Abstract:
An apparatus and a method for establishing a telecommunications link controlled by a control program with a second communications terminal according to which a CTI service is made available to a first communications terminal by a CTI server in a CTI domain allocated to the CTI server and the second communications terminal is located outside the CTI domain and by way of a proxy situated within the CTI domain that is linked to the CTI server. The control program is linkable to the CTI server by way of an intermediate functional unit that can signal to the control program that the second communications terminal instead of the proxy is linked into the established telecommunications link as the telecommunications terminal. The intermediate functional unit can instruct the CTI server to carry out the CTI service on the proxy in accordance with the control program.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is the United States national phase under 35 U.S.C. §371 of PCT International Patent Application No. PCT/EP2014/001415, filed on May 26, 2014, and claiming priority to German patent application no. 10 2013 008 933.6, filed on May 24, 2013. 
     
    
     FIELD OF THE INVENTION 
       [0002]    Embodiments relate to methods for establishing a telecommunications connection between at least two terminals. Further embodiments relate to systems and methods for establishing a telecommunications connection. 
       BACKGROUND OF THE RELATED ART 
       [0003]    The integration of telecommunication networks and data networks is becoming increasingly important. Telecommunication networks are used primarily for communication by telecommunication subscribers using telecommunication terminals such as telephones. Data networks are used primarily for networking computers, for example PCs with servers. Methods and arrangements in which applications installed on computers control and monitor communication systems and communication connections are generally known as CTI solutions (CTI=Computer Telephony Integration). Both communication system ports and connections between ports can be controlled and monitored in this manner. The respective connections are temporary communication channels between two or more subscribers to one or more communication systems. 
         [0004]    When operating a CTI solution, data having control and status information are transmitted between a communication system and a CTI application (CTI application program). To this end, communication systems have special interfaces for the data exchange, CTI interfaces. The applications or PCs, respectively, likewise have corresponding CTI interfaces for this data exchange. The CTI interfaces of the communication system and those of the application are connected to one another via a data line or a data network for this purpose. Because the maximum number of CTI interfaces in a communication system is limited, a telephony server is often connected between the communication system and the applications. 
         [0005]    Publication WO 98/51092 A 1 “Computer telephony integration gateway” shows a public communications network with multiple communication systems and a private communications network with several domains, each having computers with applications for controlling and/or monitoring resources of the public communications network. The arrangement shown features a “CTI gateway” as a conversion device, which changes the type of data sent for controlling and/or monitoring resources from the public communication network to the private communication network, so that these data appear as the data from one single public communication network, and conversely changes the data that are sent by the applications from the private communication network to the public communication network as though they had been sent from a private communication network with only one application. 
         [0006]    DE 101 59 636 B4 describes a method for controlling and/or monitoring resources and connections using the exchange of data between communication systems and at least one application, wherein the data have identifiers that differentiate the resources and the connections, and the identifiers of the resources are converted during the exchange such that they present themselves as the identifier of one single communication system with subscriber connections for the one or for each application, characterized in that each of the identifiers of the connection between resources of different communication systems comprises one local connection number (call ID) of the communication system that participates in the connection and one global connection number (call ID) and in that through the conversion the global connection number (call ID) is transmitted to the application such that it cannot be differentiated by the application from a local connection number (call ID). 
         [0007]    At present, CTI services are accepted (executed) by a CTI server only if the associated device is located within the CTI domain. This means that devices outside the CTI domain can be addressed by an application only via their proxy (Trunk Device). 
       BRIEF SUMMARY OF THE INVENTION 
       [0008]    Embodiments relate to methods and apparatus for establishing a telecommunication connection with a second communication terminal, controlled by a control program, wherein a CTI server in a CTI domain that is assigned to said CTI server makes a CTI service available to a first communication terminal. Furthermore, embodiments relate to a system for establishing a telecommunication connection controlled by a control program comprising at least one CTI server and at least one communication terminal that is located in the CTI domain of the at least one CTI server. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0009]    The figures show: 
