Switching and activity compression between telephone lines and digital communication channels
First Claim
1. In a network of multiplex switching stations linked via cyclically recurrent channels of communication facilities, each said station having multiple ports attachable to separate telephone and data line circuits external to said network and providing varied time division connection links between said line circuits and said facilities, representing segments of virtual connections relative to ports of other stations, station apparatus comprising:
- means for coupling communicatively with an ordered group of said recurrent channels;
random access storage means containing a group of storage locations accessible in ordered association with said group of channels;
means coupled to said storage means and channel coupling means for operating in each said recurrence cycle to assign selected said storage locations to successive said channels for ordered communicative coupling with said channels;
multiplex switch means operating cyclically in coordination with said recurrence cycles and in cooperation with apparatus at other said stations for providing variable call connection links between said ports and storage locations;
means for monitoring activity context of voice and data signals being handled between said line circuits and said switch means; and
means supplying indications of said monitored activity to said channel assignment means in ordered association with locations receiving respective traffic for controlling selection of said locations by said channel assignment means.
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Accused Products
Abstract
Digital exchange stations linked by earth satellite operate in a coordinately controllable time division switching and communication network system relative to externally attached telephone and data trunks. Modular switching equipment operating in coordination with satellite frames establishes and releases connection paths to trunk stores which interface with time and space domain channels of the system. Circuits through the system utilizing these paths are termed virtual connections because in different frames a circuit may be completed through different channels or even blocked under certain conditions. Telephone speech is converted between analog and digital forms relative to modular groups of 96 ports. Digital switching (slot interchange) equipment serving up to four groups (and cycling in coordination with satellite time division frames) cyclically completes local (intra-station) connections between ports and segments of toll (inter-station) connections between ports and locations in the trunk stores. The trunk stores comprise separate sections for system traffic bound to and from ports of the respective station. A duplicate arrangement of subsections in each section is alternately filled and emptied in successive frames; enabling the station to maintain continuity of communication relative to the system in successive frames. The 192 bit spaces of each location are filled in one frame and emptied in the next frame. Groups of 96 outbound locations are "virtually" associated for transmission with groups of 48 time division transmission channels of said facilities. The association operates by a process of selection termed voice activity compression (abbreviated VAC) based upon activity information developed at the port interface and carried through the switching equipment in positional association with trunk locations. The VAC process assigns only locations (virtual channels) containing activity to up to 46 of the 48 time channels, eliminating any excess of active virtual channels (over 46) in a selective order of priority. VAC mask information transmitted in a separate one of the 48 time channels indicates the virtual-to-real (96-to-46) assignment for the respective group in the respective frame. A bit in the mask for each virtual channel of the group indicates the assignment or elimination of the respective virtual channel. Assigned channels are transmitted in the time order of respective mask bits. Establishment of virtual connections is restricted system-wide by tables stored in the stations. These tables are subject to external modification and may contain path exclusion information enabling the system to remain effectively operational with inoperative elements.
118 Citations
13 Claims
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1. In a network of multiplex switching stations linked via cyclically recurrent channels of communication facilities, each said station having multiple ports attachable to separate telephone and data line circuits external to said network and providing varied time division connection links between said line circuits and said facilities, representing segments of virtual connections relative to ports of other stations, station apparatus comprising:
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means for coupling communicatively with an ordered group of said recurrent channels; random access storage means containing a group of storage locations accessible in ordered association with said group of channels; means coupled to said storage means and channel coupling means for operating in each said recurrence cycle to assign selected said storage locations to successive said channels for ordered communicative coupling with said channels; multiplex switch means operating cyclically in coordination with said recurrence cycles and in cooperation with apparatus at other said stations for providing variable call connection links between said ports and storage locations; means for monitoring activity context of voice and data signals being handled between said line circuits and said switch means; and means supplying indications of said monitored activity to said channel assignment means in ordered association with locations receiving respective traffic for controlling selection of said locations by said channel assignment means. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method of using m recurrent channels of a multiplex communication facility to convey information from n (greater than m) input source telephone and data trunk line circuits associated transmissively with one access node of said facility to n respective destination lines associated receivably with other access nodes of said facility comprising:
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recurrently transferring information from said input line circuits into n randomly accessible stores switchably paired with said source lines; varying the pairings of said line circuits and stores relative to the accessibility of said stores and said facility; recurrently detecting the presence of activity and inactivity in said line circuits; storing indications of said activity and inactivity in ordered association with said respectively paired stores; recurrently assigning up to m of said stores for transmissive coupling, via up to m of said channels, with respective said destination lines; and conditioning the selection of said up to m stores for said channel assignments upon said respective stored activity indications. - View Dependent Claims (9, 10, 11, 12, 13)
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Specification