There’s Nothing Phony About Telephony

Webster's dictionary defines telephony as "the science of communication by telephone." Unfortunately, this definition isn't very useful because these days "communication by telephone" covers a wide range of technologies--voice, fax, data, video, and pager communications all fall under the heading of telephony. This article broadens that definition by exploring telephony technology and its application in the Windows NT environment.

The Scope of Telephony
For years telephony services were handled by self-contained, proprietary hardware devices. These devices include telephones, videophones, pagers, dedicated fax machines, Private Branch eXchange (PBX) controllers, and more. During the mid-1980s, key telephony companies introduced telephony hardware and software solutions to commercial and personal computers. This means that UNIX systems--and now Windows NT Servers--can become PBX systems, and PCs can operate as phones, fax machines, and answering machines.

The integration of telephony and computers is called Computer Telephony Integration. CTI applications range from simple in-the-home phone solutions to full-scale enterprise-wide business solutions. For example, low-end CTI solutions enable you to:

• Use a computer as a single-line answering machine or voice mailbox
• Use a computer as a send/receive fax machine (In the world of CTI, the integration of computers and fax technology is called Computer-Based Fax, or CBF.)
• Use the microphone/speaker or speakerphone facilities on a multimedia computer as a phone system (If you're considering this application, be aware that it requires support for full-duplex audio operation--concurrent audio in and out--which is not normally available on most PCs.)

This level of CTI technology works well in home and small-business environments. Implementing CTI solutions for large corporate environments, however, requires a different level of technology. You need a highly reliable platform; you need better physical interfaces to the phone system; and you need more sophisticated CTI software to tie it all together. The payoff for this sophistication is a range of CTI solutions that enable you to:

• Use a computer system as either a multiline phone system or a multifunction PBX controller
• Implement an enterprise-wide voice-mail system in conjunction with--or as a replacement for--existing PBX equipment
• Set up on-demand audio information services that allow callers to retrieve prerecorded or computer-generated text-to-speech (TTS) information based on either touch-tone keys or actual voice input
• Set up on-demand fax services based on touch-tone keys or voice input that transmit information back to the caller
• Implement automatic, list-based dialing for telemarketing
• Deliver computer-based data related to a call (e.g., account balance, sales history, customer profile) to the desktop computer at the same time the call is switched to the desktop phone
• Set up one or more network-based fax servers that can route inbound and outbound fax transmissions to and from desktop systems on the network
• Implement on-screen, two-way voice/video conferencing
• Create a single, easy-to-use front end for managing all methods of communicating with an individual, such as voice, pager, or email

Implementing these kinds of solutions requires more than a garden-variety PC with a single fax/modem attachment.

CTI Platforms
Traditionally, enterprise-oriented CTI solutions have been based on stand-alone PC systems (DOS, Windows, or OS/2), NetWare servers, or UNIX platforms. These platforms offer a well-defined operating environment and standardized I/O buses to handle specialized telephony adapters. Recently, CTI vendors have embraced the Windows NT environment as the newest--and often preferred--platform for their CTI solutions because it offers several key benefits:

• NT offers proven stability and reliability. CTI applications tend to be mission-critical functions where reliability is a major consideration.
• Most telephony adapters support the ISA bus. Thus, Intel-based NT systems have access to a wide variety of telephony adapters because the software drivers for those adapters have been ported to the NT environment.
• NT provides an excellent development and runtime environment. It supports a broad range of development tools, and its graphical orientation can facilitate easy-to-understand user interfaces.
• The integrated network services in the NT environment offer flexible ways of distributing CTI functions and information across a network.
• The BackOffice suite of products provides a wealth of integration possibilities. CTI applications can be linked with Microsoft SQL Server, Mail Server, and Exchange Server. Many CTI vendors claim that telephony is another legitimate BackOffice function.