           [0010]      FIG. 1  schematically, a conventional arrangement of a CTI domain, i.e., with trunks as network interfaces; 
           [0011]      FIG. 2  schematically, an arrangement of system components for carrying out a planned call sequence process according to a currently familiar system (callcenter operation of OpenScape Office); 
           [0012]      FIG. 3  schematically, the system from  FIG. 2  later in the process (call switched to media server announcement); 
           [0013]      FIG. 4  schematically, connection changes for a single-step transfer according to the CSTA standard; 
           [0014]      FIG. 5  schematically, an implementation of the single-step transfer according to  FIG. 4  in the system from  FIG. 3 ; 
           [0015]      FIG. 6  schematically, a first arrangement of system components for carrying out an exemplary embodiment (single-step transfer) of a method according to the invention using an extra domain device; 
           [0016]      FIG. 7  schematically, a second arrangement of system components for carrying out an exemplary embodiment (single-step transfer) of a method according to the invention using middleware (CSP); 
           [0017]      FIG. 8  schematically, a third arrangement of system components for carrying out an exemplary embodiment (CallMonitoring) of a method according to the invention using an extra domain device; and 
           [0018]      FIG. 9  schematically, a third arrangement of system components for carrying out an exemplary embodiment (CallMonitoring) of a method according to the invention using middleware (CSP). 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0019]      FIG. 1  shows schematically a conventional arrangement including a CTI domain (switching SUB domain  10 ). This diagram is taken from the ECMA  269  (the standard CSTA model). A switching domain, a switching sub domain or a CTI domain is that region that is typically controlled by an application via CSTA. Shown in the center of  FIG. 1  is branch  14 , e.g., OpenScape Office. Terminals D 1 , D 2 , D 3 , the telephones, or the trunks leading to the Central Office (CO)  18  as well as D 4 , D 5 , D 6 , the network interface devices, are connected there. The case at hand shows trunks D 4 , D 5 , D 6  as network interface devices  12 . It does not matter whether the devices are analog terminals or ISDN devices. The same applies to the trunks, which can be analog trunks, ISDN trunks or SIP trunks. Other devices D 1 , D 2 , D 3 , together designated with the reference number  16 , are connected to PBX  14  within the domain  10 . In general, the (CTI) application can transmit commands to all devices connected to this system. 
         [0020]    This arrangement known from the prior art is carried out by transmitting the CTI service to the associated proxy (trunk device). This means that typical CTI applications use exclusively devices that are located within the CTI domain (switching SUB domain  10 ) for controlling, thus avoiding the problem of controlling a device directly, even if it is not located in the CTI domain. This problem may be addressed by the present invention. 
         [0021]    According to an embodiment of the invention, a method is provided for establishing a telecommunications connection, controlled by a control program, with a second communication terminal, wherein a CTI service is made available to a first communication terminal by a CTI server in a CTI domain that is assigned to said CTI server, wherein the second communication terminal is located outside the CTI domain and is connected to the CTI server via a proxy located within the CTI domain, wherein the control program is connected to the CTI server via an intermediate functional unit, wherein the intermediate functional unit signals to the control program that instead of the proxy, the second communication terminal is connected as the telecommunication terminal into the established telecommunications connection, and wherein the intermediate functional unit instructs the CTI server to carry out the CTI service on the proxy in accordance with the control program. 
         [0022]    Below, a voice connection is often used as a possible example of a telecommunication connection, but this should not be considered restrictive. 
         [0023]    One advantageous embodiment of the invention, which has features that can also be combined with features of other embodiments of this invention, provides that if the second communication terminal is not connected to the first communication terminal, the intermediate functional unit signals to the control program that a virtual third communication terminal instead of the proxy is connected as the communication terminal into the established telecommunications connection within the CTI domain. 
         [0024]    One advantageous embodiment of the invention, which has features that can also be combined with features of other embodiments of this invention, provides that the first voice connection is established between the first communication terminal and the second communication terminal, wherein the first voice connection is signaled to the control program as the first CTI service. 
