WO2000033531A2

WO2000033531A2 - Isolated connection in a multiparty call

Info

Publication number: WO2000033531A2
Application number: PCT/SE1999/001968
Authority: WO
Inventors: Alex Goldberg; Richard Gagnon; Claude Gauthier
Original assignee: Telefonaktiebolaget Lm Ericsson (Publ)
Priority date: 1998-11-30
Filing date: 1999-11-02
Publication date: 2000-06-08
Also published as: WO2000033531A3; AU1433000A

Abstract

A system, method, and apparatus for establishing a multiparty call isolating one or more parties (110) is presented. Input signals are received from each of the parties at an unrestricted party accumulator (215). The output of the unrestricted party accumulator is transmitted to each party (110b, 110c) except the restricted party(s) (110a). Input signals are received at a restricted party accumulator (220) from each party except the party(s) which the restricted party(s) is restricted from hearing. The output of the restricted party accumulator is received by the restricted party(s) (110a).

Description

ISOLATED CONNECTION IN A MULTIPARTY CALL

BACKGROUND OF THE INVENTION

Technical Field of the Invention

The present invention relates to multiparty telephone calls and, in particular, to the monitoring of a phone call by a third party. Description of Related Art

Third party monitoring of phone calls is well known in the art. In one scenario, a third party such as a law enforcement agency monitors a phone call via a connection between a telecommunications switch and a monitoring center known as a "tap J Each telecommunication switch in the network is programmed with a stored list of telephone numbers assigned to subscribers whose calls are to be monitored. Whenever a switch handles a call connection having a calling party or called party identification number matching a number on the stored list, the switch establishes a tap connection with the monitoring center. Conventionally, the monitoring party is unable to communicate with any of the parties to the telephone call. However, in certain situations, one or more parties to the telephone call may be the law enforcement agency or a person cooperating with the law enforcement agency, and in such situations it may be beneficial for the monitoring party to communicate with the party to the phone call which is, or is cooperating with, the law enforcement agency.

In another monitoring scenario, a three-way call can be established between the cooperating party, the investigated party and the monitoring party. Monitoring a telephone call using three-way calling is easily effectuated using a widely available subscriber service feature. Three-way calling allows the monitoring party to communicate with the cooperating party. However, the communications by the monitoring party are also heard by all of the other parties to the telephone call. There exist many situations where it would be beneficial if the monitoring party's side of the communication were not heard by all of the other parties to the call.

Accordingly, it would be advantageous if a mechanism could be provided for specifying that the monitoring party be able to participate in the telephone conversation but not be heard by other parties to that conversation. The foregoing would be useful in many situations besides the law enforcement context. For example, the customer service representative in training may receive assistance and directions from a supervisor while responding to an inquiry by a customer. In the foregoing situation, the customer service representative in training and the supervisor may not wish for the customer to hear the communications made by the supervisor.

SUMMARY OF THE INVENTION The present invention is directed to a system, method, and apparatus for establishing a multiparty telephone call wherein one party does not hear communications from another party to the call. Input signals are received from each of the terminals at an unrestricted party accumulator. The output of the unrestricted party accumulator is then transmitted to each party except for the restricted party(s). Input signals are simultaneously received at a restricted party accumulator from each party except the party(s) which the restricted party(s) is restricted from hearing. The output of the restricted party accumulator is then transmitted to each of the restricted party(s).

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosed invention is described with reference to the accompanying drawings which illustrate sample embodiments of the invention and which are incorporated in the specification hereof by reference, wherein:

FIGURE 1 is a block diagram of a telecommunications network; FIGURE 2A is a block diagram of a telecommunications switch embodying the present invention;

FIGURE 2B is a block diagram of the telecommunications switch implementing an exemplary multiparty call with an isolated connection;

FIGURE 3 is a flow diagram illustrating the operation of an application module to provide a multiparty call with an isolated connection in accordance with the principals of the present invention;

