Link 22 is a secure digital radio link in the HF and UHF bands, primarily used by military forces as a tactical data link.During the late 1980s, NATO, agreeing on the need to improve the performance of Link 11, produced a mission need statement that became the basis for the establishment of the NATO Improved Link Eleven (NILE) Program. This program specified a new tactical message standard in the NATO STANdardization AGreement (STANAG) 5522 to enhance data exchange and provide a new layered communications architecture. This new data link was designated Link 22 by NATO.The NILE program is funded and collaboratively conducted by seven nations under the aegis of a Memorandum Of Understanding (MOU).A steering committee controls the complete NILE program. The program is managed by the Project Management Office (PMO), located at the Space and Naval Warfare Command (SPAWAR)'s Program Management Warfare (PMW) 150 in San Diego, California. The PMO consists of a representative from each participating nation and a Project Manager from the US.The Link 22 goals are to replace Link 11, thereby removing the inherent limitations of Link 11; to improve Allied interoperability; to complement Link 16; and to enhance the commanders' war fighting capability.From 2007 to 2009 NILE nation Germany contracted German industry to enhance performance and tactical capabilities for Link 22 HF fixed frequency (FF) operation. Three goals were achieved: increased robustness for the standardized data rates (defined by MSN 1-6) gapless communication range extended up to 1000 NM increased throughput by additional high-speed waveformsIn 2012 Germany submitted the new HF-FF technology to NATO and NILE program, for ratification and adoption respectively.The Link 22 system is centered around its core component, the System Network Controller (SNC). This software exists as a single implementation, produced by the NILE PMO and owned by the NILE nations. To ensure compatibility across Link 22 implementations, all participants must use this SNC software. Each implementing nation will acquire this software and will implement it in a hardware environment suitable for its own application. Therefor the SNC is not available as commercial product and is applied by NILE PMO to NILE agreed Third-Party Sales nations at annual maintenance fee.An excellent overview and introduction to Link 22 provides the ""Link 22 Guidebook"" published by the NILE PMO in July 2009. This Guidebook has been written in a manner that provides suitable information for Link 22 operators, planners, managers, executives, developers, and testers. Given below is an abstract of chapter 1 of the Link 22 Guidebook. The other chapters 2-3 of the Link 22 Guidebook are only available to NILE and Third-Party Sales nations.