         [0025]    One advantageous embodiment of the invention, which has features that can also be combined with features of other embodiments of this invention, provides that the method furthermore comprises specifying a second voice connection in place of the first voice connection, wherein the second voice connection is arranged between the first communication terminal and a third communication terminal. 
         [0026]    One advantageous embodiment of the invention, which has features that can also be combined with features of other embodiments of this invention, provides that the second voice connection corresponds to a second CTI service, wherein the CTI service appearing in the control program is the first CTI service. 
         [0027]    One advantageous embodiment of the invention, which has features that can also be combined with features of other embodiments of this invention, provides that each of the first and/or second voice connections corresponds to a proxy and that the at least one CTI server is configured to carry out the CTI service with the respective valid proxy without utilizing knowledge of the respective dynamically changeable proxy. 
         [0028]    One advantageous embodiment of the invention, which has features that can also be combined with features of other embodiments of this invention, provides that the intermediate functional unit is designed to transmit abstract data regarding the at least one CTI service to the control program via a proxy. 
         [0029]    One advantageous embodiment of the invention, which has features that can also be combined with features of other embodiments of this invention, provides that the at least one CTI server defines a CTI domain and that at least one of the communication terminals is located outside the CTI domain. 
         [0030]    One advantageous embodiment of the invention, which has features that can also be combined with features of other embodiments of this invention, provides that the change from the first to the second voice connection corresponds to either (i) a single step transfer or (ii) a change from CallMonitoring to the communication terminal connection. 
         [0031]    Embodiments may provide for a computer program product or a computer program for establishing a telecommunication connection. 
         [0032]    Embodiments may also provide for a machine-readable data carrier with a computer program product stored on the data carrier. 
         [0033]    Furthermore, embodiments may provide for an arrangement for establishing a telecommunication connection controlled by a control program and comprising a CTI server, a first communication terminal that is located in the CTI domain of the CTI server, a second communication terminal that is located outside the CTI domain of the CTI server, and a control device. 
         [0034]    Embodiments may solve the problem by the CTI server providing an abstraction level “Extra Domain Device” for the CTI server that is used to accept CTI services also without the aid or knowledge of the respective (dynamically changeable) proxy, even if the device is not located in the CTI domain. The CTI server then carries out this CTI service automatically at the respective valid proxy. 
         [0035]    The advantageous introduction of an abstraction level “Extra Domain Device” for carrying out CTI services at devices that are located outside the CTI domain allows the high-level application to forgo the (dynamic) proxy administration and instead concentrate on the actual device. A change in the logic (paradigm shift) is no longer necessary for CTI control. The high-level application retains the device to be controlled and a change to the proxy no longer takes place. The CSTA single step transfer example listed in the description can be applied to other CSTA services (Call Control and others). 
         [0036]    Embodiments are described below in more detail based on preferred exemplary embodiments and with reference to the figures. 
         [0037]    Embodiments of the invention are explained, for example, with reference to certain CTI-based telecommunication systems, namely OpenScape Voice or OpenScape Office, respectively. Such systems are created according to the CSTA standard (Computer-Supported Telephony Applications) of ECMA (http://www.ecma-international.org/activities/Communications/TG11/cstalll.htm). However, it is understood that different systems are available as the basis for implementing the invention. 
         [0038]    Unless stated otherwise, the individual design features of the system, combination of components, steps of the method or other techniques disclosed herein according to the embodiments of the present invention can be combined with any or all other design features of the system, combination of components, steps of the method or other techniques disclosed herein. 
         [0039]      FIG. 2  shows schematically an arrangement of system components for carrying out a planned call sequence process according to a currently familiar system (callcenter operation of OpenScape Office); In OpenScape Office, call A is placed in the waiting queue. 
         [0040]    The solution is further demonstrated using the example of the OpenScape Contact Center V9.0 by applying the CSTA service Single-Step Transfer and general call monitoring. Utilization of comparable services is conceivable. 
         [0041]    A. Planned Call Sequence with OpenScape Contact Center V9.0 Using OpenScape Office or OpenScape Smart Office. 
         [0042]    Essentially, the following components are involved in OpenScape Office or OpenScape Smart Office for the callcenter operation using the OpenScape Contact Center V9.0:
   Feature Processing (FP)   
 
