Telephony applications use the same speech recognition engines used for Command and Control speech recognition, and the same text-to-speech engines used on the PC.
These hardware and software requirements should be considered when designing a speech application:
· Processor speed. The speech-recognition and text-to-speech engines currently on the market typically require a 486/66 or faster processor.
· Memory. On the average, the combination of speech recognition and text-to-speech will use 2 megabytes (MB) of random-access memory (RAM) in addition to that required by the running application.
· Telephony card. A number of telephony cards are on the market today. On the low end are cards that use FAX/MODEM chips which have been augmented to handle speech. These are included in almost every new home PC. Higher end cards include DSPs or support for multiple phone lines.
· Operating system. The Microsoft Speech application programming interface (API) requires either Windows 95 or Windows NT version 3.5.
· Speech-recognition and text-to-speech engine. Speech-recognition and text-to-speech software must be installed on the user's system. Many new audio-enabled computers and sound cards are bundled with speech-recognition and text-to-speech engines. As an alternative, many engine vendors offer retail packages for speech recognition or text-to-speech, and some license copies of their engines.
For a list of engine vendors that support the Speech API, see the ENGINE.DOC file included with the Speech Software Development Kit.