Conference circuit using PCM techniques
AssigneeInternational Standard Electric Corporation
InventorAugustin LeJay
Life of this patent
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Abstract
Conference circuit which uses a read/write memory divided into groups of memory lines, with each group corresponding to a conference. Each line is assigned to store data from a single subscriber and to store the code words coming from that subscriber. The memory stores non-linear subscribers' codes. The codes are expanded and the codes of other subscribers in the same conference are added and compressed for transmission and decoding at any other exchange of other conference members. The conference circuit may be inserted in one position of a group of junction circuits or may be placed in a subscriber line concentrator.
Claims5
A conference circuit for interconnecting plural subscribers within a PCM switching network having a predetermined frame repetition rate comprised of a plurality of successive time slots, the invention including:
- memory means for storing non-linear coded data received from subscribeers during time slots allotted to the respective subscribers, expander means receptive of coded data received from said memory means, for expanding the received data, adder means for receiving expanded data and for combining the expanded data with data fed back from the output of the adder means, and further means for compressing linear data received from the adder means, wherein said memory means comprises a read/write memory comprised of a memory line for each subscriber served, the lines of said memory means being grouped into plural groups of consecutive time slots with the number of groups corresponding to the number of simultaneous conferences possible and the number of lines per group corresponding to the maximum number of subscribers per conference, means for writing into said memory means at the rate of one line per time slot, and means for successively reading the lines of an entire group during one time slot.
Dependencies are inferred from the claim text.