         [0044]    The FP—a CTI server  20 —provides the queue and the call center distribution (UCD)  22  as well as its agents  24  (integral component of the communication servers or autonomous platform); in other words, Feature Processing is a telephone system, a partial system of OpenScape Office.
   Media Server (MS)   
 
         [0046]    Media Server  26  is connected to the CTI Server  20  via SIP.
   OpenScape Contact Center (OSCC)   
 
         [0048]    The callcenter application  28  is connected via CSTA and the MS API (Application Programming Interface) and distributes callcenter calls to announcements, agents (e.g., third terminal  24 ) and the queue. 
         [0049]    If a device is located in this OpenScape Office Domain or if a device that is not directly a part of this domain is to be controlled, then the application  28  must be notified to select a trunk, which in application  28  is not a fixed but a variable anchor. 
         [0050]    It is known that the OpenScape Contact Center (OSCC; transmission application) implements announcement handling for announcements (e.g., “Hello, welcome, please press “1” . . . ”) using analog terminals. A media server  26 , which is already used in OpenScape Voice, is inserted instead of the costly analog terminals (MS) into the overall system in another possible embodiment. Embodiments of the present invention use the latter. 
         [0051]    Initially (not shown in the figure), caller A is placed into the queue of the UCD  22  in the connection C 1  at the first terminal  36  (via PSTN and line Trk  1 ) in the FP (CTI server  20 ) of OpenScape Office or OpenScape Smart Office. When a call arrives (FP), the caller A (at the first terminal  36 ) reaches the platform via a trunk Trk 1 , is placed in a queue UCD 22  and waits there for further processing. The contact center (application  28 ) is notified about this via CSTA. The contact center (application  28 ) accepts the call, makes an announcement, and the call is then transferred from the first connection (connection  1 : C 1 ) to an analog announcement device. It is known to be an analog terminal, advantageously a media server  26 , and the insertion is carried out via SIP. 
         [0052]    As shown in  FIG. 1 , announcements are analog terminals and the announcement device is located in the switching subdomain  10 . An application (e.g., OpenScape Voice (OSV) or HiPath 8000—Softswitch from Unify GmbH &amp; Co. KG) always has access to it. In a future implementation, in which the media server  26  ( FIG. 2 ) is inserted via SIP, this is a connection via a network interface device (see right side in  FIG. 1 ), which means the media server  26  is not in but outside the CTI domain  10 ′. 
         [0053]    As shown in  FIG. 2 , the CTI domain  10 ′ is the FP (CTI server  20 ), and from the perspective of CSTA is not located inside domain  10 ′. The OpenScape contact center application  28  has a connection FP to CSTA and a different interface with the media server  26 . 
         [0054]      FIG. 3  shows schematically the system from  FIG. 2  later in the process. If no agent is available at the third terminal  24  or if a greeting announcement is to be played, then caller A is switched by the callcenter application  28  (OSCC) at the first terminal  36  out of the queue onto a SIP trunk (Trk  2 ) (using CSTA Deflect Call in the case of OpenScape Office and OpenScape Smart Office). 
         [0055]    Since media server  26  is connected via a native SIP, the call can be identified simply via the phone number. For this purpose, an extension is added by the OSCC for the transfer. 
         [0000]      Call=Dialing the media server+individual extension=&gt;D1 
         [0056]    The goal is an arrangement with which the call (C 1 ) leaves the FP  20  and is switched to the media server  26  for playing an announcement; an announcement device (second terminal D 1 ) is then located in the media server  26 . In the case at hand, this is accomplished via SIP. Since supplementary information cannot be transmitted via SIP, the announcement device D 1  is identified by an extension in the media server  26 . 
         [0057]    Example: When caller A dials “7007”, the call would arrive at “7007” on the media server  26  and with “510” the personal terminal, which corresponds to D 1 , would be reached. D 1 , D 2  or D 3  can be addressed by an extension via SIP. The call (C 1 ) is a selection of the media server  26  and an individual extension by which D 1  is identified. 
         [0058]    The CSTA Deflect Call command transfers the call from UCD  22  to the second terminal D 1  in the media server  26 . When this occurs, UCD  22  is not connected and caller A at the first terminal  36  has a connection from the trunk Trk 1  to the media server  26 . Application  28  then receives this information at CSTA trunk Trk 1  and trunk Trk 2 . 
         [0059]    For continued processing of the call (C 1 , . . . ), the application  28  would then have to check continuously on which trunk (Trk 1 , Trk 2 , . . . ) the call is taking place. This does not necessarily occur via trunk Trk 1  or Trk 2 ; it could also be trunk  3  or trunk  4 . 
         [0060]    The Deflect Call applied via CSTA is now a function of D 1 −f(D 1 ). 
         [0061]    The SIP trunk (Trk 1 ) then plays an announcement from the call center (OSCC) via MS. This is a fully qualified bidirectional communication. 
         [0062]    The call from caller A at the third terminal  24  is switched by the OSCC as f(D 1 ) to a SIP announcement of media server  26 . 
         [0063]    Once the announcement has been played, the call C 1  is to be passed on to an agent at the third terminal  24 . This is typically done using a single-step transfer. 
         [0064]    B. Single-Step Transfer 
         [0065]      FIG. 4  shows schematically connection changes for a single-step transfer according to the CSTA standard. Based on the presentation in  FIG. 3 , the CSTA service single-step transfer (SST) of the callcenter application  28  (OSCC) allows for the call C 1  to be switched from the SIP media server  26  to any desired target (e.g., agent at the third terminal  24 ). 
         [0066]      FIG. 4  is a diagram from ECMA-269: According to ECMA-269, this service should be represented on the devices (here Trk  2 =&gt;as function f(Trk 2 )) known to CSTA domain  10 ′. 
         [0067]    The single-step transfer call service transfers an existing connection C 1  from one device D 1  to another device D 3 .  FIG. 4  shows how terminal D 1  communicates with a terminal D 2  and releases a command “single-step transfer” from D 1  to terminal D 3 , causing D 2  to call D 3 . 
         [0068]    This transfer is carried out in one step, which means the device  2  that carries out the transfer must not guide the existing connection C 1  to the queue prior to the output of the single-step transfer call service. 
         [0069]    The state of the connection C 3  to be transferred can be alerting, connected, failed, held, or queued. 
       EXAMPLE 
       [0070]      
         [0000]    
       
