Subject: [Speechsc] Problem with DTMF type-ahead

From: "Reifenrath, Klaus" <[email-masked]>
Date: Tue, 23 Aug 2005 11:41:05 -0400

The MRCP and MRCPv2 specifications define how DTMF input should be handled:
DTMF input is collected after the RECOGNIZE request is received until a
term-char or timeout is reached. Then a result or no-match is returned based
on any active DTMF grammars. The problem is there can be a significant
amount of time between when one result is processed by the application and
the next grammar is activated. During that time any DTMF input received will
be lost. Such DTMF type-ahead is common for frequent users of IVR systems,
and buffering that type ahead is required by VoiceXML 2.0 (see section
4.1.8). Can this requirement of VoiceXML be implemented using MRCP (assuming
that the media source CANNOT buffer DTMF)? If so, how is it done? 
Thanks,
Klaus

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From: "Dave Burke" <[email-masked]>
Date: Tue, 23 Aug 2005 20:29:10 +0100

Problem with DTMF type-aheadNice catch. This is a must fix in my opinion.

Here's my thought on a resolution:

By default, the recognizer (dtmfrecog or speechrecog) should buffer DTMF. This means that if some DTMF digits are entered outside of the Recognizing State and a RECOGNIZE request made later, the buffered digits and their timings are applied to that recognition. To clear the buffer, a header can be added to RECOGNIZE called Clear-DTMF-Buffer: true. Any DTMF digits buffered up to that point are discarded. 

Can supply the text changes if that's helpful (also note small refactoring needed in last sentence of section 9.9 regarding not buffering anything before RECOGNIZE). 

Dave

  ----- Original Message ----- 
  From: Reifenrath, Klaus 
  To: [email-masked]' ; [email-masked]' 
  Cc: [email-masked]' 
  Sent: Tuesday, August 23, 2005 4:41 PM
  Subject: [Speechsc] Problem with DTMF type-ahead 

  The MRCP and MRCPv2 specifications define how DTMF input should be handled: DTMF input is collected after the RECOGNIZE request is received until a term-char or timeout is reached. Then a result or no-match is returned based on any active DTMF grammars. The problem is there can be a significant amount of time between when one result is processed by the application and the next grammar is activated. During that time any DTMF input received will be lost. Such DTMF type-ahead is common for frequent users of IVR systems, and buffering that type ahead is required by VoiceXML 2.0 (see section 4.1.8). Can this requirement of VoiceXML be implemented using MRCP (assuming that the media source CANNOT buffer DTMF)? If so, how is it done? 

  Thanks,
  Klaus 

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