successor to ACP-127
  • IP-over-HF services (e.g. C2 / FTP) over S5066, IP Client
  • S5066 Collision avoidance method 1 – CSMA (DCD Line & Back-off Slots)
  • S5066 Collision avoidance method 2 – WTRP (Token Ring)

BRE2TA: BRASS Enhancement 2 Technical Architecture (BRASS / E2)

  • Wideband HF data modems using STANAG 5069 / MS110D App. D (3 - 48 kHz).
  • Wideband ALE (WALE) – MS141D App. G (3 - 48 kHz)
  • UDP/IP over HF services over S5066 (IP Client)
  • MS141D App. H – Linking Protection
  • HF Network-based IP services over WBHF and S5066 (XMPP Chat)
  • XMPP – eXtensible Messaging and Presence Protocol

Below we provide sample profiles for interoperability in HF systems.

Test and Reference System: S5066 Profiles

We have various standardised configuration profiles aimed at reducing configuration complexity of HF systems. Below are examples of S5066 BRE1TA / Broadcast and BRE2TA / Ship-to-Ship concept configuration profiles.

BRE1TA Broadcast
This configuration profile architecture illustrates a BRASS/BRE1TA broadcast narrowband radio link, with a RC12 (S5066 NB), an RI12 Split-Site Controller, and a RM12 (S4539 (SSB, 3 kHz), MS110B App. F (ISB, 2 x 3kHz)) using 3G ALE. BRASS/BRE1TA broadcast links make use of S5066 and COSS, HMTP & IP clients. Data services include ACP-127 messaging, HF Email and S4406 Annex E, MMHS messaging.
BRE2TA S/S – Ship Circuit
This configuration profile architecture illustrates a BRASS/BRE2TA Ship-to-Ship (S-S) radio circuit, with a RC12 (S5066 WB) and a RM12 (S5069, MS110D App. D (ISB, 2 x 3kHz)) typically using 4G ALE / WALE. BRASS/BRE2TA S-S data services include HF Email, S4406 MMHS and (UDP/TCP) IP data for maritime situational awareness. Broadcast links make use of S5066 and COSS, HMTP & IP clients.
RapidM RT Family Product Range

Test and Reference System: S4691 Profiles

We have various standardised configuration profiles aimed at reducing configuration complexity of HF systems. Below is an example of a STANAG 4691 broadcast ship cicuit configuration profile.

S4691 – Ship Circuit
This configuration profile architecture illustrates a STANAG 4691 MARLIN fixed frequency ship circuit, with a RC12 (S4691) and a RM12 (MS110C/D). Data transfer is enabled in multi-node, multi-hop dynamic radio circuit networks with MANET built in. STANAG 4691 MARLIN was originally developed to provide connectivity amongst ships at sea and slow-moving aircraft via the use of LOS UHF radio links. HF modernisation programmes are calling for S4691 MARLIN over ELOS WBHF.
RapidM RT Family Product Range

Test and Reference System: S4591 Profiles

We have various standardised configuration profiles aimed at reducing configuration complexity of HF systems. Below is an example of a STANAG 4591 fixed frequency ship circuit.

S4591 – Ship Circuit
This configuration profile architecture illustrates a STANAG 4591 Enhanced Mixed Excitation Linear Prediction (MELPe) fixed frequency ship circuit, with a RC12 (S4591) and a RM12 (MS110D). MELPe is the NATO specification for SDV (Secure Digital Voice).
RapidM RT Family Product Range

For detailed information regarding our Test and Reference systems, get in touch with us.

STANAG 4691 TDMA Networked Communications in V/UHF band

The Allied Communications Publication AComP-4691, "Multi-Hop IP Networking with Legacy UHF Radios: Mobile Ad hoc Relay Line of Sight Networking (MARLIN)", also referred to as STANAG 4691, is a NATO specification enabling data transfer in a multi-node, multi-hop dynamic V/UHF radio circuit network. The MARLIN standard was originally developed to provide connectivity amongst ships at sea and slow-moving aircraft via the use of Line-of-Sight (LOS) V/UHF radio links. The RC10 and RC12 offer a VHF / UHF network controller function conforming to AComP-4691 / STANAG 4691 Annex A “MARLIN”. The MARLIN controller is based the use of a synchronous Time Division Media Access (TDMA) scheme called Distributed Slot Reservation Media Access (DSRMA). Each MARLIN node maintains a fixed allocation of time slots in each frame. The number of allocated slots per node are automatically adjusted based on data demands, using the dynamic bandwidth allocation mechanism. For the Rapid Mobile STANAG 4691 MARLIN HF solution, the RC12 is utilised in conjunction with the narrowband and wideband HF waveforms provided by the RM12. See our RC12 S4691 Datasheet for a conformance table.

Test Equipment & Tools

RapidM offers a range of hardware and software tools for testing and evaluation, including:

Bit Error Rate Testers (BERT)

RapidM Services
RapidM's Lab utilises our in house stand-alone Bit Error Rate Test Units
  • RB8, RB10, RB12 units and PC UI for testing data systems
  • Generates test data streams to evaluate HF systems
  • Detects bit errors and missed bits (bit slips)
  • Provides serial DTE interface with RS-422 or RS-232 electrical modes
  • Sync.: 50 bps to 240 kbps, Async.: 50 bps to 230.4 kbps
  • Supports standard PRBS 63, 511 or 2047 bit, custom text or User Defined PRBS

BERT function is also provided in the RC10 and RC12 Controllers as a mode of operation used for commissioning a deployed circuit.