         
               
               
               
             
           
               
                   
                   
               
               
                   
                 SIP-Trunk Trk 2 
                 FP 
               
               
                   
                   
               
             
             
               
                   
                 SingleStepTransferRequest 
                 Trk 2 C1 Agent FP Proxy Trk 2 ! 
               
               
                   
                 activeCall 
               
               
                   
                 deviceToTransferTo 
               
               
                   
                 SingleStepTransferResult 
               
               
                   
                   
               
             
          
         
       
     
         [0071]    However, the “level of knowledge” of the proxy at the call center application  28  is not ensured. 
         [0072]    A change in the logic (paradigm change) occurs from the perspective of the application  28 . 
         [0000]      The CTI service changes from f(D1)to f(Trk2). 
         [0073]      FIG. 5  shows schematically an implementation of the single-step transfer according to  FIG. 4  in the system from  FIG. 3 . Here, call A is switched by the OSCC  28  as f(Trk  2 ) from the media server  26  proxy trunk to an agent at the third terminal  24  ( FIG. 3  is a prerequisite). 
         [0074]    The SIP trunk (Trk  2 ) shown in  FIG. 5  determines the proxy to the announcement device D 1  of the media server  26 . While from the perspective of the call center application  28  the SIP trunk is a variable, potentially unknown quantity, the announcement device (second terminal D 1 ) of the media center  26  is a constant and always a known quantity from the perspective of the call center application  28 . 
         [0075]    Normally the “deflectCall” command would have to be “Trunk Trk 2  to agent” (third terminal  24 ). The problem is that the OSCC application  28  is actually configured such that it does not know anything about these trunks. The OSCC application  28  has one peculiarity: It is traditionally configured such that it recognizes only the following trunks: the true trunks of the central office  18 , the UCD  22  ( FIG. 1 ) and the agents (third terminal  24 ). This means that there are actually no statements about the call (connection) C 1 . The call C 1  is now at trunk Trk 2 , but the application  28  does not know trunk Trk 2 . According to the invention, this requirement has been solved. 
         [0076]    The following occurs from the application perspective of the application  28 : It places a Deflect Call to the second terminal D 1  and in the continued progress must control a trunk Trk 2 , which it may not know. 
         [0077]    The single-step transfer must occur onto the trunk Trk 2 . For the call C 1  of the media server  26  to get from terminal D 1  to the agent (third terminal  24 ), a single-step transfer command must occur at CSTA (application  28 ) for trunk  2 , whereupon the call C 1  moves to the agent (third terminal  24 ). 
         [0078]    The problem is now that the trunk is not known and that application  28  can only use components that it recognizes. The only one that application  28  knows in the case at hand is the second terminal D 1 . However, D 1  is not in the CTI domain  10 ′. The invention solves this problem that the application  28  can place the command onto D 1  even though D 1  is not in the platform (CTI domain  10 ′). 
         [0079]      FIG. 6  shows schematically a first arrangement of system components for carrying out an exemplary embodiment of a method according to the invention using an extra domain device  30 , namely for the case of a single-step transfer. Here, the call of caller A (first terminal  36 ) is switched by the OSCC as f(D 1 ) from the announcement device SIP media server  26  to an agent (third terminal  24 ) (prerequisite is again  FIG. 3 ). The implementation occurs as described above with reference to  FIGS. 1-5 , with the exception of the implementations below. 
         [0080]    The second terminal D 1  is located outside the CTI domain  10 ′; thus, the extra domain device  30  is provided according to the invention. The extra domain device  30  initially allows the system to recognize/check whether (i) a device D 1  is connected, (ii) it is a valid D 1 , (iii) where the proxy is located, (iv) the statuses for the proxy are correct and (v) how the command is implemented on the proxy. 
         [0081]    In the case at hand, the call (C 1 ) was queued at the UCD and the application  28  determined “deflect call to D 1 ”. The application  28  now issues the command to return the call and to carry out a “single-step transfer D 1  to the agent”. The new layer (domain device  30 ) now determines for the D 1  the dynamic internal trunk, which the application  28  does not yet recognize. Now, the application  28  knows only the UCD  22 , the third terminal  24  of the agent and the D 1 . This interim layer assumes the trunks. 
         [0082]    The abstraction level “extra domain device” introduced here can carry out its task also directly in the CTI server  20  (FP). This is sensible primarily within a network (e.g., via SIP-Q), where a callcenter application  28  serves several nodes at the same time. 
         [0083]    With the introduction of an abstraction level the CTI server  20  (FP) provides a capability for the CTI services that is used to accept CTI services also without the aid or knowledge of the respective (dynamically changeable) proxy, even if the device D 1  is not located in the CTI domain  10 ′. The CTI server  20  then carries out this CTI service automatically at the respective valid proxy. 
         [0084]    From the perspective of the callcenter application (OSCC)  28 , this results in the following CTI call-up to an extra domain device that is unknown in the CTI domain  10 ′ (here: D 1 =&gt;as function f(D 1 )): 
         [0000]    
       
