ACP 145 was specified to enable communication between CCEB Nations (Australia, Canada, New Zealand, UK, US) by defining a common interface standard for military messaging between nations.
Although you could build a full system by following ACP 145, it is primarily designed as a gateway specification, to enable communication between nations without specifying the details of how each nation operates and constraining the approach each nation takes with national networks.
In a new white paper on the Isode site, ACP 145: Isode Support for International MMHS Gateways, we give an overview of ACP 145, how it is supported by the Isode product set and how this can be used to support both STANAG 4406 national systems, and SMTP national systems using MIXER conversion.