Teleconferencing Terminal Management Server Access Control

The patent introduces a file management server as an intermediary component that centralizes access control management. This server mediates between users and shared documents, handling authentication and authorization requests. By placing the control logic in a dedicated intermediary server rather than distributing it across all terminals, the system achieves robust access control while managing complexity centrally, thus resolving the contradiction between security and system complexity.

The patent implements differential synchronous display where different terminals receive different sets of shared documents based on their user's access rights and roles. Instead of broadcasting all documents to all terminals uniformly, the system tailors the content distribution to each terminal's specific needs and permissions. This localized approach maintains collaboration efficiency for authorized users while reducing unnecessary network traffic to terminals that don't need certain documents.

The patent implements preliminary authentication and authorization where user permissions are verified before establishing communication paths for document sharing. The file management server pre-determines which users can access which documents and sets up the appropriate communication channels in advance. This preliminary action approach ensures security requirements are met while avoiding the need for complex real-time permission checking during active communication, thus reducing real-time processing complexity.