         
               
               
             
               
               
               
             
           
               
                   
               
               
                 SIP-Trunk Trk 2 
                 FP 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 SingleStepTransferRequest 
                   
                 Media Server Device D1 
               
               
                 activeCall 
                 D1 C1 
               
               
                 deviceToTransferTo 
                 Agent 
               
               
                 SingleStepTransferResult 
               
               
                   
               
             
          
         
       
     
         [0085]    This call-up is now carried out automatically for the proxy within the abstraction level “extra domain device”  30 . 
         [0086]    Now, no change in the logic (paradigm change) occurs from the perspective of the application. 
         [0000]      The CTI service remains f(D1). 
         [0087]    Thus, with the aid of this abstraction level (extra domain device  30 ), a first CTI service (SST:f(D 1 ))  40  is signaled via CSTA between extra domain device  30  and application  28  and a second CTI service (SST:f(Trk  2 ))  42  is signaled via CSTA between extra domain device  30  and CTI server  20 . 
         [0088]    The tasks of this abstraction level “extra domain device”  30  are:
       Evaluation D 1     Checking the existence of D 1     Determining the (dynamic) proxy Trk  2     Plausibility check   Implementation on the proxy Trk  2 .       
 
         [0094]      FIG. 7  shows schematically, a second arrangement of system components for carrying out an exemplary embodiment (single-step transfer) of a method according to the invention, i.e., application in the network with additional middleware  32  (CSP); In this case of OpenScape Office and OpenScape Smart Office, it is a CSP (CSTA service provider). 
         [0095]    According to certain embodiments of the invention, the middleware networks with several layers (Trk 1  and Trk 2 ). According to current middleware technology, they are presented as only one switch. The switches (Trk 1  and Trk 2 ) do not know of the networking and of the multiple nodes. Thus, the invention can be applied in the network, i.e., across nodes. 
         [0096]    A call can arrive via gateway nodes; the application  28  knows the trunk; the UCD  22  can be located in another node and the mediaserver  26  could be switched in at a third node (not shown). However, most often this works directly; the one or the other trunk is connected to the media server  26 , and it is not necessary for the media server  26  to know this trunk. The media server  26  only needs to know the D 1  again and then place the “single-step transfer” command from D 1  to the agent. 
         [0097]    C. Call Monitoring 
         [0098]      FIG. 8  shows schematically a third arrangement of system components for carrying out an exemplary embodiment of a method according to invention using an extra domain device  30 , in this case call monitoring. 
         [0099]    The use of the extra domain device  30  does not apply only to a special functionality/CTI service in the CSTA, rather it is generally applicable and can also be applied to the call monitoring CTI service as well as for incoming and outgoing calls. 
         [0100]    A message that a call has arrived at D 1  follows, and at the beginning a monitor point is set to the second terminal D 1 . 
         [0101]    In call monitoring, a monitor point can be set temporarily to the device that is located outside the CTI domain  10 ′. This type of application allows for registering changes in the communication, for example through a transfer after a callback into the callcenter (see section B). 
         [0102]    In  FIG. 8 , one subscriber at the fourth terminal  34  (e.g., switching location) is in a callback to the callcenter on the connection C 2 . The subscriber hears an announcement (see  FIG. 3 ) from the device D 1  of the media server  26 . The original call is retained at the connection C 1 . When this callback is passed on to the callcenter, the connection typically changes its value; a connection C 3  arises (see  FIG. 9 ). 
         [0103]      FIG. 9  shows schematically a third arrangement of system components for carrying out an exemplary embodiment of a method according to the invention using middleware (CSP) in the case of CallMonitoring. Here, a callback is switched to the callcenter (change of the connection). 
         [0104]    The detailed sequence is presented in Table 2. 
         [0000]    
       
         
               
             
               
               
               
               
             
           
               
