Apparatus and method for establishing crypto conferences on a telecommunications network

A telecommunication system

• a plurality of conferencing nodes (2-9) including one or more speaking nodes for providing a speaking signal and listening nodes, each listening node responsive to a switched speaking signal;
• and
• conference call connection means (10), responsive to the speaking signal, for providing the switched speaking signal to all the listening nodes except the speaking node;
• wherein each of the plurality of nodes has a pair of first and second channels (B1 B2);
• wherein the conference call connection means (10) has at least two resource buses (11, 12) and a matrix (M) for providing the speaking signal to the listening nodes but not the speaking node;
• wherein each node has its first and second channels (B1, B2) connected to the connection means (10) so the speaking node can transmit a first speaking signal on the first channel (B1) and can receive a second speaking signal on the second channel (B2) from another speaking node.

A telecommunications system, which is an Integrated Service Digital Network (ISDN) comprising:

• a plurality of conferencing nodes (2-9) being arranged in two one-way conference rings with a pair of first and second channels (B1 B2), each of the plurality of nodes having a pair of adjacent nodes in the ring;
• the nodes including a speaking node for providing a speaking signal on a channel, and further including listening nodes, each listening node responsive to a switched speaking signal;
• and
• conference call connection means (15), responsive to the speaking signal, for providing the switched speaking signal to all listening nodes, the conference connection means (15) receiving the switched speaking signal back from each listening node and providing it to a next adjacent listening node in the ring;
• the conference connection means (15) providing the speaking signal to the speaking node that generated it after providing it to all the listening nodes, the speaking node deleting the speaking signal from the conference ring and releasing the channel for use by other speaking nodes.

A telecommunication system, which is an Integrated Service Digital Network (ISDN) comprising:

• a plurality of conferencing nodes (2-9) being arranged in two one-way conference rings with a pair of first and second channels (B1 B2), each of the plurality of nodes having a pair of adjacent nodes in the two respective conference rings;
• the nodes including a speaking node for providing a speaking signal on a channel, and further including listening nodes, each listening node responsive to a switched speaking signal;
• and
• conference call connection means (15), responsive to the speaking signal, for providing the switched speaking signal to all listening nodes, the conference connection means (15) receiving the switched speaking signal back from each listening node and providing it to a next adjacent listening node in the ring;
• the conference connection means (15) providing the speaking signal to the speaking node that generated it after providing it to all the listening nodes, the speaking node deleting the speaking signal from the conference ring and releasing the channel for use by other speaking nodes;
• wherein each node includes decryption means (31,36) for decrypting an incoming speaking signal and decryption means (36,37) for encrypting an outgoing speaking signal;
• wherein each node includes data communications means (32,34) adapted for including and excluding the node in the conferencing ring;
• wherein each node includes switching means (33) either for looping incoming speaking signals on one channel (B1) as outgoing speaking signals on another channel (B2), or for looping incoming speaking signals on one channel (B2) as outgoing speaking signals on another channel (B1).

Method to establish a speech conference connection between a group of conference participating nodes (2,4,8) which can freely be selected among a greater plurality of nodes (2-9) having conference facilities, and which can be interconnected by at least one telecommunication network (1) having at least one switching exchange (10) for establishing at least one conference ring,

• wherein each node may be mutually interconnected via the switching network (1) such as a switched telecommunication network to transmit and receive information, the nodes (2-9) arranged so that each and every node (2) among a freely selected group (2,4,8) of participating nodes may send information to all the remaining participating nodes (4-8), and the switching exchange (10) having at least one ring configuration, each node (2,4,8) with conferencing facilities, further incorporates decoupling devices (30, 41, 46, 49) which recognizes and detects the locally generated signal when it returns to its transmitting node, and as a response to this recognition breaks the ring at the input to this node and thus generates a dynamically broken ring configuration;
• wherein the number of dynamically broken ring connections present in the system are lower than or equals the number of nodes which participates in the established group, and each node comprises an accessing means which within a certain time interval may access any one of the transmission resources, assuming that the resource in question, is free in this time interval;
• wherein the system further comprises a preference system which operates so that when more than one participating nodes are trying to obtain access to the same channel at the same time interval, only the participant with the highest preference will succeed;
• and
• wherein each node comprises a random number generator so that each attempt by an node to access a free transmission resource is assigned a random number generated locally in that node and is available for any other node listening to this free transmission resource, a highest priority and thereby the free transmission resource preferably being given to a participant according to the assigned random number;
• the method including the steps of:
• providing conference participating nodes with completely identical designs so that each node (2,4,8), can perform all signal processing including amplification and speech-coding/decoding in a decentralized manner, while routing and switching of information takes place in the at least one network exchange (10);
• connecting all the conference participating nodes (2,4,8) in series in a conference ring, which only includes these conference participating nodes (2,4,8) for each new conference ring to be established;
• sending a digitally represented sound information from an active sending node as one of the conference participating nodes (2,4,8) to other conference participating nodes;
• subjecting the digitally represented sound information to no other signal processing than ordinary copying in each node;
• circulated the digitally represented sound information in the conference ring before it returns back to the active sending node;
• and
• deleting the digitally represented sound information in the active sending node so the conference ring is terminated.