and local computer terminals for system users. Connections were provided for remote terminals using microwave, cable, satellite, or landline connections. The PWIN network was based on technology supplied by BBN Technologies, and experience gained from the ARPANET. Honeywell H716 computers, used as Interface Message Processors (IMPs) provided packet switching to network the PWIN sites together. The TELNET protocol was made available to the WWMCCS community for the first time to access remote sites. The first comprehensive test plan for PWIN was approved on 29 October 1973. On 4 September 1974, the Joint Chiefs recommended that the prototype network be expanded from three sites to six. The recommendation was approved on 4 December 1974. The new sites included the Alternate National Military Command Center; the Military Airlift Command at Scott AFB; and the US Readiness Command headquarters at MacDill AFB. Testing was conducted in 1976, called Experiment 1 and Experiment 2. Experiment 1, held in September took a crisis scenario borrowed from a previous exercise. Experiment 1 provided a controlled environment to test PWIN. Experiment 2 was held in October, during an exercise called Elegant Eagle 76. Experiment 2 was less controlled, so as to provide information about PWIN being able to handle user demands during a crisis. The results of the experiments were mixed. Another test called Prime Target 77 was conducted during the spring of 1977. It added two new sites and had even more problems than Experiment 1 and Experiment 2. Ultimately, operational requirements trumped the problems and development of an operational network was recommended during 1977. The Joint Chiefs of Staff approved PWIN’s operational requirements on 18 July 1977. PWIN expanded to include a number of other WWMCCS sites and become an operational WWMCCS Intercomputer Network (WIN). Six initial WIN sites in 1977 increased to 20 sites by 1981. References Pearson, David E., The World Wide Military Command and Control System, Maxwell Air Force Base, Alabama: Air University Press., 2000. External links WWMCCS Worldwide Military Command and Control System (globalsecurity.org) C2 Policy Evolution at the U.S. Department of Defense, David Dick and John D. Comerford The Worldwide Military Command and Control System: Evolution and Effectiveness, David E. Pearson Annotated bibliography on nuclear command and control from the Alsos Digital Library for Nuclear Issues Command and control in the United States Department of Defense Military communications of the United States Military globalization United States nuclear command and control