                 TABLE 2 
               
             
             
               
                   
               
               
                 CSTA events for the “Extra Domain Device” 
               
             
          
           
               
                 Service and Events 
                 Device Trk 2 
                 Device Dn 
                 Comments 
               
               
                   
               
               
                 . . . 
                   
                   
                 The call has been 
               
               
                   
                   
                   
                 diverted from UCD 
               
               
                   
                   
                   
                 device D3 to OMS 
               
               
                 DeliveredEvent 
                   
                   
                 The call is 
               
               
                 connection 
                 Trk2 C2 
                   
                 alerting OMS Dn. 
               
               
                 alertingDevice 
                 Dn 
               
               
                 callingDevice 
                 Subscriber 
               
               
                 calledDevice 
                 UCD 
               
               
                 lastRedirectionDevice 
                 UCD 
               
               
                 localConnectionInfo 
                 Connected 
               
               
                 cause 
                 newCall 
               
               
                 MonitorStartRequest 
                   
                   
                 OSCC starts monitor- 
               
               
                 monitorObject 
                   
                 Dn C2 
                 ing OMS device Dn. 
               
               
                 MonitorStartResult 
                   
                   
                 Monitor on Device Dn 
               
               
                 crossReferenceID 
                   
                   
                 as a model of Trk 2 
               
               
                   
                   
                   
                 (optional) 
               
               
                 EstablishedEvent 
                   
                   
                 OMS answers the call 
               
               
                 establishedConnection 
                 Trk2 C2 
                 Dn C2 
                 and plays 
               
               
                 answeringDevice 
                 Dn 
                 Dn 
                 announcement. 
               
               
                 callingDevice 
                 Subscriber 
                 Subscriber 
               
               
                 calledDevice 
                 UCD 
                 UCD 
               
               
                 lastRedirectionDevice 
                 UCD 
                 UCD 
               
               
                 localConnectionInfo 
                 Connected 
                 Connected 
               
               
                 cause 
                 newCall 
                 newCall 
               
               
                 TransferredEvent 
                   
                   
                 Call is transferred. 
               
               
                 primaryOldCall 
                 Trk2 C2 
                 Dn C2 
               
               
                 transferringDevice 
                 Subscriber 
                 Subscriber 
               
               
                 transferredToDevice 
                 Dn 
                 Dn 
               
               
                 transferredConnection 
                 Trk 1 C3 
                 Trk 1 C3 
               
               
                   
                 Trk 1 C1 
                 Trk 1 C1 
               
               
                   
                 Caller A 
                 Caller A 
               
               
                 transferredConnection 
                 Trk 2 C3 
                 Dn C3 
               
               
                   
                 Trk 2 C2 
                 Dn C2 
               
               
                   
                 Dn 
               
               
                 localConnectionInfo 
                 Connected 
                 Connected 
               
               
                 cause 
                 transfer 
                 transfer 
               
               
                 . . . 
               
