DtmfRecognitionEngine Class

Provides access to DTMF recognition services.

Namespace: Microsoft.Speech.Recognition
Assembly: Microsoft.Speech (in microsoft.speech.dll)


Public Class DtmfRecognitionEngine
    Implements IDisposable
public class DtmfRecognitionEngine : IDisposable
public ref class DtmfRecognitionEngine : IDisposable
public class DtmfRecognitionEngine implements IDisposable
public class DtmfRecognitionEngine implements IDisposable


The DtmfRecognitionEngine class supports the use of speech-type grammars to analyze DTMF input. Its API is like that of SpeechRecognitionEngine, but its recognition input is a series of DTMF tones instead of an audio stream.

DtmfRecognitionEngine works by performing a series of emulated recognitions. It maintains a buffer with a list of tones that have been received. Every time a new tone is received, it appends the new tone to the list and emulates recognition of the whole list. This process continues until emulation produces a definitive result, or one of the timeouts is reached.

Inheritance Hierarchy


Thread Safety

All public static (Shared in Visual Basic) members of this type are thread-safe. Instance members are not guaranteed to be thread-safe.


Development Platforms

Windows XP Professional with Service Pack 2 (SP2), Windows Server 2003, Windows Vista Ultimate Edition, Windows Vista Business Edition, Windows Vista Enterprise Edition

Target Platforms

See Also


DtmfRecognitionEngine Members
Microsoft.Speech.Recognition Namespace