FIGURE 4 is a flow diagram illustrating the operation of the application module establishing an isolated connection in a multiparty call by a party engaged in a phone call with a first party that receives an incoming call from a third party; and FIGURE 5 is a flow diagram illustrating the operation of the application module establishing a multiparty phone call from a calling party wherein all parties hear communications from each other at one point, and during the course of the conversation, restricting one party from hearing the communications of another party.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to FIGURE 1, there is shown a block diagram of a telecommunications network 100. The telecommunications network 100 comprises a network of telecommunications switches 105a, 105b, 105c each serving a plurality of telephone terminals 110. The telecommunications switch 105 comprises, for example, a local exchange or a mobile switching center. Where the telecommunications switch is a local exchange, the telephone terminal 110 comprises wireline telephonic equipment such as a wireline telephone or a computer or fax machine with either a wireline modem or an ISDN connection. Where the telecommunications switch 105 comprises a mobile switching center, the telephone terminal 110 comprises wireless telephonic equipment such as a mobile station or a computer or fax machine with a wireless modem connection. Each telephone terminal 110 is in communication with a particular telecommunications switch 105 via a communication channel 115. The communication channel 115 comprises either a land based telephone line where the telecommunications switch 105 is a local exchange or a wireless air interface where the telecommunications switch comprises a mobile switching center or a base station. When a subscriber of telephone 110a wishes to initiate a call to a subscriber at telephone terminal 110b, telephone terminal 110a communicates a directory number associated with telephone terminal 110b to the serving telecommunications switch 105a over communications channel 115a. In a manner well known in the art, telecommunications switch 105 a ascertains the telecommunications switch 105b which is associated with telephone terminal 110b. Telecommunications switch 105a and telecommunications switch 105b then coordinate to establish a voice connection between telephone terminal 110a and telephone terminal 110b. The voice connection comprises the communication channel 115a, a trunk connection 120 connecting telecommunications switch 105a and communications switch 105b and communications channel 115b.

Systems and methods for monitoring a call between telephone terminals 110a and telephone terminal 110b are well known in the art. In one scenario, a tap in one of the telecommunications switches, e.g., switch 105b, establishes a connection between a monitoring center 125 and the voice connection between telephone terminal 110a and telephone terminal 110b. The foregoing is disadvantageous because the monitoring party at the monitoring center 125 is unable to communicate to the subscriber at telephone terminal 110a or telephone terminal 110b. In another scenario, a subscriber at telephone terminal 110b can establish, using a subscriber feature well known in the art, a three-way call between themselves, a subscriber at telephone terminal 110a and the monitoring party at a telephone terminal 110c. Although the foregoing allows the monitoring party at telephone terminal 110c to communicate during the call, any communication by the monitoring party is heard by both the subscriber at telephone terminal 110a and the subscriber at telephone terminal 110b. There exist many situations where it would be beneficial if the monitoring party's side of the communication were not heard by all of the other parties to the call. In order to allow the monitoring party at telephone terminal 110c to selectively communicate with some but not all of the parties to the call, the present invention proposes making a modification to the operation of a call conferencing device within the telecommunications switch 105.

Referring now to FIGURE 2A, there is shown a block diagram of a telecommunications switch 105 embodying the present invention. The telecommunications switch 105 comprises a Group Switch/Time Switch (GS/TS) 201 controlled by a controller 202 which receives and interfaces communications channels 115 and trunk connections 120. The GS/TS 201 selectively connects a particular communication channel 115 and a particular trunk connection 120, thus establishing a bidirectional voice connection. During a multiparty call, the controller 202 causes the GS/TS 201 to input the communication channel 115 and the trunk connections 120 associated with the call to one of several call conferencing devices (CCDs) 210 to establish the multiparty call. A CCD 210 is used to allow parties to speak to and listen to the other parties of the multiparty call. The CCD 210 includes a plurality of accumulators, including an unrestricted party accumulator 215 and a restricted party accumulator 220. Audio signals are received from each telephone terminal 110 participating in the call at an accumulator - such as the unrestricted party accumulator 215 or the restricted party accumulator 220.

An accumulator such as unrestricted party accumulator 215 or restricted party accumulator 220 receives audio signals representing communications from subscribers from any number of telephone terminals 110. The contents of the accumulator are read and can be selectively transmitted to a particular telephone terminal 110 minus the audio signals received from the particular telephone terminal 110.

