Abstract:
An improved computer telephony (CT) server which utilizes a standard message structure to communicate with applications, but may interface such applications to a variety of different telephony environments by translating the standard message structure used by such applications into the specific message structure required by each such telephony environment. The aforementioned telephony environments may include PBXs, ACDs, packet telephony environments and public switched telephone networks. The desired telephony environment may be chosen by the application, or by the computer telephony server, some combination of both, or entirely automatically.

Description:
TECHNICAL FIELD 
   This invention relates to telephony, and more particularly, to an improved computer telephony server that is capable of easily and conveniently interfacing with a variety of computer telephony environments, on a dynamic basis if necessary. 
   BACKGROUND OF THE INVENTION 
   The industry of computer telephony has experienced extensive growth over the last several years. One aspect of computer telephony involves software computer telephony applications which communicate over a local area network (LAN) or computer bus with a computer telephony (CT) server. The CT server then communicates with a private automated branch exchange (“PABX” or “PBX”) for the purpose of implementing certain computer telephony functions. For example, “screen pop” is an example of a computer telephony application which may run on a personal computer (PC) and which may be implemented using a computer telephony server. In such an arrangement, a caller who dials in to a call center would have his telephone number read by a PBX. The telephone number is then forwarded through a local area network to a CT application program, which utilizes a table look-up in order to map the telephone number to a particular account number and account information. The account information is then read from a database and placed upon a computer screen to make it available to an agent for handling the incoming telephone call. 
   U.S. Pat. No. 5,414,762 assigned to Q-sys describes a computer telephony server that can be implemented as a layer of software and assists with the interface between various PBXs and applications. Specifically, as described in the Q-sys patent, each of the variety of PBXs available on the market today may have differences in its command set, message structure and other features. Accordingly, it is highly desirable that applications developers who write CT applications be able to write such applications independent of the particular PBX being utilized. Otherwise, each time an application is to work with a different PBX, the application would have to be rewritten. 
   The foregoing Q-sys patent solves the problem by offering a CT server that is capable of communicating with a variety of PBXs available on the market. The Q-sys telephony server has a standard message structure for communicating with applications over a local area network or a computer bus. Additionally, the arrangement taught by the Q-sys patent provides a means for translating the messages received from CT applications into the particular language and message structure of the particular PBX being utilized by the system. 
   The arrangement of the Q-sys patent provides a solution to the problem that applications developers used to face, namely, that each time their application was connected to a different PBX, it would have to be rewritten in order to understand and interpret the particular message structure, protocol, etc., of the PBX. By utilizing the Q-sys technique, a common language can be used by all applications, and a layer of independence is achieved between the CT application and the PBX. Systems like that taught by the Q-sys patent were available nearly ten (10) years ago from Digital Equipment Corporation. 
   One problem with the Q-sys arrangement is that it does not take into account the fact that a PBX is only one particular type of telecommunications system capable of establishing a call between users. Specifically, the Q-sys system, while being capable of communicating with a variety of PBXs, is limited to situations where a PBX is the means by which arriving telephone calls are connected to users. In view of the foregoing, there exists a need in the art for an improved CT server which can operate in an environment where there are not only PBXs being utilized to establish calls between users, but rather, where a variety of telephony systems (packet telephony networks, public switched telephony networks, etc.) may be utilized alternatively or simultaneously to construct such cells. 
   SUMMARY OF THE INVENTION 
   The foregoing and other problems of the prior art are overcome in accordance with the present inventions which relates to a method and apparatus for interfacing from computer telephony applications to a variety of computer telephony environments. In accordance with the present invention, a computer telephony server is utilized which provides a standard language for communicating with the call control mechanisms of a plurality of diverse telecommunications environments (such as PBXs, automatic call distributor (ACD) systems, Internet telephony environments, public switched telephone networks, etc.), and translating service requests and call status information between the standard instruction set utilized by the CT applications and the specific instruction set required by each telephony environment. 
   The server may be configured to communicate by means of the language and message structure of any of such diverse telecommunications environments through configuration instructions issued by the CT application operating on a remote computer. Alternatively, manual configuration of the server via human intervention may be used. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  shows an architectural diagram of the exemplary embodiment of the present invention as used in a multiple telephony environment system; and 
       FIG. 2  shows an exemplary embodiment of a data network telephony environment with which computer telephony server  102  of  FIG. 1  may work. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 1  shows an exemplary system in which the computer telephony server of the present invention may be used. The arrangement of  FIG. 1  includes one or more applications  101 , the inventive computer telephony server  102 , and telephony environments  103  through  106 . In the exemplary telephony environments shown, an Internet telephony environment  104  is included, as well as a PBX  105 , the public switched telephone network (PSTN)  106 , and an open switching system ( 103 ) built upon a CT media platform. The CT media platform is an open, general-purpose hardware and software platform suitable for the construction of media processing and switching systems. A representative CT media platform is available from the assignee of the present invention, and commercial implementations of switching systems built upon that platform are likewise available from their respective developers. 
