Introduction To Line Telecommunications

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12. Proprietary Devices


12.1 Interfaces

  12.2 - Support Equipment

12.3 - External Equipment

12.4 - Computer Telephony Integration (CTI)

12.3 - External Equipment

External equipment provides additional features to the system in their own right. These are features that are not otherwise present on the system. Examples are the Voicemail systems covered earlier in this book, voice announce units and music on hold sources.

12.4 - Computer Telephony Integration (CTI)

Computer Telephony Integration (CTI) is a relatively new facility becoming available on a widening range of telephone systems.

In simple terms it is a method of connecting the system to a computer and for these to work as an integrated unit. Using these interfaces has made it possible to provide much enhanced functionality to the users. These new facilities have begun to open up new application areas whose limits will be defined only by the ingenuity of the developers and willingness of the customers to pay for them.

The link is achieved with a combination of hardware and software provided by or in association with the system
manufacturer. The hardware is usually an interface card for the system and/or the PC. The system software will be able to operate the card when it is installed, and there will be software for the computer to allow it to communicate with the system via the interface.

12.4.1 - Telephone Applications Programming Interface (TAPI)

The most basic of these is the Telephone Applications Programming Interface (TAPI) which connects individual
computers to the system, usually using the proprietary extension port and allowing the computer to have access to basic system functions and control of the extension port when required. TAPI is a Microsoft protocol, which is currently at version 2, with version 3 due to become available in early 2000.

The protocol is a series of software functions and calls which allow the application to use the operating system to interact with the telephony connection.

12.4.2 - Telephone System Applications Programming Interface (TSAPI)

The Telephone System Applications Programming Interface (TSAPI) is more sophisticated link between the telephone system and a computer. In this case the link is directly from the CCU of the telephone system to a network server which allows integration of the functions of the telephones and computer network on a system wide basis from the one connection.

The level of integration is such that Unified Messaging System functions can be combined in a single application. Control can be from the users’ computer and/or extensions. It can also enable transmission of call data such as Calling Line Identity (CLI) from system to system so that as the user’s ‘phone rings their terminal presents them with a database record containing information about the caller if they have called previously.

12.4.3 - Proprietary Application Programming Interface (PAPI)

TAPI and TSAPI are 'open' interface protocols. Developers can obtain and use the specifications and be confident that the applications they create will be compatible with other equipment following the standard. Proprietary Application Interfaces (PAPI) are created for a single system, usually by the manufacturer. They have the advantage of being more highly integrated with the system than TAPI and TSAPI as they are not required to adhere to the standards defined for these interfaces. The disadvantage is that the applications developed for them cannot be used on other platforms and the programmers will need to learn them before creating the applications.





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Extracted from

Introduction To Line Telecommunications
Copyright Panasonic Business Systems UK Ltd 2000