Abstract:
A telecommunications system is disclosed that enables a user to pair a desk set that is an extension of a private-branch exchange with a cell phone that is accessible via the Public Switched Telephone Network. One feature of the telecommunications system enables an active call that is between the desk set and another party, to be transferred to the user&#39;s cell phone, while in the presence of third-party call control. This is advantageous because a user who is initially on a call at her desk set, but needs to get somewhere else (e.g., a meeting, the airport, home, etc.), is able to continue the call by transferring it to her cell phone. The third-party call control can be part of a computer-telephony integration (CTI) application—for example, in a telephone telemarketing center, which concurrently handles many active telephone calls.

Description:
FIELD OF THE INVENTION 
     The present invention relates to telecommunications in general, and, more particularly, to computer-telephony integration. 
     BACKGROUND OF THE INVENTION 
     A business that desires to provide employees at one location with telephones has, in general, two options. First, the business can acquire one telephone and one telephone line per employee from the telephone company. Second, the business can acquire one telephone per employee, a small number of telephone lines from the telephone company, and a piece of equipment that enables the employee&#39;s telephones to share the small number of telephone lines. In general, the second option is substantially less expensive than the first option, and the piece of equipment that enables the employees&#39; telephones to share the small number of telephone lines is called a “private-branch exchange” or “PBX.” Private-branch exchanges are also capable of providing valuable telecommunications features to their users. 
     SUMMARY OF THE INVENTION 
     The present invention enables a valuable capability of a telecommunications system. In the prior art, one feature of a telecommunications system enables a user to pair a desk set that is an extension of a private-branch exchange with a cell phone that is accessible via the Public Switched Telephone Network. The feature enables an active call that is between the desk set and another party, to be transferred to the user&#39;s cell phone. This is advantageous because a user who is initially on a call at her desk set, but needs to get to somewhere else (e.g., a meeting, the airport, home, etc.) before the call is over, is able to continue the call by transferring it to her cell phone. 
     The illustrative embodiment of the present invention also provides the transfer feature, but does so when a third party serves as a front-end to the cell phone and, as such, acts as an agent to the cell phone in controlling calls to and from the cell phone. Such a third party includes a computer-telephony integration (CTI) application in a telephone telemarketing center, which concurrently handles many active telephone calls. Third-party CTI applications are often not inherently integrated with some or all of the features provided by the co-existing private-branch exchanges. The illustrative embodiment enables such CTI applications to interwork with legacy private branch exchanges or other equipment. 
     The illustrative embodiment comprises receiving a request to bridge an active call that exists between a telephone number D and a telephone number T, to a telephone number C; allocating, from a pool of ports, a port P that is capable of emulating a telephone extension; and establishing a resultant call between the telephone number T and the telephone number C, the resultant call being based on the active call and on at least one precursor call having been made that includes port P; wherein the telephone number C is associated with the telephone number D in a data structure and is within the address space of the Public Switched Telephone Network; and wherein the telephone number D is within the address space of a private-branch exchange. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  depicts a schematic diagram of the salient components of telecommunications system  100  in accordance with the illustrative embodiment of the present invention. 
         FIG. 2  depicts a flowchart of the salient task performed by the illustrative embodiment of the present invention. 
         FIG. 3  depicts a flowchart of the salient tasks of task  201  in accordance with the illustrative embodiment of the present invention. 
         FIGS. 4   a ,  4   b ,  4   c , and  4   d  depict graphs of the salient components of the precursor calls and resultant calls. 
         FIG. 5  depicts a flowchart of the salient task performed by the illustrative embodiment in accomplishing task  301 . 
         FIG. 6  depicts a flowchart of the salient tasks performed by the illustrative embodiment in accomplishing task  302 . 
         FIG. 7  depicts a flowchart of the salient task performed by the illustrative embodiment in accomplishing task  303 . 
         FIG. 8  depicts a flowchart of the salient task performed by the illustrative embodiment in accomplishing task  304 . 
         FIG. 9  depicts a flowchart of the salient task performed by the illustrative embodiment in accomplishing task  305 . 
