Envoy Data Link is a standalone, lightweight, high-speed digital data link that includes three integrated avionics modules – CMU, VDR and MCDU – that brings enhancements to safety and efficiency for flying in the Communications, Navigation, and Surveillance (CNS)/Air Traffic Management (ATM) environment. Envoy contains true Dual Stack functionality that allows a flight crew to change between FANS CPDLC and ATN B1 CPDLC based on airspace requirements.

Envoy Technical Description document TD-15000 Issue 2, uploaded June 30, 2021


• Low capital acquisition costs
• Reduced installation and maintenance costs
• Little or no impact on flight deck layout, avionics bay space and aircraft weight
• Lower certification costs
• Minimal spare provisioning and support expenses
• Shorter aircraft downtime for retrofit and upgrades
• Compliance with all CPDLC mandates in a single unit
• Scalable software applications to support future growth and evolving requirements
• Physical expansion bay available to support future growth and new capabilities



CPDLC-DCL (Controller Pilot Data Link Communications – Departure Clearance)

• Safety – Removes voice communications errors by receiving amended route clearances as text-formatted messages.
• Efficiency – Amended clearances are sent electronically to DCL-equipped aircraft while voice-only aircraft must wait to receive new clearances then read back and acknowledge. Once verified, just enter the new route clearance into the FMS.

Weather or traffic volume forces all departing aircraft to receive a new clearance

• DCL-equipped aircraft receive route clearance as a digital message that can be uploaded onto the FMS automatically or input manually.
• Average savings of DCL versus voice in adverse weather conditions or high traffic periods is about 5 to 10 minutes on average.



Envoy Cost Savings Calculator

Link to Calculator

  • Fuel – Fuel savings at engine idle (Running when needed)
  • Crew – Crew time savings (Pay to work, not wait)
  • Environment – Reduces carbon emissions
  • Power by the Hour – Engine wear, insurance and maintenance



Software Application– Certified to RTCA DO-178C Level C

FANS 1/A+ (CPDLC and ADS-C), ATN B1 CPDLC, AOC ACARS, Global Flight Tracking (GADSS), Secure Wireless Broadcast

Included Hardware– Environmental: RTCA DO-160G

CMU: ARINC 724B and 758, VDR: VDL Mode 0/A and VDL Mode 2, ARINC 750 and TSO-C160, MCDU: ARINC 739 and TSO-C113



FANS 1/A+ (CPDLC and ADS-C): Worldwide OperationsCertified for FANS 1/A+, VHF Mode A/2 and SATCOM

Envoy contains all hardware and software for FANS 1/A+ CPDLC and ADS-C for certified compliance with mandates across the North Atlantic Track System, European Tango routes, and other FANS routes throughout world.

NATS Mandate, Phase 2B, (FL350 – FL390) 12-2017, Phase 2C, (FL290+) 1-2020, and FAA NextGEN, NAS Tower, En Route Domains

ATN B1 CPDLC: European Operations – Fully certified for ATN B1 CPDLC, VHF Mode 2

Delivers ATN B1 CPDLC to operators requiring certified compliance with the European mandate. Beginning 2-2020, the ATN B1 CPDLC mandate requires ALL non-exempt aircraft operating above FL285 to have ATN B1 CPDLC equipment in designated airspace. EU Mandate: DLS-IR (EC) 29/2009 and 2015/310

True Dual Stack CPDLC: Worldwide OperationsFANS 1/A+ CPDLC and ATN B1 CPDLC in a single unit

The NATS, Tango routes, and European airspace represent a challenge to operators who require compliance with dual mandates. true Dual Stack software allows a flight crew to change between FANS CPDLC and ATN B1 CPDLC based on airspace requirements.

Other CMUs with expensive FMS changes allow only for FANS CPDLC or ATN CPDLC – not both – penalizing the operator for flight segments that are not in compliance. With Envoy, you maintain compliance with all ATC mandates no matter where you fly.



FAA NextGEN Services: United States OperationsTower and En Route Services (DCL and CPDLC)

Envoy supports the FAA NextGEN program and infrastructure, allowing operators in the U.S. National Airspace System to reduce delays and obtain more efficient routes, improve safety, and reduce congestion or adverse weather delays.

CPDLC Departure Clearance (DCL) Services

DCL is currently operational at 62 U.S. airports where controllers send text-based clearance instructions to flight crews instead of speaking over the radio. Air carrier dispatchers simultaneously receive the same information, giving all decision makers faster reactions to changes. Flight crews review the instructions and signal acceptance by pushing a button, and the instructions are then loaded into the aircraft’s flight management system.

En route CPDLC Services

FANS 1/A+ is built in so operators are prepared for En route CPDLC which began in 2019 with availability at all 20 centers by 2021.

AOC ACARS: Worldwide Operations – Full featured and customizable AOC ACARS unit

This full featured AOC ACARS unit is capable of standard ACARS messaging (OOOI, Weather, Position, and Engine reporting) per ARINC 618, 620, 622, and 623. Customizable menu layout, appearance, and color scheme, Customizable automation via events and trigger, Field loadable databases do not affect certification.

Air Traffic Services (ATS) Messaging

ATS messaging includes pre-departure, pushback, taxi, and oceanic clearances as well as D-ATIS and TWIP services.

