Patent Publication Number: US-2007121876-A1

Title: System for managing the transfer of a call waiting party into an existing subscriber call connection to replace a terminal device on the existing call connection

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
      This application is related to a U.S. patent application titled “System For Managing The Addition Of A Call Waiting Party To An Existing Subscriber Call Connection” and filed on the same date as the present application. 
    
    
     FIELD OF THE INVENTION  
      This invention relates to communication networks and the management of existing call connections with respect to call waiting call parties.  
     BACKGROUND OF THE INVENTION  
      It is a problem in the field of communication networks to enable a subscriber, who is a call waiting party on an existing call connection, to replace one of the two parties on the existing call connection.  
      Presently, when a party who is on an existing call connection has a third party in a call waiting mode, there is no ability to enable one of the two parties on the existing call connection to drop off the call and replace this party with the call waiting party. The addition of another (third) party into an existing call connection can only occur in the present telephone network in the form of one of the two parties on the existing call connection initiating Three Way Calling and calling the third party. The Three Way Calling feature adds the third party to the existing call connection but cannot respond to a third party calling in to one of the two parties on an existing call connection. Therefore, the existing communication network is unable, in an existing call connection with a call waiting party, to enable one of the two parties on the existing call connection to drop off the call and replace this party with the call waiting party.  
     BRIEF SUMMARY OF THE INVENTION  
      The above-described problems are solved and a technical advance achieved by the present System For Managing The Transfer Of A Call Waiting Party Into An Existing Subscriber Call Connection To Replace A Terminal Device On The Existing Call Connection, herein termed “system for transferring a call connection to a call waiting party”. This system enables a party on the existing call connection who receives an incoming call from a third party to drop off the existing call connection and be replaced with the third party without disrupting the existing call connection.  
      The system for transferring a call connection to a call waiting party operates when an incoming call is directed to one of the parties on the existing call connection. The called party receives an indication of the incoming call and flashes the switch-hook on their terminal device to place the other party on the existing call connection on hold and also to pick up the incoming call. After speaking with the calling party, the called party determines that the calling party should communicate with only the other party on the existing call connection, who is presently on hold. The called party can place the calling party (also termed “call waiting party”) on hold to confer with the other party on the existing call connection before adding the call waiting party into the existing call connection.  
      The process of transferring a call connection to a call waiting party can be realized in two different ways. The called party can operate their terminal device by inputting specific digits or a code to activate the system for transferring a call connection to a call waiting party which responds by maintaining the existing call connection while adding the calling party to the existing call connection and disconnecting the called party from the existing call connection. Two parties are then on the call connection—the calling party and the other party on the existing call connection—and these two parties continue to converse until one of the two parties disconnects from the call, creating the billing record and releasing the call resources. Alternatively, the called party can dial a predetermined code to connect the call waiting party into a three way call and then subsequently enter a predetermined code to drop the called party from the call connection, allowing the other party from the original call connection and the call waiting party to continue on the call. In both cases the party dropping out can make and receive calls without interference from the call connection from which they disconnected. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  illustrates, in block diagram form, the overall architecture of a telephone network and a typical call connection that uses the present system for transferring a call connection to a call waiting party, and  
       FIG. 2  illustrates, in flow diagram form, the operational steps taken by the present system for transferring a call connection to a call waiting party to implement a call transfer for a terminal device. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
       FIG. 1  illustrates, in block diagram form, the overall architecture of a telephone network and a typical call connection that uses the present system for transferring a call connection to a call waiting party; and  FIG. 2  illustrates, in flow diagram form, the operational steps taken by the present system for transferring a call connection to a call waiting party to implement a call transfer for a terminal device.  
      The communications network comprises a traditional voice communications network that includes a plurality of local communications systems  101 , 102 , which could be a PSTN land configuration, wireless configuration or a combination of the two, such as telephone switching systems that are part of the Public Switched Telephone Network (PSTN)  100  and are interconnected via trunk circuits (or an IP connection) to an Inter-Exchange Carrier System (IXC)  103 . Each of the communications systems  101 ,  102  serve a plurality of terminal devices  111 - 113 ,  121 - 123 , respectively, and the communications systems  101 ,  102  may be interconnected via an out-of-band signaling link CS through the Inter-Exchange Carrier System (IXC)  103 , using the well-known SS7 signaling protocol or the IP protocol. The operation of such a communications network is well known and is not described in detail herein. The communications systems  101 ,  102  provide a set of features and services to the terminal devices that they serve, including a system for transferring a call connection to a call waiting party wherein the communications systems  101 ,  102  implement the call transfer function for the associated terminal devices in response to control signals that are received from the terminal devices. In addition, the communications systems  101 ,  102  are both equipped with the system for transferring a call connection to a call waiting party CHN 1 , CHN 2 , that are operational in the controllers  101 C,  102 C of the respective communications systems  101 ,  102 .  