Referring now to FIGURE 2B, a block diagram of the telecommunications switch 105b implementing an exemplary multiparty call with an isolated connection is illustrated. The telecommunications switch 105 permits ( 1 ) a subscriber at telephone terminal 110b (party B) to engage in a call with a subscriber at telephone terminal 110a (party A), (2) a subscriber at telephone terminal 110c (party C) to monitor the call, and (3) party C to communicate with party B without the communications being heard by party A. The foregoing can be implemented as a subscriber feature that is effectuated by an application module 205 executed by the controller 202. The controller 202 causes audio signals received from parties A, B, and C to be input from the GS/TS 201 to the unrestricted party accumulator 215. An output of the unrestricted party accumulator 215 is transmitted to party B representing the combined and mixed audio signals received from party A, party B, and party C. Similarly, an output from the unrestricted party accumulator 215 is transmitted to party C representing the combined and mixed audio signals from party A, party B, and party C. Party A does not receive an output from the unrestricted party accumulator 215, thus preventing party A from hearing communications by party C. Party A, on the other hand, receives an output from the restricted party accumulator 220. The inputs to the restricted party accumulator 220 include all of the parties to the multiparty call except the parties which party A is not supposed to hear (e.g., party C). Accordingly, the output of the restricted party accumulator 220 includes the audio signal received from party A and party B but does not include audio signals from party C. With the present invention, party C can monitor a call between party A and party B and communicate with party B without that communication being heard by party A. It is noted that the component of a party's own contribution to the signal output from the accumulator is suppressed or otherwise accounted for in delivering the output signal to that party.

Referring now to FIGURE 3, there is shown a flow diagram illustrating the operation of the application module 205 in accordance with the principles of the present invention. At step 305, a call is established between a first telephone terminal and a second telephone terminal. At step 310, a hook flash is received followed by a directory number associated with a third telephone terminal and one of two unique subscriber feature codes. The telecommunications switch then establishes a call between the second telephone terminal and the third telephone terminal (step 315). After the call is established, the application module determines whether the party at the second telephone terminal has hook flashed back (step 320). If the party at the second terminal has hook flashed back, the application module determines whether one of two particular subscriber codes were received (step 322). The first particular subscriber code indicates that the party at the first terminal is not supposed to receive communications from the third telephone terminal. The second particular subscriber code indicates that the party at the third terminal is not supposed to receive communications from the first telephone terminal. If the party at the second terminal has not hook flashed back at step 320, the application module waits to receive a hook flash back (step 321) before performing step 322.

If at step 322, the application module did not receive one of the two particular subscriber codes, the application module proceeds to establish a conventional multiparty call between the first, second, and third telephone terminals where each party can hear all of the other parties (step 325). If at step 322, the application module 205 did receive one of the two particular subscriber codes, the signals from each telephone terminal are input to the unrestricted party accumulator (step 330). At step 335, the accumulator causes an output of the unrestricted party accumulator to be transmitted to the second telephone terminal. The accumulator then causes the signals received from the second telephone terminal to be input to the restricted party accumulator (step 340). At step 345, the accumulator determines whether the subscriber at the first telephone terminal is supposed to received communications from the subscriber at the third telephone terminal, based on the subscriber feature code received during step 322. Where the subscriber at the first telephone terminal 110a is not to receive communication from the third telephone terminal, the application module 205 inputs the signals received from the first telephone terminal to the restricted party accumulator (step 350), transmits the output of the restricted party accumulator to the second telephone terminal (step 355) and connects an output of the unrestricted party accumulator to the third telephone terminal (step 360). Thereby, the subscriber at telephone terminal can monitor the call between the first telephone terminal and the second telephone terminal, and communicate with the subscriber at the second telephone terminal without being detected by the subscriber at the first telephone terminal. If during step 345 the subscriber at the first telephone terminal is supposed to receive communications from the third telephone terminal, the application module inputs the signals received from the third telephone terminal to the restricted party accumulator (step 365), transmits the output of the restricted party accumulator to the third telephone terminal (step 370) and connects an output of the unrestricted party accumulator to the first telephone terminal (step 375). Thereby, the subscriber at first telephone terminal can monitor the call between the second telephone terminal and the third telephone terminal, and communicate with the subscriber at second telephone terminal without being detected by the subscriber at the third telephone terminal.

The foregoing provides a method wherein a subscriber engaged in a telephone call with a first party can call a third party and selectively restrict one of the parties from hearing communications by the other party. Alternatively, an isolated connection in a multiparty call can be achieved by a party engaged in a phone call with a first party that receives an incoming call from a third party.

