ED-137 VoIP Air Traffic Management Software

Air Traffic Management (ATM) voice communication systems that utilize costly TDM circuits can be migrated to use Voice over Internet Protocol (VoIP) technology for lower cost and maintenance. The European Organization for Civil Aviation Equipment (EUROCAE) has defined ED-137 standards for air-ground and ground-ground communications.  This allows end users to select products adhering to these standards from different vendors instead of relying on single sourced custom solution, and still be confident of meeting operational and interoperability requirements.

VOCAL has implemented a software radio solution that complies with ED-137 1B standard. It is ideally suited for ATM radio manufacturers/system integrators looking for software to complement their hardware/software offerings. The software can be configured and deployed to run on the VCS(CWP) or GRS side as receiver, transmitter or transceiver, and only those features needed can be selected. This allows for small footprint installations and efficient use of processing resources, minimizing capital costs.

ED-137 Supported Features

• Best Signal Selection (BSS)
• Climax time delay (CLD)
• Remote Radio Control single frequency (RRC single)
• Remote Radio Control paired frequency (RRC paired)
• Request for Measurement (RMM)
• Request for Measurement Answer (RMM MAM)
• WG67 key-in package
• Permissions Lists
• Linked Sessions
• SELCAL tones
• Multicast of aircraft audio to multiple VCSs
• Summation of multiple VCS audio streams to radio
• Prioritization of VCS audio streams

Please refer to the Use Case Scenarios link below.

VOCAL’s software internal architecture provides for the ability to build multi-functional products through partitioning of IP bandwidth and separation of hardware interfaces. For instance, running ED-137 air-ground software connected to radios on some channels in conjunction with ground-ground communication connected to telephony equipment on other channels. Each external interface has its own distinct addressing, allowing for parallel execution and co-existence.

VOCAL software is capable of running on multiple operating systems including its own LANsEND and can be built to run on different computing platforms. It can be a configured as a standalone product or be incorporated into another application as a library.

The ED-137 module provides a flexible programming API for controlling, monitoring and configuring all communication aspects. An easy to use web interface is standard as is a command line interface for performing quick routine debugging and configuration tasks. The API provides easy access to manipulate the RTP headers and receive updates for SIP, SDP and RTP changes.

ED-137 RTP TX and RX headers
ED-137 RTP TX and RX headers

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The NATO Standardization Office has published AComP-5634 “IP Access to Half Duplex Radio Networks” or IOP-HD, also referenced as STANAG 5634, which uses ED-137b as a mechanism to allow IP networks of one nation to access half-duplex Radio Networks of another nation.

VOCAL’s ED-137 radio solution is optimized for performance on both standard X86/X64 architectures as well as DSP and RISC architectures from TI, ADI, ARM, AMD, Intel and other leading vendors. Custom designs are also available for our clients.  Contact us for a demo and to discuss your specific ED-137 radio application requirements.

Radio over IP Solutions


supported platforms

VOCAL’s software is available for a variety of platforms, including the following . Please contact us for specific RoIP supported platforms.

ProcessorsOperating Systems
  • Texas Instruments – C6xx (TMS320C62x, TMS320C64x, TMS320C645x, TMS320C66x, TMS320C67x), DaVinci, OMAP, C5xx (TMS320C54x, TMS320C55x)
  • Analog Devices – Blackfin, ADSP-21xx, TigerSHARC, SHARC
  • PowerPC, PowerQUICC
  • MIPS – MIPS32, MIPS64, MIPS4Kc
  • ARM – ARM7, ARM9, ARM9E, ARM10E, ARM11, StrongARM, ARM Cortex-A8/A9/A15/A3x/A5x/A7x, Cortex-M3/M4
  • Intel / AMD – x86, x64 (both 32 and 64 bit modes)
  • Linux, uClinux, BSD, Unix
  • Microsoft Windows ACM / RTC / CE / Mobile
  • Apple iOS / iPhone / iPad & MacOS
  • eCOS / eCOSPro
  • Google Android
  • Green Hills Integrity
  • Micrium μCOS
  • Symbian
  • Wind River VxWorks