A digital teleconferencing control device, system and method for use in telecommunications. A digital conference control circuit having pulse code modulation and time division multiplexing is used in connecting a plurality of telephone subscribers (14) together for conference purposes. When so connected, a plurality of then selected speakers can be heard by all other subscribers connected into the conference with the number of subscribers connectable into the conference being unlimited. Logic gates (28, 38) at the digital level in the control circuitry prevents return of signals generated by a speaking subscriber back to that subscriber.

Digital teleconferencing control device, system and method

An apparatus and a method of conference and handling of telephone information helps to have a plurality of input calls with access to one or more groups or combinations of permanent or new communications. The device generally has an input element (12, 64) for receiving calls on the incoming lines and has switching elements (16, 70, 72) for connecting each of the incoming lines in a group conferences. Generally, an operator controls the arrival of calls to the needs and functions, and directs calls to consolidation or group conversations available. The operator controls the overall operation of the device and provides information as needed. An apparatus (161) to control the voice power level on arrival lines allows the identification of the caller and allows the recording of the views of people calling, that is to say the votes. reaction audible confirmation signals assure the caller that their vote was recorded. New subscribers, or limits or restricted subscribers can have access to the system on a control basis, and can listen groupings or "pools" of ongoing conversations, but they can not talk with other members of the "pool" .

Telephone-conferencing apparatus and method

An improved (N - 1) adding operation conference telephone communication method through an electronic exchange in which the telephone communication signals on speakers in a time sharing multiplexed telephone communication path are added, the telephone communication signal on any particular speaker is subtracted and the resulting telephone communication signals are transferred to the remaining respective speakers. The levels of the telephone communication signals are monitored which are obtained as the result of the (N - 1) adding operation. When the telephone communication signals exceed a preset threshold level, they are selectively attenuated and transferred to the remaining respective speakers. The selective attenuation of the telephone communication signals which have exceeded the threshold level is released a predetermined time after conditions under which the threshold level is exceeded have disappeared to thereby prevent satisfactorily the deterioration of the voice quality which would otherwise be feared.

Electronic exchange having a conference telephone communication function and conference telephone communication method

A method for transmitting equipment-specifying program parameter data from a communications installation to communications terminal equipment. The method provides for transmitting program parameter data from a communications installation to a plurality of communications terminal equipment connected thereto and is based on a message-oriented transmission protocol that is used in the sense of an information exchange in the signalling channel between the equipment. In the communications equipment, the input and output devices as well as the procedures of performance features and local performance features are essentially controlled with the assistance of the program parameter data. A transmission of program parameter data is initiated either by a parameter request message transmitted from the communications terminal equipment or by an internal request of the communications installation. In a start of parameter message, address and parameter defining criteria are transmitted from the communications installation to the respective communications terminal equipment. Subsequently, the program parameter data embedded into a parameter message are transmitted to the respective communications terminal equipment and are stored in them.

Method for transmitting terminal-specifying program parameter data from a communications installaton to communications terminal equipment

A three-party conference circuit provides for three-party conference calls in time-division-multiplex communication systems utilizing pulse-code modulation. The digitized speech signals from a selected group of channels are received from an incoming PCM highway, expanded from PCM coding to linear coding and consecutively stored in groups of three in three registers. Different pairs of the registers are selected by a multiplexer, after which the speech signals from the selected pairs of registers are added to provide a combined speech signal. The combined speech signals are compressed from linear coding to PCM coding and applied to an outgoing PCM highway for transmission to the respective parties. Since the speech signals are combined and retransmitted essentially within the same frame, time delay distortion of the audio signals is minimized. In addition, the three-party conference circuit provides for a diagnostic mode of operation where incoming speech signals are retransmitted and a broadcast mode of operation where the speech signals from one channel are combined with each of the other channels of the selected group of channels to be transmitted.

Three-party conference circuit for digital time-division-multiplex communication systems

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.

Lejay Augustin

Papers

Conference circuit using PCM techniques