Referring now to FIGURE 4, there is shown a flow diagram illustrating the operation of the application module establishing an isolated connection in a multiparty call by a party engaged in a phone call with a first party that receives an incoming call from a third party. At step 405, a call is established between a first telephone terminal and a second telephone terminal. An incoming call is received by the second telephone terminal from the third telephone terminal (step 410), and the subscriber at the second telephone terminal hook flashes to accept the incoming call from the third telephone terminal (step 415). At step 420, one of two unique subscriber feature codes is received by the subscriber at the second telephone terminal followed by a hook flash back (step 425). The first of the two unique subscriber codes requests an isolated connection multiparty call wherein the party on hold is restricted from hearing communications from the other party. The second unique subscriber code requests an isolated connection multiparty call wherein the other party is restricted from hearing communications from the party on hold.

After the subscriber at the second telephone terminal hook flashes back, the signals from the first, second, and third telephone terminals are input to the unrestricted party accumulator (step 430). At step 435, the application module causes an output of the unrestricted party accumulator to be transmitted to the second telephone terminal. The application module then causes the signals received from the second telephone terminal to be input to the restricted party accumulator (step 440). At step 445, the application module 205 determines whether the subscriber at the first telephone terminal is supposed to receive communications from the subscriber at the third telephone terminal based on the received subscriber feature code in step 425.

Where the subscriber at the first telephone terminal is not to receive communication from the third telephone terminal, the application module inputs the signals received from the first telephone terminal to the restricted party accumulator (step 450), transmits the output of the restricted party accumulator to the first telephone terminal (step 455) and connects an output of the unrestricted party accumulator to the third telephone terminal (step 460). Thereby the subscriber at the third telephone terminal can monitor the call between the first telephone terminal and the second telephone terminal, and communicate with the subscriber at the second telephone terminal without being detected by the subscriber at the first telephone terminal.

If during step 445 the subscriber at the first telephone terminal is supposed to receive communications from the third telephone terminal, the application module inputs the signals received from the third telephone terminal to the restricted party accumulator (step 465), transmits the output of the restricted party accumulator to the third telephone terminal (step 470) and connects an output of the unrestricted party accumulator to the first telephone terminal (step 475). Thereby, the subscriber at the first telephone terminal can monitor the call between the second telephone terminal and the third telephone terminal, and communicate with the subscriber at the second telephone terminal without being detected by the subscriber at the third telephone terminal.

The foregoing provides a method wherein a subscriber can establish a multiparty call wherein a one party is restricted from hearing communications from another party. It is recognized, that a subscriber may desire to establish a multiparty phone call where all parties can hear communications from each other at one point, and during the course of the conversation, one of the parties may wish to communication with the subscriber and restrict another party from hearing the communication.

Referring now to FIGURE 5, there is illustrated a flow diagram of the operation of the application module 205 establishing a multiparty phone call from a calling party where all parties can initially hear communications from each other, and where one party is restricted from hearing the communications of another party during the phone call. At step 505, amultiparty call between a first telephone terminal 110a, a second telephone terminal 110b, and a third telephone terminal 110c is established. As the course of the telephone conversation proceeds, the subscriber at third telephone terminal 110c wishes to restrict either the first or the second telephone terminal from hearing communications from the first telephone terminal, and hook flashes and enters one of two particular subscriber feature codes. The first of the particular subscriber feature codes indicates that the third party would like to restrict the first party, while the second particular subscriber code indicates that the third party would like to restrict the second party. Responsive to receiving and detecting the hook flash from third telephone terminal (step 510), the application module inputs signals from the first, second, and third telephone terminals to the unrestricted party accumulator (step 515), transmits an output from the unrestricted party accumulator to the third telephone terminal (step 520), and inputs signals from the first and second telephone terminals to the restricted party accumulator (step 525).

At step 530, the application module determines whether the first party is to be restricted based on the subscriber feature code received during step 510. If the first party is to be restricted based on the subscriber feature code received during step 510, the output of the unrestricted party accumulator is transmitted to the second telephone terminal (step 535) and the output of the restricted party accumulator is transmitted to the first telephone terminal (step 540). If during step 530, the application module determines that the first party is not to be restricted based on the subscriber feature code received during step 510, the output of the unrestricted party accumulator is transmitted to the first telephone terminal (step 545) and the output of the restricted party accumulator is transmitted to the second telephone terminal (step 550).