         FIG. 10  depicts a flowchart of the salient task performed by the illustrative embodiment in accomplishing task  307 . 
     
    
    
     DETAILED DESCRIPTION 
     Telecommunications System  100 — 
       FIG. 1  depicts a schematic diagram of the salient components of telecommunications system  100  in accordance with the illustrative embodiment of the present invention. Telecommunications system  100  comprises affiliated PSTN terminal  101 , unaffiliated PSTN terminal  102 , private-branch exchange (PBX) terminal  103 , private-branch exchange (PBX) telephone system  104 , Public Switched Telephone Network  105 , and computer-telephony integration (CTI) application  106  interconnected as shown. 
     Although the illustrative embodiment comprises one affiliated PSTN telecommunications terminal, one unaffiliated PSTN telecommunications terminal, and one PBX telecommunications terminal, it will be clear to those skilled in the art, after reading this disclosure, how to make and use alternative embodiments of the present invention that comprise any number of affiliated PSTN telecommunications terminals, unaffiliated PSTN telecommunications terminals, and PBX telecommunications terminals. 
     Affiliated PSTN terminal  101  is a telecommunications terminal that corresponds to telephone number C in address space  111  of Public Switched Telephone Network  105 . Terminal  101  is off-premises in relation to the on-premises enterprise region served by PBX telephone system  104 . It will be clear to those skilled in the art, after reading this specification, how to make and use alternative embodiments of the present invention in which affiliated PSTN terminal  101  corresponds to a telephone number in the address space of a private branch exchange, such as, for example and without limitation, address space  112  of private branch exchange  104 . In accordance with the illustrative embodiment, affiliated PSTN terminal  101  is a wireless terminal (e.g., cellular telephone, etc.). It will be clear to those skilled in the art, after reading this disclosure, how to make and use alternative embodiments of the present invention in which affiliated PSTN terminal  101  is a wireline terminal. It will be clear to those skilled in the art how make and use affiliated PSTN terminal  101 . 
     Unaffiliated PSTN terminal  102  is a telecommunications terminal that corresponds to telephone number T in address space  111  of Public Switched Telephone Network  105 . It will be clear to those skilled in the art, after reading this disclosure, how to make and use alternative embodiments of the present invention in which unaffiliated PSTN terminal  102  corresponds to a telephone number in the address space of a private branch exchange, such as, for example and without limitation, address space  112  of private branch exchange  104 . In accordance with the illustrative embodiment, unaffiliated PSTN terminal  102  is a wireless terminal (e.g., cellular telephone, etc.). It will be clear to those skilled in the art, after reading this disclosure, how to make and use alternative embodiments of the present invention in which unaffiliated PSTN terminal  102  is a wireline terminal. It will be clear to those skilled in the art how to make and use unaffiliated PSTN terminal  102 . 
     PBX terminal  103  is a telecommunications terminal that corresponds to telephone number D in address space  112  of private branch exchange  104 . It will be clear to those skilled in the art, after reading this disclosure, how to make and use alternative embodiments of the present invention in which PBX terminal  103  corresponds to a telephone number in address space  111  of the Public Switched Telephone Network or the address space of another private branch exchange. In accordance with the illustrative embodiment, terminal  103  is a wireline terminal. It will be clear to those skilled in the art, after reading this disclosure, how to make and use alternative embodiments of the present invention in which terminal  103  is a wireless terminal. It will be clear to those skilled in the art how to make and use terminal  103 . 
     Private-branch exchange  104  is a switch that provides telecommunications service to PBX terminal  103 . Private branch exchange  104  comprises a data structure that associates the telephone number that corresponds to the PBX terminal  103  with the telephone number that corresponds to affiliated terminal  101 . An example of such a data structure is depicted in Table 1. 
                                   TABLE 1                   Data Structure That Associates the Telephone Number That Corresponds       to PBX Terminal 103 with the Telephone Number That Corresponds       to Affiliated Terminal 101                Telephone Number   Telephone Number           That Corresponds   That Corresponds to           to PBX Terminal 103   Affiliated Terminal 101                       D   C                        
Although the illustrative embodiment associates one pair of telephone numbers, it will be clear to those skilled in the art, after reading this disclosure, how to make and use alternative embodiments of the present invention that associate any number of pairs.
