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 incoming call that is directed to the user&#39;s desk set to be automatically forwarded to the user&#39;s cell phone, while in the presence of third-party call control. This is advantageous to the user because it provides the illusion to the caller that the user is physically in his or her office when she is not necessarily there. The third-party call control can be part of a computer-telephony integration (CTI) application—for example, in a telephone telemarketing center, which handles many incoming 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 a call that is directed to the user&#39;s desk set to be automatically forwarded to the user&#39;s cell phone. This is advantageous to the user because it provides the illusion to the caller that the user is physically in her office when she is not necessarily there. 
     The illustrative embodiment of the present invention also provides the illusion, but does so when a third party initiates a call setup that connects the calling party to the user&#39;s cell phone, as the result of an incoming call that is initially directed to the user&#39;s desk set. Such a third party includes a computer-telephony integration (CTI) application in a telephone telemarketing center, which handles many incoming telephone calls. In some techniques in the prior art, when a third party was involved with an incoming call from a calling party to a user&#39;s desk set, the incoming call would be connected to the desk set only. This would inconvenience the calling party when the user was not at her desk set, in that the call would go unanswered. In some other techniques in the prior art, the incoming call would be forwarded to the cell phone, which would result in the desk set being excluded from the call. This would inconvenience the user (i.e., the called party), in that the user might actually want the call sent to the desk set, instead of or in addition to the cell phone. 
     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 first precursor call from a telephone number T to a telephone number D; 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 a telephone number C; wherein the telephone number C is associated with the telephone number D in a data structure; wherein the telephone number D is within the address space of a private-branch exchange; and wherein the resultant call is based on at least one precursor call having been made that includes port P. 
    
    
     
       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  303 . 
         FIG. 7  depicts a flowchart of the salient task performed by the illustrative embodiment in accomplishing task  304 . 
         FIG. 8  depicts a flowchart of the salient task performed by the illustrative embodiment in accomplishing task  305 . 
         FIG. 9  depicts a flowchart of the salient task performed by the illustrative embodiment in accomplishing task  306 . 
         FIG. 10  depicts a flowchart of the salient task performed by the illustrative embodiment in accomplishing task  308 . 
     
    
    