Channel Simulators

RapidM Services RS24 Channel Simulator
RapidM's lab utilises our own in-house stand-alone HF and V/UHF channel simulators.
  • RS8, RS10, RS14 and RS24 standalone units for simulating HF channel conditions
  • RS14 standalone unit simulates wideband HF channel conditions for reproducible performance evaluation of modems and ALE waveforms
  • Supports analog and digital audio interfaces (Vita 49.2)
  • Used by RapidM for the performance evaluation of MS110D modem and MS141D ALE solutions
  • Understands ALE channel scan and call commands and switches channels accordingly
  • Offers various channel models, including HF Watterson-Coon, HF ITU, and HF CCIR
  • Supported bandwidths: 3 to 48 kHz
  • HF Arctic Channel Examples
  • Asymmetric SNR: Dual left & right channel for full ISB testing, Separate forward & reverse channels for ARQ testing
  • Presets for CCIR & ITU channels and MIL-STD 110D conditions.
  • Doppler Simulation: Sweep and offset
  • ALE scan interface (supports WALE, 3G & 2G scan rates)
  • Interference Tone Simulation for S4415 tone excision
  • Interference Signal Simulation for WALE occupancy / channel negotiation

Automated Test Controller (ATC) Software

  • Executes test procedures according to specified test scenarios
  • Provides test coverage for functional and performance verification, compliance to standards
  • Supports modem standards (NB, WBHF serial modems, FSK etc.)
  • Supports ALE standards (2G, 3G and 4G)
  • Supports ARQ standards (5066, 4691)
  • Offers interoperability with 3rd party radio equipment
  • Generates test logs and test reports

RapidM System Integration Test Lab (SITL)

RapidM’s System Integration Test Lab is equipped and set up to qualify reference circuits and perform conformance-to-standards testing of our products. Our test lab capability can qualify S5066, S4691 and other systems using BRASS, BRE1TA and BRE2TA system profiles.

Our RCM (Radio Circuit Management) software is integrated at the SITL for customer-specific requirements.

Abbreviations and Acronyms

AbbreviationMeaning
2G ALESecond Generation Automatic Link Establishment
3G ALEThird Generation Automatic Link Establishment
4G ALEFourth Generation Automatic Link Establishment
ACAlternating Current
ACPAllied Communications Protocol
ACSAutomatic Channel Selection
ALEAutomatic Link Establishment
ALMAutomatic Link Maintenance
ANDVTAdvanced Narrowband Digital Voice Terminal
ASYNCAsynchronous
ATCAutomated Test Controller
BERTBit Error Rate Tester
BLOSBeyond Line-of-Sight
BRASSBroadcast and Ship to Shore
BRE1TABRASS Enhancements 1 Technical Architecture
BRE2TABRASS Enhancements 2 Technical Architecture
BWBandwidth
C2Command and Control
CASChannel Access Sublayer
CCIRConsultative Committee on International Radio
COSSCharacter-Oriented Serial Stream
CSChannel Simulator
CSMACarrier Sense Multiple Access
CTRLControl
CTSClear To Send
DCDirect Current
DCDData Carrier Detect
DCEData Communications Equipment
DRCData Rate Change
DSRMADynamic Slot Reservation Multiple Access
DTEData Terminal Equipment
DVDigital Voice
ELOSExtended Line-Of-Sight
EMCElectromagnetic Compliance
ETHEthernet
FFFixed Frequency
FLSUFast Link Setup
GPSGlobal Positioning System
HALFLOOPTweakable block cipher that is used to protect auto-matic link establishment messages in high frequency radio.
HDLHigh-throughput Data Link protocol
HMTPHF Mail Transfer Protocol
IBInterleaver Block
IPInternet Protocol
ISBIndependent Sideband
ITUInternational Telecommunication Union
LANLocal Area Network
LBTListen-Before-Transmit
LBRListen-Before-Response
LDLLow-latency data link protocol
LFLow Frequency
LOSLine-Of-Sight
LPLinking Protection
LSBLower Sideband
LSULink Setup
LQALink Quality Analysis
MACMedia Access Control
MANETMobile AdHoc Network
MARLINMaritime Rear Link
MELPeMixed Excitation Linear Prediction Enhanced
MHSMessage Handling System
MIL-STDMilitary Standard
MMHSMilitary Message Handling System
NATONorth Atlantic Treaty Organisation
NBNarrowband
NTPNetwork Time Protocol
PAPower Amplifier
PEPPerformance-Enhancing Proxy
PTTPress-To-Talk
RAP1Radio Access Protocol 1
RCMRadio Circuit Management
RDLRapid Data Link
RFRadio Frequency
RNRoyal Navy
RTSRequest To Send
S-SShip-to-Ship
SDVSecure Digital Voice
SISSubnetwork Interface Sublayer
SODARKThe SoDark cipher is used to protect transmitted frames in the second and third generation automatic link establishment (ALE) standards
SDMSoftware Defined Modem
SITLSystem Integration Test Lab
SNRSignal-to-Noise Ratio
SSBSingle-Sideband
SYNCSynchronization
TCPTransmission Control Protocol
TDMATime Division Multiple Access
TFTrusted Filter
UDPUser Datagram Protocol
USBUpper Sideband
USNUnited States Navy
WALEWideband ALE
WBWideband
WBHFWideband HF
WTRPWireless Token Ring Protocol
xDLPacket Data Link Protocol (including LDL, HDL/HDL+ & RDL)
XMPPeXtensible Messaging and Presence Protocol
ZCryptographic Equipment / Crypto

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