 
     Private-branch exchange  104  further comprises call-resource pool  107 , which in turn comprises a plurality of CTI ports. It will be clear to those skilled in the art, after reading this disclosure, how to make and use embodiments of the present invention that comprise any number of CTI ports. Each port P is a logical point of connection that is capable of emulating a telephone extension, at least in the sense that within private-branch exchange  104 , a call can be placed to a port, placed from a port, put on hold at a port, or transferred to or from a port. The particular telephone extension that a given port emulates might be known only to CTI application  106  and to private-branch exchange  104  itself, but not necessarily to any other device in system  100 . At least one of CTI application  106  and private-branch exchange  104  is able to monitor the busy/idle status of each port P. 
     As those who are skilled in the art will appreciate, provisioning a greater number of ports will tend to result in a lower blocking level in the handling of calls, but can require additional resources with an associated additional cost. It will be clear to those skilled in the art how to determine an optimal provisioning of ports, for a given blocking level versus cost tradeoff. Additionally, it will be clear to those skilled in the art how to provision and administer the ports of pool  107 . 
     In accordance with the illustrative embodiment, the operation of private-branch exchange  104  and PBX terminal  103  can be directed by computer-telephony integration application  106  in well-known fashion. The details of how to make and use private-branch exchange  104  are described in detail below and in the following drawings. 
     Public Switched Telephone Network  105  is the public telephone network. It will be clear to those skilled in the art how to make and use Public Switched Telephone Network  105 . 
     Computer-telephony integration (CTI) application  106  is a combination of hardware and software that directs the operation of private-branch exchange  104  and PBX terminal  103 . In particular, the CTI application provides the functionality described in detail below and in the accompanying figures. It will be clear to those skilled in the art, after reading this disclosure, how to make and use alternative embodiments of the present invention, in which CTI application  106  is absent and its functionality is performed by private-branch exchange  104  or by a natural person or by a combination of private-branch exchange  104  and by a natural person. 
     In accordance with the illustrative embodiment, CTI application  106  runs on an independent, general-purpose processor. It will be clear to those skilled in the art, after reading this disclosure, how to make and use alternative embodiments of the present invention in which CTI application  106  runs on an adjunct processor of private-branch exchange  104 , a component of one or more of the terminals of telecommunication system  100 , or on a special-purpose processor. The details of how to make and use CTI application  106  are described in detail below and in the following drawings. 
     Operation of the Illustrative Embodiment— 
       FIG. 2  depicts a flowchart of the salient task performed by the illustrative embodiment of the present invention. 
     Task  201  comprises extending an active call that is between telephone number T to telephone number D, to telephone number C. The details of how to perform task  201  are described in detail below and with respect to the following drawings. 
     Establish Resultant Call— 
       FIG. 3  depicts a flowchart of the salient tasks of task  201  in accordance with the illustrative embodiment of the present invention. 
     At task  301 , CTI application  106  receives notification that an active call exists that includes telephone number D (i.e., that has D as a party to the call).  FIG. 4   a  depicts a graph of the salient components of active call  421 ; in this example, active call  421  was placed from telephone number T to telephone number D and, as a result, comprises connections  401 - 1  and  401 - 2 . After receiving the notification of the active call, application  106  notifies affiliated PSTN terminal  101  of the call. It will be clear to those skilled in the art how to make and use embodiments of the present invention that accomplish task  301 . 
     At task  302 , CTI application  106  receives a request from terminal  101 , the affiliated PSTN terminal, to bridge the active call to telephone number C, a telephone number of terminal  101 . For the purposes of this specification and the appended claims, the term “bridge” can mean either to join telephone number C to the call without dropping any of the parties already on the call or to transfer or switch the call to telephone number C, in the process dropping telephone number D from the call. As a result of receiving the request, application  106  directs private-branch exchange  104  to establish a first precursor call to telephone number D from a CTI port, and to enable the extending of the call to the telephone number of the affiliated PSTN terminal (i.e., telephone number C). The details of task  302  are described in detail below and in the accompanying figures. 
