interoperability. Basis for HF interoperability communications Interoperability is a critical issue for the disparate entities which use radiocommunications to fulfill the needs of organizations. Largely due to the ubiquity of 2G ALE, it became the primary method for providing interoperability on HF between governmental and non-governmental disaster relief and emergency communications entities, and amateur radio volunteers. With digital techniques increasingly employed in communications equipment, a universal digital calling standard was needed, and ALE filled the gap. Nearly every major HF radio manufacturer in the world builds ALE radios to the 2G standard to meet the high demand that new installations of HF radio systems conform to this standard protocol. Disparate entities that historically used incompatible radio methods were then able to call and converse with each other using the common 2G ALE platform. Some manufacturers and organizations have used the AMD feature of ALE to expand the performance and connectivity. In some cases, this has been successful, and in other cases, the use of proprietary preamble or embedded commands has led to interoperability problems. Tactical communication and resource management ALE serves as a convenient method of beyond line of sight communication. Originally developed to support military requirements, ALE is useful to many organizations who find themselves managing widely located units. United States Immigration and Customs Enforcement and United States Coast Guard are two members of the Customs Over the Horizon Enforcement Network (COTHEN), a MIL-STD 188-141A ALE network. All U.S. armed forces operate multiple similar networks. Similarly, shortwave utility listeners have documented frequency and callsign lists for many nations' military and guard units, as well as networks operated by oil exploration and production companies and public utilities in many countries. Emergency / disaster relief or extraordinary situation response communications ALE radio communication systems for both HF regional area networks and HF interoperability communications are in service among emergency and disaster relief agencies as well as military and guard forces. Extraordinary response agencies and organizations use ALE to respond to situations in the world where conventional communications may have been temporarily overloaded or damaged. In many cases, it is in place as alternative back-channel for organizations that may have to respond to situations or scenarios involving the loss of conventional communications. Earthquakes, storms, volcanic eruptions, and power or communication infrastructure failures are typical situations in which organizations may deem ALE necessary to operations. ALE networks are common among organizations engaged in