Connecting to the Defense Data Network using the DCA´s Network Access Component

On February 12, 1985 Aydin Monitor Systems, a division of Aydin Corporation, was awarded a competitively bid contract from the Defense Communications Agency (DCA) to design and develop a Network Access Component (NAC). The NAC is designed to facilitate subscriber access to the Defense Data Network (DDN). The DDN is a packet switching network that offers two significant advantages to its subscribers and to the Government. 1) It significantly reduces the cost of data communications by sharing communication lines, communication equipment, and network control facilities. 2) It permits incompatible subscriber terminals and hosts to communicate over the network, supporting the DoD goal for "interoperability". The NAC implements the DoD protocols in each of its three variations: Mini-TAC, TEP, and HFEP. The Mini-TAC is a Terminal Access Component that interfaces asynchronous terminals and synchronous terminals to the DDN. The TEP is a Terminal Emulation Processor that connects hosts to the DDN by emulating local terminals at the host. The HFEP is a Host Front End Processor that connects hosts to the DDN using a 300 Kbps host data link.