Broadcast Conferencing Arrangement

This invention relates to communication systems and particularly to conference arrangements and methods in which a transmitting conferee generates signals that are received by other conferees.

In a communication network it is often desirable to provide conference circuits service whereby a plurality of customers who are geographically separated can all simultaneously receive communication signals generated by one of the conferees. On such conference arrangement is disclosed in U.S. Pat. No. 4,635,251 issued to K. R. Stanley et al. In this arrangement a telephone number for accessing a conference bridge is given to the conferees and a separate number is given to a host conferee who controls the conference call. Each of the conferees can be attached to the conference bridge by dialing or keying the appropriate number.

While such arrangements are suitable for audio conferences in which audio signals from several conferees may be meaningfully combined for dissemination to all conferees, they are less suitable for conferences in which data or video signals generated by one conferee are to be transmitted to the other conferees. The arrangements are also unsuitable for use with customer stations which generate video or data signals outside the telephone audio band that cannot be readily switched through local switching systems. A problem of the prior art therefore is that no satisfactory arrangement exists for providing dialed, using a rotary dial or keys, one-way broadcast arrangements, especially for transmitters and receivers using signals outside the telephone audio band.

The aforementioned problem is solved and a technical advance is achieved in the art by providing a transmitting customer station of a broadcast connection with a first telephone number for accessing the incoming port of a broadcast bridge and providing each of the receiving customer stations of that broadcast connection with a second telephone number for accessing one of the outgoing ports on the same broadcast bridge whereby, advantageously, whoever first dials the telephone number for accessing the incoming broadcast port becomes the transmitter of the broadcast until that customer relinquishes the incoming port by disconnecting. Advantageously, another customer station can then dial the telephone number for accessing the incoming broadcast port and become the transmitting station, and the former transmitting customer station can then dial the second telephone number for joining the broadcast conference as a receiver.

In one specific embodiment, translations for converting a broadcast access code to a broadcast terminal number are shared among many switching systems of a switched network so that access to broadcast bridges may be controlled from a central source. Advantageously, a particular set of conferees is not allowed access to such a broadcast bridge indefinitely. Advantageously, the security of broadcast bridge access directory numbers can be maintained.

In accordance with one aspect of the invention, customers with highspeed (56 Kbit/sec) transmitting and receiving stations are connected directly to toll switching systems, bypassing local switching systems. Advantageously, such an arrangement provides a dedicated facility for transmitting signals to a toll switching system without encountering an increased error rate, which is introduced in switching high-speed signals through local switching systems. Further, local switching systems for switching such high-speed signals are very sparsely deployed at this time.

In accordance with one aspect of the invention, answer supervision is automatically returned to a transmitting broadcast conferee by connecting that conferee to a digital service unit whose request to send lead is permanently strapped to the receive line/signal detect lead of that unit. This provides answer supervision to the toll switching system connected to the transmitting broadcast customer station conferee to allow charging to begin.

In accordance with one specific embodiment of the invention, a dedicated time slot interchange unit is used as a broadcast bridge to broadcast a digital signal from a transmitting broadcast customer station to each of the receiving broadcast customer stations. Advantageously, such an arrangement replicates the transmitted signal to each of the receiving broadcast customer stations at low cost.

The invention will be better understood from the following detailed description when read with reference to the drawing in which:

FIG. 1 is a system block diagram showing connections for a broadcast call; and

FIG. 2 is a flow diagram of the steps for setting up such a call.

FIG. 1 is a block diagram of one embodiment of the invention. Shown are a transmitting station 1 for generating a video signal or data signal to be transmitted to each of the receiving broadcast conferees. Also shown is a receiving station 2, one of a plurality of receiving broadcast conferees. Dedicated time slot interchange (DTSI) 8 is used as a broadcast bridge to transmit the incoming signal on a one-way incoming port 30 to outgoing signals on one-way outgoing ports 31,32,33, . . . ,3N. A customer at transmitting station (transmitter) 1, which is directly connected to a toll switch 4, dials a broadcast transmitter access code 700-561-1234. The first five digits are dedicated to the broadcast service, the last five digits are assigned to a specific customer for a particular block of time. Toll switch 4, which in this case is an action control point (ACP), requests a translation from network control point (NCP) 3 by sending the dialed number 700-561-1234 and receives action point number (APN) 872-102-2468. Toll switch 4 is a 4 ESS.TM. switch described in "NO. 4 ESS", Bell System Technical Journal, Vol. 56, No. 7, pp. 1015-1320, September 1977, and "No. 4 ESS", Bell System Technical Journal, Vol, 60, No. 6, pp. 1041-1224, July-August 1981. The APN is used for routing the call to service node 6 which is a toll switch provided with one or more DTSI's. The APN is used within service node 6 by processor 9 to access Routing Table 20 for accessing input port 30 of DTSI 8. The appropriate ports of DTSI 8 are reserved for the proper time period by setting up data in NCP 3. The data in Table 20 for translating from an APN to a port or group of ports can be more permanent, since access to these ports is controlled at NCP 3 by limiting the time that a particular access code is translated to the action point number for reaching the broadcast bridge. The role of action control points, network control points, and the common channel interoffice signaling network interconnecting these units, is described in The Bell System Technical Journal, Vol. 61, No. 7, Part 3, September 1982, pp. 1573-1803, which describes the general principles of the stored program controlled network. Before this call was received, telephone operating personnel had assigned an access number 700-561-1234 as the transmitting number for accessing the input port, and a corresponding number 700-562-5678 for accessing outgoing ports of DTSI 8, to these customers for a particular block of time to allow these customers to utilize the broadcast conference service during that time. Advantageously, since the numbers were only given to these customers, others are prevented from dialing a number to receive the broadcast signals. While the embodiment described herein uses a public switched network, a private switched network could also be used.

