| 摘要 |
Digital exchange terminals are linked by earth satellite and terrestrial point-to-point time division trunks in a privately coordinatable time division switching and communication network serving to connectively link multiple ports attachable to separate voice telephone and data communication "subscriber" trunk lines. The terminals operate relative to the satellite in a time division multiple access (TDMA) system with a portion of the system capacity (traffic burst channels) variably allocated to the terminals by demand assignment. The demand assignment is autonomously controlled by the terminals through supervisory communications carried over dedicated satellite channels (Order Wires) also utilized for synchronization. Internally the terminals employ modular multiplex switching between ports and "virtual" channels (buffer stores) and voice activity compression (mapping of groups of up to n virtual channels into groups of up to m, m less than n, actual time division channels on the time division trunks). The activity compression serves to make the terrestrial and satellite channel resources of the system virtually available to more lines than can actually be served in one TDMA frame. External management (data processing) apparatus attached to a terminal line port supplies information stored by the terminals and used by the terminals to restrict options in selecting connection path segments between respective ports and virtual channels. Thus, the network system may be adapted on various levels to balance its traffic loads (demand assignment "short term", network management/reconfiguration "longer term", and physical relocation of terminal modules/ports "longest term"). |