      For the purpose of illustration, the call connection used to describe the operation of the present system for transferring a call connection to a call waiting party CHN 2  consists of terminal device  111  connected to terminal device  122 . The connection extends from terminal device  111  through communication system  101  (path  1 ), Inter-Exchange Carrier System (IXC)  103  (path  2 ), communication system  102  (path  3 ), to terminal device  122 . The use of multiple communication systems and the Inter-Exchange Carrier System (ICX) for the call connection is not a limitation on the operation of the system for transferring a call connection to a call waiting party CHN 2 , since the call connection can be solely within communication system  102 , or may include one or more mobile terminal devices and their associated Mobile Switching Centers (not shown).  
      In this environment, the only way to add a third party to the existing call connection or to substitute a third party for one of the two parties on the existing call connection is to use the Three Way Calling feature. The Three Way Calling feature is initiated when one of the two parties (first party) on the existing call connection flashes the switch-hook to place the other party on hold and initiates a call to the third party. The third party is then connected to the first party, who can again flash the switch-hook to add the third party to the existing call connection. Unfortunately, this feature is only outbound capable, in that one of the two parties on the existing call connection is the only one who can contact the third party.  
      The system for transferring a call connection to a call waiting party operates to enable a third party (calling party to contact one party on an existing call connection and be substituted for that party on the existing call connection. This process is initiated when, at step  201 , an incoming call from calling party located at terminal device  121  is directed to the terminal device  122  of one of the parties (called party) on the existing call connection (paths  1 - 3 ). The called party receives an indication of the incoming call on their terminal device  122  at step  202  and flashes the switch-hook of their terminal device  122  (or generates some other control signal) at step  203  to place the terminal device  111  of the other party on the existing call connection on hold and to also pick up the incoming call from the calling party by connecting the terminal device  121  of the calling party to the terminal device  122  of the called party over path  4 . After speaking with the calling party, the called party at step  204  determines that the calling party should communicate with only the other party on the existing call connection, who is presently on hold. The called party then operates their terminal device  122  at step  205  to place the calling party (also termed “call waiting party”) on hold to confer with the other party on the existing call connection before adding the call waiting party into the existing call connection.  
      The process of transferring a call connection to a call waiting party can be realized in two different ways. The called party can dial a predetermined code to connect the call waiting party into a three way call and then subsequently enter a predetermined code to drop the called party from the call connection, allowing the other party from the original call connection and the call waiting party to continue on the call. Alternatively, the called party can dial a predetermined code to connect the call waiting party into the call connection and to drop the called party from the call connection, allowing the other party from the original call connection and the call waiting party to continue on the call. Since the second case is a subset of the first case, the three way connection is described herein, with the realization that the process can be implemented by simply jumping to step  207 .  
      The called party then operates their terminal device  122  at step  206  by inputting specific digits or a code to activate the system for transferring a call connection to a call waiting party CHN 2 , which responds by maintaining paths  1 - 2  of the existing call connection while adding the terminal device  121  of the calling party to the existing call connection via path  5  at step  207 . The three parties are then all connected and can converse until the called party at step  208  operates their terminal device  122  to input specific digits or a code to activate the system for transferring a call connection to a call waiting party CHN 2 , which responds by disconnecting the terminal device  122  of the called party from the existing call connection at step  209 .  
      Two parties are then on the call connection (paths  1 ,  2 ,  5 )—the calling party at terminal device  121  and the other party on the existing call connection at terminal device  111 —and these two parties continue to converse until one of the two parties disconnects from the call at step  210 , creating the billing record and releasing the call resources at step  211 . Alternatively, one of these two parties can receive an incoming call and the above-described process can be repeated, where the calling party is added to the existing call connection or a three way call can be created.  
      This service is beneficial in the case of a service dispatcher (called party), where a service personnel calls in to the dispatcher and a third party customer (calling part) is added to the call, and the service personnel and customer converse without the need for the dispatcher being involved.  
     SUMMARY  
      The system for transferring a call connection to a call waiting party enables a party on the existing call connection who receives an incoming call from a third party to drop off the existing call connection and be replaced with the call waiting party without disrupting the existing call connection.