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As depicted in Figure 4.10, CTI is used in call center applications to effect enhanced functionality. Not only can the call be transferred and conferenced through computer keyboard and mouse commands, but the incoming call identification (calling number or PIN number) can be matched to a caller profile contained in a computer database. Through a screen pop, the callers profile is presented to the agent in advance of the call, improving customer service. Should the original agent need to transfer the call to another, the user profile and all other relevant data is transferred along with the voice call. This application was presented in greater detail in the previous discussion of Automatic Call Distributors (ACDs) [4-28].
Figure 4.10 CTI employed in conjunction with an ACD, in a call center environment. (Reprinted with permission from Call Center Magazine).
The technology concept involves Electronic Common Control (ECC) switches, computer systems, and application software. The switches can be PBXs, electronic KTSs, Hybrids, ACDs, or Centrex COs. The application software is written by third-party developers in accordance with Application Programming Interfaces (APIs). Defined by the equipment manufacturers, such interfaces permit a great deal of flexibility, incorporating user-definable call handling parameters. The computers can be in the form of mainframes, midranges, or PCs; LAN and Client/Server configurations are commonplace. The first generation of APIs were IBMs CallPath Systems Architecture (CSA), Digital Equipment Corporations Computer Integrated Telephony (CIT), and Hewlett-Packards Applied Computer Telephony (ACT), all of which still are widely used. Early implementations involved little more than switch-to-host request and status links. More recently, CTI has progressed to the point that it offers robust workstation-based intelligence. Other standards and specifications that have gained wide acceptance include CSTA, TSAPI, TAPI, MVIP, SCSA, and CAPI [4-7] and [4-29].
Computer Supported Telephony Applications (CSTA)
These applications developed by the European Computer Manufacturers Association (ECMA) were the first true open CTI development standard for link-level protocols. CSTA was improved and formally standardized on an international basis by the ITU-T, incorporating the U.S.-developed Switch-to-Computer Applications Interface (SCAI). CSTA is a full protocol stack, which requires an open system interface to a PBX, ACD, or Centrex CO exchange. CSTA is implemented by a growing number of manufacturers, including Alcatel, Comdial, Ericsson, Inter-Tel, Rolm Siemens and Tadiran. Closely aligned with CSTA are Lucent Technologies Adjunct/Switch Applications Interface (ASAI), and IBMs CallPath Services Architecture (CSA).
Telephony Services Application Programming Interface (TSAPI)
Developed jointly by AT&T and Novell and released in March 1994, TSAPI, a specification strongly oriented toward PC platforms, is a lesser protocol stack that does not require that the switch manufacturer fully open the interface. Although a number of PBX manufacturers supported TSAPI, which runs on Novell Netware servers and other systems, the cost of TSAPI PBX drivers is quite high and, as a result, its widespread use has been discouraged. Additionally, many suggest that it is limited in capability and cumbersome to use. TSAPI has been criticized as being a CSTA translator for AT&T Definity switches and as a means of promoting AT&Ts and Novells interests. Release 2 (1995) extended the API to other PBXs and computer systems, including OS/2, Macintosh, UnixWare, and Windows NT [4-30] and [4-31].
Telephony Application Programming Interface (TAPI)
TAPI is specification developed jointly by Microsoft and Intel in response to the problems associated with TSAPI. As an integral part of Microsofts Windows Open Services Architecture (WOSA), TAPI is being shipped with every copy of Microsofts Windows 95 and Windows NT. The client software makes a call to a server-based database in order to match the caller number to his profile. As it primarily is workstation-based, TAPI involves limited additional cost to the user organization [4-32], [4-30], and [4-31].
Multi-Vendor Integration Protocol (MVIP)
Developed in September 1990, MVIP is an ad hoc standard developed by Natural MicroSystems and supported on a multinational, multivendor basis. MVIP provides a set of telephony hardware and software standards for integrating diverse telephony technologies network interfaces and applications in a single adjunct computer system. MVIP was designed to overcome the limited call handling capabilities of PC busses, providing the ability to connect multiple telephony cards in a single PC and handle 256 simultaneous calls over 8 MVIP busses of 2 Mbps each. Multi-Chassis MVIP (MC-MVIP) extends MVIP to allow the interconnection of resources in up to 20 PCs, thereby providing additional flexibility and scalability. High capacity MVIP (H-MVIP) is in the development stages.
A number of vendors have linked together to support MVIP through the Global Organization for MVIP (GO-MVIP). Well over 50 manufacturers, including Mitel, have announced support for MVIP, and well over 200 products exist. Compatible products include Lotus Phone Notes and Nortels H.320 Desktop Video.
Signal Computing System Architecture (SCSA)
Developed by Dialogic, SCSA is supported by more than 200 suppliers and developers. A LAN/Server-based architecture, it is hardware independent at the client, host and media processing systems levels. Originally developed to support TAPI, it currently is interoperable with both TAPI and TSAPI. SCSAs SCbus (Signal Computing bus) allows the creation of up to 2,048 time slots per MVIP bus, thereby providing sufficient capacity for support of full-motion video and high-fidelity audio.
Common ISDN API (CAPI)
CAPI is an API developed in Germany for interfacing ISDN equipment to ISDN lines. Completed in 1990, CAPI is a well-established API which obviates some of the difficulties of interfacing such equipment to ISDN lines through NT-1/2s and Terminal Adapters (TAs).
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