A sequential data packet addressing technique and system, particularly adapted for shared memory output-buffered switch fabrics and related memories, using a ring of successive subaddress generators each assigning addresses for predetermined size data byte packets received in successive time slots, and creating therefrom super packets ordered based on arrival time; and sequentially allocating memory therefor in the shared memory without overlap among the packets and with no holes between adjacent packets, and assigning addresses for the individual packets in the super packets upon the assigning of an address in the memory for each super packet.

A method of making conference call connections in computer-controlled telephone exchanges includes combining voice signals of conference participants on a digital basis, forming a signal of a total of speaking levels of a given number of the most active participants, distributing the signal in an undamped manner, and suppressing voice signals of the inactive participants. A bit stream of the conference participants reaching a conference assembly through an incoming line is distributed to m adding processors having n channels each, and the PCM words are linearized with a code table and stored in level memories for each particular participant. A total of the linear values is formed, is added to individual participant evaluation totals and is stored in evaluation memories for each particular participant. The participant evaluation totals are transmitted to an evaluation processor which determines active channels by using a delayed mean value of the participant levels and transmits it to the adding processors. A conference total signal is created by adding linear values of all channels. Transmission signals for all channels are formed in the adding processors by compressing the conference total signal, the individual linear value of the active participants being substracted before compression. The signals thus created are stored in transmitting memories and transmitted through an outgoing line.

A hub-resident data switching apparatus for a multinode teleconferencing network enables plural node sites, operating at differing clock rates, to communicate with each other asynchronously and simultaneously. The switching apparatus includes an internal TDM bus to which plural node interface units, an audio combiner unit and a timing and control unit are coupled. Each node interface unit is associated with a respective node and is operative to receive and forward communication signals with respect to its node at the clock rate of the service used by that node. The hub's TDM bus includes a video/PC file bus and an audio/command bus and operates at a clock rate that is a multiple of the number of nodes in the network times the highest clock frequency of any node in the network divided by the bit width of the TDM bus. Each unit interfaces with the TDM bus by way of a pipeline bus interface unit. The audio combiner unit outputs digitized `combined audio` signal packets onto the audio bus for transmission to its associated node. The output section of the audio combiner unit includes an audio packet input buffer whose contents are processed in dependence upon the occupancy status of each audio packet input buffer in the combiner. As long as there is sufficient audio data stored in one or more buffers to ensure effectively continuous audio processing, audio data is processed and forwarded for transmission. If the audio packet input buffers have very little or no audio data, then processing is delayed.

The kind of medium owned by a user is stored in a service center system and a medium is determined by a request from the transmitting side in accordance with an inquiry to a receiver. Where a voice is used as a medium for the inquiry or the service, the sound piece data to which a descriptor is added and the sentence structure data for forming a single sentence by collecting the sound piece data and formed by a descriptor are stored. When the voice output request is produced, the sound piece data is obtained from the sentence structure data, thereby producing a voice of a desired sentence.

A compact and low-cost multiplexing apparatus for a plurality of high-efficiency encoded image signals is capable of improving an image quality and of shortening a transmission delay time. The multiplexing apparatus for an image signal includes delay compensating circuits provided corresponding to a plurality of image terminals, for storing image encoded signals sent from the respective image terminals; a control circuit for performing a control to form a large frame signal from small frame signals whose number is equal to at the most the number of image signal sources, by detecting frame head codes from input/outputs of the delay compensating circuits, thereby not being duplicated from a plurality of delay compensating circuits, and also adding circuit for adding a frame start code to each of large frames. Even when the frame rates are different between terminals, since all of the image encoded signals are not decoded but multiplexed, deterioration of image qualities and transmission delays can be reduced. Since apparatuses for encoding/decoding images can be omitted, the entire multiplexing apparatus can be made compact.