Global Flight Tracking: Worldwide OperationsPosition Reports per ICAO 15-minute recommendation

Global Flight Tracking is enabled by sending position reports over the ACARS network, via terrestrial VHF or SATCOM.

Envoy Features Condition-based Reporting

By monitoring events and triggers, automated position reporting can change in frequency based on the monitored parameters.



Envoy Form  Factors

Envoy is highly configurable and available in two form factors that enable a wide range of retrofit installation configurations.

Envoy All-In-One

This is a pedestal mounted LRU that includes the hardware of three individual avionics units (CMU + VDR + CDU). Envoy’s functions can be displayed and controlled from the Envoy CDU or from an external MCDU with the built in A739 interface. For enablement of the Secure Wireless Broadcast, the Envoy All-In-One or Envoy Standalone CDU form factors are required.


Envoy Remote CMU + VDR

The Remote CMU + VDR is a 2MCU LRU intended for rack mounting in the electronics bay. The Remote CMU + VDR includes the hardware of two avionics units (CMU + VDR) and can mounted remotely. With the Remote CMU + VDR, all Envoy’s functions can be displayed and controlled from an external MCDU with the built in A739 interface.

Envoy Standalone CDU

For operators with shallow pedestals or with alternative mounting locations for data link display & control, Envoy is available in a Standalone CDU package that interfaces directly with the Envoy Remote CMU + VDR. The combination of the Envoy Standalone CDU and Remote CMU + VDR provides the same features and functions as the Envoy All-In-One unit with additional design and installation flexibility.




Secure Wireless BroadcastWireless Transmission of Aircraft Data and Messages

Envoy allows secure wireless broadcast of stored aircraft system data and messages. Messages are transmitted at specific intervals and received by an application running on a mobile device such as a tablet or smart phone.

Non-real time ACARS via secure wireless broadcast, Rapid deployment of low-cost mobile devices & apps, App-based data processing of ACARS data

ARINC 619 Interface (ACMS, MOQA and FOQA)Allows Sending DFDAU and CFDIU Reports

Configurable to work with many on aircraft and end system devices to provide data link capability for messages to or from existing systems. Devices include Flight Management Computers for requests such as Winds Aloft or Flight Plan updates. These are sent through the unit to the ground when initiated from the FMC. The response message from the ground is routed back to the FMC where the message and data are available.

ARINC 739 Interface (MCDU Control)Envoy can display/control other avionics functions

The integrated MCDU is capable of hosting other ARINC 739 avionics to display and control functions from the Envoy front panel.

Envoy functions can be displayed/controlled by other avionics
Envoy can also be hosted from other ARINC 739 MCDUs associated with an FMC. Existing MCDUs on the aircraft can display and control functions from the All-In-One unit or from the Remote CMU + VDR form factor.

ARINC 741 Interface (SATCOM)Iridium or Inmarsat for AOC ACARS and FANS 1/A+

From Envoy, connections are made to a 741 protocol compliant SDU data channel to support both FANS 1/A+ (CPDLC and ADS-C) messages and AOC ACARS message exchanges.

ARINC 615A (Data Loader)Updates via existing data loader or maintenance port

Supports ARINC 615A Ethernet data loaders for updates and uploading of user databases in the field without removing equipment from the aircraft using an aircraft data loader or the Envoy maintenance port via laptop application.



System InterfacesInterface with aircraft, operations, and network systems

ARINC 429 Interfaces to aircraft systems, ARINC 619 interface (CVR, ACMS, FOQA), ARINC 739 (MCDU), ARINC 740 and 744 (Printer), ARINC 741 (SATCOM: Iridium, Inmarsat), ARINC 615 (Data loader), Network: ARINC and SITA

System I/OFlexibility for current needs and future growth

ARINC 429: 18-inputs / 8-outputs, Discrete: 16-inputs / 8-outputs, Full Duplex RS-485: 2, CANbus: 1, 100BaseTx Ethernet Port (maintenance): 1, Secure Wireless Broadcast: 1

Envoy Interface Diagram


General SpecificationsApplicable to all Envoy form factors

Environmental Categories: RTCA DO-160G, Software Certification: RTCA DO-178C Level B, TSO-C113a Airborne Multipurpose Electronic Displays, TSO-C160a VDL Mode 2 Communications Equipment

Specifications: Envoy All-In-OneFully Contained Pedestal mounted LRU

Dimensions: 5.75” wide x 4.5” high x 8.5” deep, Mounting: DZUS Rail, Weight: 6.0 lbs. (2.7 kg), Power: 28 VDC, 25 Watts Typical, Operating Temperature -40 to +55C

Specifications: Envoy Remote CMU + VDRElectronics Bay Mounted 2MCU LRU

Dimensions: 2MCU, Operating Temperature: -55 to +70C, Power: 28 VDC, 25 Watts Typical.



Contact the Spectralux Data Link Team

Americas, Asia, and Oceania
Kim Collins
Phone: 425 285 3044
Email Kim

Europe, Middle East, and Africa
Ian Gilbert
Phone: +44 (0) 7515 026970
Email Ian


Download TD-15000 Brochure (Rev 4-26-20)

Download Envoy Brochure