Methods and apparatus implementing systems and techniques for traversing a hierarchical layout template to accelerate a constraint-driven backtracking search for a solution of the layout template. The system has a large range of vertical adjustability. To originate a call, the telephony interface system connects the telephony device to the PSTN if the dialed digits for the call correspond to a predetermined telephone number or numbers, such as 911. If received, the identification token is identified as a token included in a list of valid tokens associated with the digital identity at an authentication system. The user workstation identifies in a hyperlink table a server and within this server the information andor the service associated with the position of the selected marked item.