   It is understood that the applications  101  may be any of a variety of computer telephony applications, such as screen pop applications, voice processing systems, etc. Other possible applications include call routing (determining to whom or to what system an incoming call should be routed) and database driven dialing, whereby an automated dialing application calls a predetermined set of telephone numbers listed in a database. Any one or more of these applications may require communications with CT server  102 , as is conventional in the art. 
   In operation, information is exchanged between applications  101  and CT server  102 , and between CT server  102  and one or more of the plurality of computer telephony environments  103  through  106 . For purposes of explanation herein, and not limitation, the example of a screen pop application  101  is utilized. In such an application, a telephone call is received through one of the telephony environments and delivered to the telephone instrument associated with a user of the screen pop application. Simultaneously, information about the arriving call is sent by the telephony environment (in its specific instruction set) to the CT server, which in turn forwards the information to the CT application (in the application&#39;s selected standard instruction set). The application discovers the caller&#39;s identity according to the existing computer telephony art by inspecting the automatic number identification (ANI) information or other user-entered data such as an account number. The CT application  101  uses this information to retrieve appropriate records from a business application database and presents the information to the user to expedite further interactions with the caller. 
   The information exchanged between the telephony server and the application relates to instructions which the application requires the computer telephony server to execute, as well as to status messages which are returned from the computer telephony environment (e.g., PBX  105 ) to the application  101 . The computer telephony server  102  is arranged to be configurable for communicating with any of the variety of computer telephony environments. Additionally, such configuration may be done when the system is initially installed, or may be done on a dynamic basis, perhaps through commands issued by a particular application. 
   For example, an application may be capable of establishing telephony calls between its associated user and a remote party via a PBX or via the public switched telephone network. The application specifies, as part of its initial communication with CT server  102 , the particular telephony environment desired. Computer telephony server  102  then translates all appropriate messages between application  101  and the selected telephony environment,  103  through  106 . Such messages are translated into appropriate commands and message structures which are applicable to either the PBX or the public network, as specified. The particular application may operate exactly the same regardless of whether the computer telephony environment is a PBX or a public network, or any of the other available environments. Additionally, if the application does not provide for such a selection, such a selection may be done automatically or in accordance with an operator program selection criteria and computer telephony server  102 . Such an arrangement makes the application completely unaware of the commands and message structures of the particular telephony environment, and thus applications need not be rewritten each time the particular telephony environment is changed. 
     FIG. 2  shows a slightly more detailed diagram of the interconnection between the CT server  102  and a packet telephony network  104 . As shown in  FIG. 2 , CT server  102  communicates with a gatekeeper  201  installed within the packet telephony network and configured according to the packet telephony art to supervise calls between the endpoints of interest to the CT application. The gatekeeper implements, for example, the H.323 protocols defined by the International Telecommunications Unit (ITU) for this purpose. Within the packet telephony environment, the gatekeeper  201  is responsible for supervising the establishment and disconnection of calls between endpoints within the packet telephony environment, such endpoints comprising both gateways  202  and  203  (points of entrance and egress from the packet telephony environment to other telephony environments such as the public switched telephone network) as well as telephone instruments  207  and  208  (connected directly to the packet telephony environment). 
   When so directed by one of the applications  101  (using the standard instruction set selected by the application), CT server  102  communicates over a data network with the gatekeeper  201  (using the specific instruction set required by gatekeeper  201 ) requesting gatekeeper  201  to establish, disconnect, or take some other action with respect to calls within the gatekeeper&#39;s domain of supervision. Gatekeeper  201 , in turn, utilizes the H.323 instructions specified by the ITU to implement the required operations within the packet telephony environment such as establishing internet telephony calls among end user telephones  205  through  208 . 
   Note that the use of Internet telephony and gatekeeper  201  is entirely transparent to applications  101  and whether such telephony environment is used or whether the connection is set up through a PBX CT media or public switched telephone network need not concern an application. Accordingly, the same application can be utilized together with a variety of telephony environments. 
   The above describes the preferred embodiment of the invention. It is understood that various modifications or additions will be apparent to those of skill in the art. Such additions are intended to be covered by the claims appended hereto.