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The Technology

Voice processing systems are specialized computer systems consisting of ports, processors, an operating system, codecs, and storage. The computer platform typically is special-purpose, although it may be a general purpose computer with special application software. The operating system may be UNIX or some other industry standard, although it often is proprietary. Similarly the processors may be Intel or another industry standard, or they may be proprietary. The codecs serve to convert incoming analog signals to digital format, compressing the data in the process in order to conserve expensive system storage. Disk drives contain application programs and provide for storage of data, including digitized voice greetings, and incoming messages which are stored in individual mailboxes in the form of memory partitions. The amount of storage is sensitive to factors such as the number of mailboxes, the number of messages to be stores, the average message length, the nature of the analog-to-digital conversion process and compression rate, and the number of messages to be archived.

A customized voice greeting provides the calling party with options that are invoked through either DTMF selection or voice recognition; voice recognition is not common at this time. The subsequent voice input can be either analog or digital, depending on the nature of the connecting circuit. The voice processing system then digitizes and compresses the signal, as required, employing a proprietary code format and compression scheme.

Interface to a PBX, Hybrid PBX, ACD, or Central Office generally is required. In the case of a PBX, Hybrid or Central Office application, the voice processing system generally is accessed from the switch in the event of a busy or no-answer condition at the intended target station. Alternatively, the voice processing system can act as an Automated Attendant. The switch answers the call and forwards it to the voice processor, which allows the caller to access a department or station through interaction with an options menu and automated directory. The voice processor then signals the switch, instructing it to connect the call. Interface to a general purpose computer system is also commonplace. In such an application, the system allows database access, with the response being in the form of text-to-speech, which is synthesized.

Networking of voice processing systems (Figure 5.2) is fairly routine in large organizations, although it is generally limited to systems of the same origin (manufacturer) and generic software load. In a networked environment, multiple systems are connected via dedicated system ports; the nature of the network varies widely, although digital networks are preferred as the information is in data format. On a scheduled basis, the various systems will engage in a computer-to-computer dialogue, transferring messages to the systems on which reside the destination mailboxes.


Figure 5.2  Networked voice processing systems, with PBX, Centrex, and host interfaces.

Platforms for voice processing no longer are limited to proprietary hardware, although that is still the case with larger systems for intensive applications. Many smaller organizations and those with certain, specific applications currently make use of special software and voice cards (printed circuit boards) which reside on 486 PC platforms in a client/server environment. CallWare Technologies offers a Novell NetWare client/server application software package that includes an automated attendant, audiotex, customized mailboxes and tenant services. Such a CTI approach is highly functional and very cost-effective, although issues of reliability and database integrity cause lingering doubts as to the wisdom of placing such an applications suite on a general-purpose computer. Additionally, the voice message takes up substantial amounts of memory. In a recent Network World test, the CallWare software required 22 Kb of memory for each second of a voice message, yielding a 55 KB storage requirement for a typical 20-second message [5-16].

Interoperability standards recently have increased the power of voice processing through enabling the internetworking of systems. AMIS (Audio Messaging Interface Specification) enables the exchange of messages between unlike systems.

Applications

Applications for voice processing have increased dramatically with penetration having reached the point that it is virtually everywhere. Typical applications can be categorized as voice mail, audiotex, call processing, and database access [5-17] and [5-18].

Audiotex

Audiotex is a simple technology by today’s standards, allowing callers to select prerecorded messages from a menu. Essentially a voice bulletin board, audiotex generally is incorporated into a more substantial suite of voice processing applications such as call processing; with the audiotex feature perhaps allowing callers to select options on the telephone to gain information on hours of operation (Press 1), get directions to the company location (Press 2), gain access to recent press releases (Press 3), or determine the price of the stock at the close of the last trading day (Press 4).


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