     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 establishing a resultant call from telephone number T to telephone number D while extending the call to telephone number C. The details of how to perform task  201  are described in detail below and with respect to the following drawings. 
     In some alternative embodiments, an active call that is either incoming or outgoing is established initially between telephone number T and telephone number D, and then sometime later, telephone number C is bridged (e.g., joined, etc.) onto the active call. In those alternative embodiments, the affiliated telecommunications terminal that corresponds to telephone number C can initiate the bridging or the bridging can initiated by other means (e.g., automatically by private-branch exchange  104 , etc.). It will be clear to those skilled in the art, after reading this specification, how to apply the techniques of the illustrative embodiment to bridge or transfer, to telephone number C, an already-established, active call that includes telephone numbers T and D (i.e., that has T and D as parties to the call). 
     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 , private-branch exchange  104  to receives an incoming, first precursor call from telephone number T to telephone number D and notifies CTI application  106  of the incoming call.  FIG. 4   a  depicts a graph of the salient components of first precursor call  421 , which comprises connection  401 - 1  and connection  401 - 2 . 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  notifies affiliated PSTN terminal  101  of the incoming call. If terminal  101  accepts the call, the terminal sends back an indication of the call acceptance to CTI application  106 . It will be clear to those skilled in the art how to make and use embodiments of the present invention that accomplish task  302 . 
     At task  303 , CTI application  106  receives the indication of the call acceptance from terminal  101  and, as a result, directs private-branch exchange  104  to establish a second 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  303  are described in detail below and in the accompanying figures. 
     In response to task  303 , private-branch exchange  104  establishes at task  304  the second precursor call that includes telephone number D and telephone number C.  FIG. 4   b  depicts a graph of the salient components of first precursor call  421  and second precursor call  422 , which comprises connection  402 - 1  and connection  402 - 2  from port P. The details of task  304  are described in detail below and in the accompanying figures. 
     At task  305 , CTI application  106  directs private-branch exchange  104  to establish a third precursor call from telephone number D to port P. In accordance with the illustrative embodiment, task  305  is distinct from task  303 . 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  303  and  305  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  305 . 
     In response to task  305 , private-branch exchange  104  establishes at task  306 , the third precursor call from telephone number D to port P.  FIG. 4   c  depicts a graph of the salient components of first precursor call  421 , second precursor call  422 , and third precursor call  423 , which comprises connection  403 - 1 . In accordance with the illustrative embodiment, task  304  is performed before task  306 . 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  304  and task  306  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  306 . 
     At task  307 , CTI application  106  directs private-branch exchange  104  to combine all three precursor calls 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  307  is distinct from task  303  and task  305 . 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  303 , task  305 , and task  307  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  307 . 
     In response to task  307 , private-branch exchange  104  combines, at task  308 , all three precursor 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  306  is described in detail below and in the accompanying figures. 
     Arrival of First Precursor Call— FIG. 5  depicts a flowchart of the salient tasks performed by the illustrative embodiment in accomplishing task  301 . 
     At task  501 , private branch exchange  104  receives an incoming call from telephone number T and intended for the user of telephone number D. The incoming call is also referred to as the first precursor call. 
     At task  502 , private branch exchange  104 , in response to having received the incoming call, notifies CTI application  106  about the call. 
     Direct the Establishment of Second Precursor Call— FIG. 6  depicts a flowchart of the salient tasks performed by the illustrative embodiment in accomplishing task  303 . 
     At task  601 , CTI application  106  receives an indication of call acceptance from the telecommunications terminal (e.g., terminal  101 , etc.) of the user to which the incoming call is intended. 
     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 second precursor call from selected port P to telephone number D; and (iii) place the second 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  303 . 
     Establish Second Precursor Call— FIG. 7  depicts a flowchart of the salient tasks performed by the illustrative embodiment in accomplishing task  304 . 
     At task  701 , private-branch exchange  104  is directed by CTI application  106  to establish a second precursor call from selected port P to telephone number D and to place the second precursor call on hold. In accordance with the illustrative embodiment, CTI application  106  directs private-branch exchange  104  to establish the second precursor call. 
     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  establishes the second 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, private-branch exchange  104  extends the second precursor call to telephone number C, in well-known fashion. 
     At task  705 , private-branch exchange  104  places the second precursor call on hold, in well-known fashion. 
     Direct the Establishment of Third Precursor Call— FIG. 8  depicts a flowchart of the salient tasks performed by the illustrative embodiment in accomplishing task  305 . 
     At task  801 , CTI application  106  directs private-branch exchange  104  to establish a third 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  305 . 
     Establish Third Precursor Call— FIG. 9  depicts a flowchart of the salient tasks performed by the illustrative embodiment in accomplishing task  306 . 
     At task  901 , private-branch exchange  104  is directed by CTI application  106  to establish a third precursor call from telephone number D to port P, in accordance with the illustrative embodiment. 
     At task  902 , private-branch exchange  104  establishes the third precursor call from telephone number D to port P, in well-known fashion. 
     Combining the Precursor Calls— FIG. 10  depicts a flowchart of the salient task performed by the illustrative embodiment in accomplishing task  308 . 
     At task  1001 , private-branch exchange  104  answers the first precursor call (i.e., from telephone number T to telephone number D), in well-known fashion. 
     At task  1002 , private-branch exchange  104  merges the third precursor call (i.e., from telephone number D to port P) with the first precursor call, in well-known fashion. 
     At task  1003 , private-branch exchange  104  merges the second precursor call (i.e., from port P to telephone number D, extended to telephone number C) with the already-merged first precursor 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.