An APN is an internal routing number of the same format as a conventional POTS (Plain Old Telephone Service) customer number, but is readily recognizable, in this case, by the fact that digits 4-6 are not in the range of POTS central office codes, all of which have an initial digit in the range of 2-9. If a customer tried to call an APN, the number would be screened and rejected at ACP 4. APN 872-102-2468 is used by action control point 4 to route a call from transmitting station 1 to service node 6 which includes switching network 7 for switching the call signals from transmitting station 1 via a group of circuits 10-13 whose purpose will be discussed infra, to input port 30 of broadcast conference bridge DTSI 8. In the meantime, a customer at receiving station (receiver) 2 has dialed 700-562-5678 into the ACP 5 to which receiver 2 is connected. Action control point 5 requests a translation from network control point 3 and receives a second APN 872-102-2469 which is used for accessing one of the output ports, in this case 33, of DTSI 8. Receiving station 2 is connected via ACP 5 to service node 6, and therein, through switching network 7 to output port 33 of DTSI 8. At this time, transmitter 1 is transmitting signals to receiver 2 and any other receivers connected to one of the ports 31,32,33, . . . ,N. If transmitter 1 has completed transmitting its broadcast message, the customer at that transmitter disconnects and, if desired, reconnects as a receiver by dialing 700-562-5678.

Direct digital access-office channel unit (DDA-OCU) 10 is a commercially available channel unit connectable to a time slot interchange unit of a 4 ESS switch. DDA-OCU provides an output for connection to a commercially available digital signaling unit 1 (DSU1). By connecting a lead designated as the request to send (RTS) lead of OSU1 to a lead designated as the receive line/signal detect (RS/SD) lead, answer supervision is automatically returned to transmitter 1 when DSU1 receives a seizure signal. DSU2 is connected back-to-back to DSU1 to provide an output for driving a commercially available office channel unit-data port (OCU-DP) 13 which is connected to an input port of DTSI 8.

While this embodiment illustrates arrangements in which ports of a DTSI are reserved for a block of time for a specific group of customers, it is also possible to have an engineered group of DTSI's and ports and to assign customer groups to these ports at the beginning of a broadcast call by having a flexible translation in Table 20 to translate from a broadcast bridge APN to an available broadcast bridge of a group of such bridges, and then select an input broadcast port or one of a group of output broadcast ports within that bridge for the broadcast conferees identified by one pair of APN's.

FIG. 2 is a flow diagram of the steps for setting up a broadcast call in accordance with the principles of this invention. First, the data base of NCP 3 must be initialized with the assigned transmitting station and receiving station numbers to allow subsequent translations to be performed between these assigned numbers and the internal routing numbers, i.e., the action point numbers, necessary for routing the call to the ports of a broadcast bridge (action block 100). At some later time, the transmitting station dials the assigned transmitting station number (action box 102) and is routed to an action control point. The action control point accesses the data base of network control point 3 to translate the assigned transmitting station number to the action point number which is the number used internally within the public switched network to route the call from the transmitting station to the input port of the broadcast bridge (action box 104). The transmitting station is then connected to the input port of the broadcast bridge (action box 106). The receiving stations each dial the assigned receiving station number (action box 108). They are each then connected to an action control point which accesses the data base of network control point 3 to translate the assigned receiving station number to a number used internally in the public switched network to access the group of output ports of the broadcast bridge (action box 110). Each receiving station is then connected to one port of that output port group (action box 112).

It is to be understood that the above description is only of one preferred embodiment of the invention. Numerous other arrangements may be devised by one skilled in the art without departing from the spirit and scope of the invention. The invention is thus limited only as defined in the accompanying claims.