Abstract: An Operations Support System, comprised of a computer and workstation, stores digit analysis specifications for telecommunications call processing. A graphical user interface displays digit analysis specifications visually as subtrees made up of nodes representing the digits of the dialed number. Two subtrees can be displayed contemporaneously for evaluation and manipulation independently and from one to another. Operations performed on the nodes also operate on the embedded digit analysis specifications permitting manipulation of the specifications without the need to view or deal with the specifications themselves directly. Related information such as Routing Table Indexes and local exchange numbers called NXX numbers are displayed contemporaneous with display of a subtree of interest and are manipulated with regard to that subtree.