     In response to task  302 , private-branch exchange  104  establishes at task  303  the first precursor call that includes telephone number D and telephone number C.  FIG. 4   b  depicts a graph of the salient components of active call  421  and first precursor call  422 , which comprises connections  402 - 1  and  402 - 2 . The details of task  303  are described in detail below and in the accompanying figures. 
     At task  304 , CTI application  106  directs private-branch exchange  104  to establish a second precursor call from telephone number D to port P. In accordance with the illustrative embodiment, task  304  is distinct from task  302 . It will be clear to those skilled in the art, however, after reading this disclosure, how to make and use alternative embodiments of the present invention in which tasks  302  and  304  are combined or concurrent or performed in the opposite order. It will be clear to those skilled in the art how to make and use embodiments of the present invention that accomplish task  304 . 
     In response to task  304 , private-branch exchange  104  establishes at task  305 , the second precursor call from telephone number D to port P.  FIG. 4   c  depicts a graph of the salient components of active call  421 , first precursor call  422 , and second precursor call  423 , which comprises connection  403 - 1 . In accordance with the illustrative embodiment, task  303  is performed before task  305 . It will be clear to those skilled in the art, after reading this specification, how to make and use alternative embodiments of the present invention in which task  303  and task  305  are performed concurrently or in the opposite order. It will be clear to those skilled in the art how to make and use embodiments of the present invention that accomplish task  305 . 
     At task  306 , CTI application  106  directs private-branch exchange  104  to combine all three calls (i.e., one active and two precursor) to generate a resultant call between telephone number T and telephone number C while bridging telephone number D to the call. In accordance with the illustrative embodiment, task  306  is distinct from task  302  and task  304 . It will be clear to those skilled in the art, after reading this disclosure, how to make and use alternative embodiments of the present invention in which task  302 , task  304 , and task  306  are combined or concurrent or performed in any order. It will be clear to those skilled in the art how to make and use embodiments of the present invention that accomplish task  306 . 
     In response to task  306 , private-branch exchange  104  combines, at task  307 , all three calls to generate the resultant call between telephone number T and telephone number C while bridging telephone number D to the call. In accordance with the illustrative embodiment, the combination of the three precursor calls results in two-party resultant call  424  comprising connections  401 - 1 ,  401 - 2 , and  402 - 2 , as depicted in  FIG. 4   d . Task  307  is described in detail below and in the accompanying figures. 
     Notification of Active Call— 
       FIG. 5  depicts a flowchart of the salient tasks performed by the illustrative embodiment in accomplishing task  301 . 
     At task  501 , CTI application  106  receives notification of an active call between telephone numbers T and D. 
     At task  502 , CTI application  106 , in response to having received the active-call notification, notifies the corresponding affiliated PSTN terminal (i.e., terminal  101 ) about the call. 
     Direct the Establishment of First Precursor Call— 
       FIG. 6  depicts a flowchart of the salient tasks performed by the illustrative embodiment in accomplishing task  302 . 
     At task  601 , CTI application  106  receives a request from the affiliated telecommunications terminal to be bridged to the active call. As those who are skilled in the art will appreciate, the terminal can transmit the request to application  106  either spontaneously or as the result of having received notification of the active call in conjunction with task  502 . 
     At task  602 , CTI application  106  determines that a port from pool  107 , namely port P, is available to set up one or more precursor calls. Application  106  directs private-branch exchange  104  to: (i) enable a call made to telephone number D to be extended to the telephone number of the affiliated PSTN terminal (i.e., telephone number C); (ii) establish the first precursor call from selected port P to telephone number D; and (iii) place the first precursor call on hold. It will be clear to those skilled in the art how to make and use embodiments of the present invention that accomplish task  302 . 
     In some embodiments, directing exchange  104  comprises transmitting one or more messages that: (i) direct the enabling of the extending of calls that are placed to telephone number D, to a telephone number of an affiliated terminal; (ii) direct the placing of the first precursor call; or (iii) direct the placing of the first precursor call on hold, or direct in some combination thereof. 
