The aviation industry has adopted AMHS (Aeronautical Message Handling Systems) for provision of ground to ground communication. Isode provides a set of ICAO (International Civil Aviation Organization) SARPs (Standard and Recommended Practices) conformant server products (M-Switch X.400, X.400 Message Store, and M-Vault), to provide an AMHS infrastructure.

X.400 provides an extensive and powerful set of features, and as a consequence, generic approaches to integrate applications are complex. Isode's AMHS Gateway API specifies a simple abstraction of the X.400 functionality to meet the needs of an AMHS Gateway to AFTN or CIDIN following the specifications in the ICAO SARPs for provision of an MTCU (Message Transfer and Conversion Unit).

The AMHS Gateway API is co-resident with M-Switch X.400, as the MTCU needs to access X.400 functionality that is not available over X.400 P3 or P7. The library provides all of the AMHS side of an AMHS/AFTN gateway, making it very straightforward for a vendor with an AFTN or CIDIN product to offer an AMHS gateway.

Deployment Targets

The Isode AMHS Integration library is designed for use by vendors building solutions for the aviation industry, in developing ground to ground applications that operate over AMHS, and for integrating AMHS applications with the AFTN and CIDIN networks.

Key Benefits

The Isode AMHS Integration Library offers the following benefits:

  • For developers of AMHS applications, it provides a very simple abstraction, which can be used with new applications or to support existing AFTN applications working directly over AFTN.
  • For AFTN vendors, it provides a simple mechanism to provide an AFTN/AMHS gateway or CIDIN/AMHS gateway, by abstracting key X.400 and gateway functionality.
  • Although the X.400 complexity is abstracted, the API is designed so that all X.400 services can be selected and modified if required.
  • The API is cross platform - available on both Windows, Linux, and Solaris
  • The API shares some common functionality with the Isode X.400 Client API product family.


The AMHS Gateway API is co-resident with M-Switch X.400. This is primarily intended for building AFTN or CIDIN gateways, which require access to X.400 (message transfer) service elements which are not available over P3 or P7. This architecture could be used for general AMHS applications, although Isode recommends use of the P3 architecture for AMHS applications co-located with M-Switch X.400.

Gateway Architecture



Manual of Technical Provisions for the Aeronautical Telecommunications Network (ATN). ICAO SARPS Doc 9705/AN965:The ATN SARPS, Sub volume 3, Ground to Ground Applications, Third edition. This document will be superseded by ICAO Doc 9880.

API Definition

  • The Isode manual, describing all of the Isode messaging APIs is here. Further practical information for developers using this API is given in the Isode AMHS Implementer's Guide.
  • The 'C' language Isode AMHS Gateway API definitions are available here and example progams are available here.
  • The Java language Isode AMHS Gateway API definitions are available here and example programs are available here.
  • Examples of the Tcl language Isode AMHS Gateway API are in the product release and are described here.