               
                   
               
             
          
         
       
     
         [0105]    A conversion from proxy trunk Trk  2  to the—from the perspective of the CTI domain  10 ′—external device Dn can take place additionally at the temporary monitor point for the “extra domain device”  32  (Dn). 
         [0106]    The advantageous introduction of an abstraction level “Extra Domain Device”  30 ,  32  for carrying out CTI services at devices that are located outside the CTI domain  10 ′ allows the high-level application  28  to forego the (dynamic) proxy administration and instead concentrate on the actual device. 
         [0107]    Thus, with the aid of this abstraction level (extra domain device  30 ), a first CTI service (MONITORING:f(D 1 , C 2 ))  44  is signaled via CSTA between “extra domain device”  30  and application  28 , and a second CTI service (SST:f(Trk 2 ), MONITORING:f(Trk 2 ))  46  is signaled via CSTA between “extra domain device”  30  and application  28  and CTI server  20 . 
         [0108]    A change in the logic (paradigm shift) is no longer necessary for CTI control. The high-level application  28  retains the device to be controlled and a change to the proxy no longer takes place. 
         [0109]    The examples of CSTA single-step transfer and call monitoring provided here can also be applied to other CSTA services (call control and others). 
         [0110]    The extra domain device  30  can be an extra server, middleware or software, or can be implemented on the platform. 
         [0111]    Single-step transfer and call monitoring are only examples of various functionalities that can be simplified by the invention. 
         [0112]    One advantage is that the high-level application  28  does not need to concern itself about where the limits of the CTI domain  10 ′ are. It can utilize the fact that other devices can be controlled by the application  28  as well, although they are located outside the CTI domain  10 ′, without having to concern itself with which additional resources are used internally in the call processing in this platform, how to address them, etc. This is taken away from the application  28 , thus making the function simpler. 
         [0113]    In addition to the two examples mentioned above (call monitoring and single-step transfer), there are other functionalities where this abstraction level could be advantageous, e.g., device monitoring of the CSTA. 
         [0114]    It should be noted that the features of the invention described by referencing the presented embodiments, for example CTI server, media server, control program (application), data structures, extra domain device (the type and configuration of the used parameters, control commands, protocols and hardware components, the arrangement of the individual components in relation to each other or the sequence of the respective process steps) can also be present in other embodiments or variations hereof, unless stated otherwise or prohibited for technical reasons. Not all features of individual embodiments described in combination must necessarily always be implemented in any one particular embodiment. 
       ABBREVIATIONS 
       [0115]    ACD Automatic Call Distribution 
         [0116]    API Application Programming Interface 
         [0117]    CSTA Computer Supported Telecommunications Applications 
         [0118]    C 1 , C 2 , C 3  Connection 
         [0119]    D 1 , D 2 , D 3  (Subscriber) Device 
         [0120]    ECMA-269 Standard ECMA-269. Services for Computer Supported Telecommunications Applications (CSTA) Phase III. 9th edition (December 2011). 
         [0121]    FP Feature Processing 
         [0122]    f( . . . ) Function of . . . 
         [0123]    MS Media Server 
         [0124]    OSCC OpenScape Contact Center 
         [0125]    PSTN Public Switched Telephone Network 
         [0126]    SIP Session Initiation Protocol 
         [0127]    SIP-Q Network Protocol CorNet-NQ tunneled via SIP 
         [0128]    SST CSTA Service Single Step Transfer 
         [0129]    Trk 1 , Trk 2  (Network) Trunk 
         [0130]    UCD Universal Call Distribution (ACD solution of the OpenScape Office and OpenScape Smart Office) 
       LIST OF REFERENCES WITH FEATURES 
       [0131]      10 ,  10 ′ CTI Domain 
         [0132]      12  Network Interface Device 
         [0133]      14  Branch/PBX 
         [0134]      16  Device 
         [0135]      18  Central Office 
         [0136]      20  CTI Server 
         [0137]      22  Callcenter Distribution/UCD 
         [0138]      24  Third Communication Terminal/Agent 
         [0139]      26  Media Server 
         [0140]      28  Control Program 
         [0141]      30  Intermediate Functional Unit/Abstraction Level 
         [0142]      32  Intermediate Functional Unit 
         [0143]      36  First Communication Terminal/Caller 
         [0144]      40  First CTI Service 
         [0145]      42  Second CTI Service 
         [0146]      44  First CTI Service 
         [0147]      46  Second CTI Service