     Establish First Precursor Call— 
       FIG. 7  depicts a flowchart of the salient tasks performed by the illustrative embodiment in accomplishing task  303 . 
     At task  701 , private-branch exchange  104  is directed by CTI application  106 , via one or more received messages, to establish a first precursor call from selected port P to telephone number D and to place the first precursor call on hold. In accordance with the illustrative embodiment, CTI application  106  directs private-branch exchange  104  to establish the first precursor call. 
     In some embodiments, the messages that exchange  104  receives comprise one or more messages that: (i) direct the enabling of the extending of calls that are placed to telephone number D, to a telephone number of an affiliated terminal; (ii) direct the placing of the first precursor call; or (iii) direct the placing of the first precursor call on hold, or direct in some combination thereof. 
     At task  702 , private-branch exchange  104  allocates port P to be used for originating the call to telephone number D. 
     At task  703 , private-branch exchange  104  enables the extending to telephone number C of one or more calls made to telephone number D. Exchange  104  then establishes the first precursor call from port P to telephone number D, in well-known fashion. 
     At task  704 , in response to the call to telephone number D and to having enables the call extension capability, private-branch exchange  104  extends the first precursor call to telephone number C, in well-known fashion. 
     At task  705 , private-branch exchange  104  places the first precursor call on hold, in well-known fashion. 
     Direct the Establishment of Second Precursor Call— 
       FIG. 8  depicts a flowchart of the salient tasks performed by the illustrative embodiment in accomplishing task  304 . 
     At task  801 , CTI application  106  directs private-branch exchange  104  to establish a second precursor call from telephone number D to port P. It will be clear to those skilled in the art how to make and use embodiments of the present invention that accomplish task  304 . 
     In some embodiments, directing exchange  104  comprises transmitting one or more messages that: (i) direct the placing of the active call on hold; (ii) direct the placing of the second precursor call; (iii) direct the answering of the second precursor call; or (iv) direct the placing of the second precursor call on hold, or direct in some combination thereof. 
     Establish Second Precursor Call— 
       FIG. 9  depicts a flowchart of the salient tasks performed by the illustrative embodiment in accomplishing task  305 . 
     At task  901 , private-branch exchange  104  is directed by CTI application  106  to establish a second precursor call from telephone number D to port P, in accordance with the illustrative embodiment. 
     In some embodiments, the messages that exchange  104  receives comprise one or more messages that: (i) direct the placing of the active call on hold; (ii) direct the placing of the second precursor call; (iii) direct the answering of the second precursor call; or (iv) direct the placing of the second precursor call on hold, or direct in some combination thereof. 
     At task  902 , exchange  104  places the active call on hold. 
     At task  903 , private-branch exchange  104  establishes the second precursor call from telephone number D to port P, in well-known fashion. 
     In some embodiments, exchange  104  then answers the second precursor call and places the precursor call on hold. 
     Combining the Calls— 
       FIG. 10  depicts a flowchart of the salient task performed by the illustrative embodiment in accomplishing task  307 . 
     At task  1001 , private-branch exchange  104  retrieves the active call (i.e., the call between telephone number T and telephone number D), in well-known fashion. 
     At task  1002 , private-branch exchange  104  merges the second precursor call (i.e., from telephone number D to port P) with the active call at telephone number D, in well-known fashion. 
     At task  1003 , private-branch exchange  104  merges the first precursor call (i.e., from port P to telephone number D, extended to telephone number C) with the already-merged active call (i.e., between telephone number T and port P), in well-known fashion; the effect of this is to create the resultant call. Exchange  104  then drops port P as a result of the merging. 
     At task  1004 , private-branch exchange  104  deallocates port P, thereby enabling the port to be reused to support future calls that are controlled via CTI application  106 . 
     It is to be understood that the above-described embodiments are merely illustrative of the present invention and that many variations of the above-described embodiments can be devised by those skilled in the art without departing from the scope of the invention. For example, in this Specification, numerous specific details are provided in order to provide a thorough description and understanding of the illustrative embodiments of the present invention. Those skilled in the art will recognize, however, that the invention can be practiced without one or more of those details, or with other methods, materials, components, etc.