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The World-wide DSN Numbering Plan uses area codes (KYXs) to define the major geographical areas for the DOD’s regular DSN voice communications: Continental United States (CONUS) and Puerto Rico are covered by 312, 313, 322, 323, 392; Europe, 314, 324; Pacific, 315, 325; Alaska, 317, 327; Central Command (Southwest Asia), 318, 328; and Canada, 319, 329. Fifty-three codes are reserved for interfacing to the tactical network. Area codes 50X and 51X are assigned to the major geographic areas for dial-up data transfer. Area code 50X is ISDN capable and is used for high speed digital data/fax.

Each geographical area includes nodal switches that provide long-haul service for Private Branch Exchange (PBX), End Office (EO) and Remote Switching Units (RSU) subscribers. Some of these nodal switches have intertheater connectivity and serve as gateways for access to other theaters. The World-wide Numbering Plan addresses KYX codes assigned by geographical area and NNX codes assigned to Multi-Function Switches and Wide Area Network Soft Switches (WAN SS).


DISA has overall management responsibility for the DSN and is responsible for all KYX and NNX number assignments within the DSN and also specifies the interface criteria for networks connected to the DSN per 6211.02D, Defense Information Systems Network (DISN) Responsibilities, Jan. 24, 2012.