The foregoing represents a mechanism whereby a monitoring party is able to communicated with one of the monitored parties but not be heard by another party. The mechanism is particularly useful in the law enforcement context where law enforcement personnel can monitor a conversation between an informant and an investigated party, and communicate instructions to the informant without being heard by the investigated party.

Although the invention has been described with a certain degree of particularity, it should be recognized that elements thereof may be altered by persons skilled in the art without departing from the spirit and scope of the invention.

Therefore, the invention is limited only by the following claims and their equivalents.

Claims

WHAT IS CLAIMED IS:

1. An apparatus for connecting a multiparty call, said apparatus comprising: an unrestricted party accumulator receiving signals from a first unrestricted party, a second unrestricted party, and a restricted party; and a restricted party accumulator simultaneously receiving signals from said first unrestricted party and said restricted party; wherein an output of said unrestricted party accumulator is transmitted signals to said first unrestricted party and said second unrestricted party, but not to said restricted party; and wherein an output of said restricted party accumulator is simultaneously transmitted signals to said restricted party.

2. The apparatus of claim 1, wherein said restricted party accumulator does not receive signals from said second unrestricted party.

3. A method for establishing a telephone call between a first party, a second party, and a third party, said method comprising the steps of: accumulating signals received from said first party, said second party, and said third party to generate a first accumulated signal; transmitting said first accumulated signal to said first party and said second party, but not said third party; simultaneously accumulating signals received from said second party, but not said first party, to generate a second accumulated signal; simultaneously transmitting said second accumulated signal to said third party.

4. A telecommunications switch for establishing a call between a plurality of parties, said telecommunications switch comprising: a group switch/time switch for receiving signals from said plurality of parties; an application module for determining a restricted group of parties, said restricted group of parties forming a portion of said plurality of parties, and for determining an unrestricted group of parties, said unrestricted group of parties forming a portion of said plurality of parties; a call conferencing device comprising: a restricted party accumulator for accumulating signals received from said restricted group of parties; and an unrestricted party accumulator for accumulating signals received from each party and transmitting said accumulated signal from each party to said unrestricted group of parties, but not transmitting said accumulated signal from each party to said restricted group of parties; and a controller for causing said group switch/time switch to input said signals from said plurality of parties to said call conferencing device during said multiparty call.

5. The telecommunications switch of claim 4, wherein said application module determines said restricted group of parties and said unrestricted group of parties by receiving a subscriber feature code.

6. A method for establishing a telephone call between a first party, a second party, and a third party, said method comprising the steps of: accumulating signals received from said first party, said second party, and said third party to generate a first accumulated signal; determining whether said first party is authorized to receive communications from said third party; and wherein said first party is authorized to receive communications from said third party: simultaneously accumulating signals received from said second party and said third party to generate a second accumulated signal; transmitting said first accumulated signal to said first party and said second party, but not said third party; and simultaneously transmitting said second accumulated signal to said third party; and wherein said first party is not authorized to receive communications from said third party: simultaneously accumulating signals received from said first party and said second party to generate a second accumulated signal; transmitting said first accumulated signal to said second party and said third party, but not said first party; and simultaneously transmitting said second accumulated signal to said first party.

7. The method of claim 6, further comprising the steps of: establishing a call between said first party and said second party; receiving a hook-flash from said second party; establishing a call between said second party and said third party; and receiving a hook-flash back from said second party.

8. The method of claim 6, wherein said determining step further comprises receiving a subscriber feature code from said second party, said subscriber feature code indicating whether said first party is supposed to receive communications from said third party.

9. During a telephone call between a first party, a second party, and a third party, a method for said first party to selectively restrict said second party or said third party, said method comprising the steps of: receiving a hook flash from said third party; accumulating signals received from said first party, said second party, and said third party to generate a first accumulated signal, responsive to said receiving step; and accumulating signals received from said first party and said second party to generate a second accumulated signal, responsive to said receiving step.

10. The method of claim 9, further comprising the steps of: receiving a particular subscriber code, said subscriber code indicating whether said first party or said second party is to be restricted; and wherein said particular subscriber code indicates that said first party is to be restricted: transmitting said first accumulated signal to said second party and said third party; and transmitting said second accumulated signal to said first party; and wherein said particular subscriber code indicates that said second party is to be restricted: transmitting said first accumulated signal to said first party and said third party; and transmitting said second accumulated signal to said second party.