1. The assembly of functional units that establishes data circuits between data terminal equipment (DTE) at data stations that are at different locations. 2. A network that transfers data among a group of interconnected stations. 3.Synonym telecommunications network. See Defense Data Network,  public data network,  synchronous data network. See also data circuit,  data station,  data terminal equipment,  functional unit,  integrated services digital network,  interconnection,  network,  transfer.