Posted: Thu Feb 22, 2007 3:20 pm Post subject: [asterisk-speech-rec] DTMF
Hi
I find that I'm not getting reliable results trying to detect DTMF using
Lumenvox SRE via Asterisk. In fact, I don't know if it really recognises
DTMF at all - sometimes it just happens to match against the voice grammar -
e.g. a beep is matched against spoken "yes". My application uses code like:
So users can say yes or no or press 1 or 2. However, it recognises speech
OK and but rarely DTMF. In the Lumenvox Engine documentation, I see
references to the built-in Boolean grammar being:
builtin:dtmf/boolean?y=1;n=2
but that doesn't make a difference.
In Call Browser, the call details don't show any DTMF events. Calls are
originated by Asterisk via a SIP/RTP provider, and we're getting DTMF as
out-of-band RFC2833. In the Asterisk recording, I can hear the tones have
been suppressed from the audio stream as expected, but in the Lumenvox Call
Browser, there are full-length tones, so I guess the Asterisk/Lumenvox
interface may be adding the audio tones back in, and the SRE should be
recognising the tones. Is that how it should work? Is there any special
configuration required to get DTMF passed through and recognised correctly?
Posted: Thu Feb 22, 2007 4:12 pm Post subject: [asterisk-speech-rec] DTMF
David Brazier wrote:
Quote:
Hi
I find that I'm not getting reliable results trying to detect DTMF using
Lumenvox SRE via Asterisk. In fact, I don't know if it really recognises
DTMF at all - sometimes it just happens to match against the voice grammar -
e.g. a beep is matched against spoken "yes". My application uses code
like:
Using the newest version of the speech API once a DTMF digit is received
then Asterisk will stop doing speech recognition and switch strictly to
DTMF in itself. Once this happens the SRE is no longer involved as it is
not the one who detects or handles the DTMF. If everything is properly
setup then DTMF tones should never reach the SRE. In the case where
you've got DTMF going inband and you're not setup to process it inband,
then it would spill over to the engine but that's the only case I can
think of.
Joshua Colp
Software Developer
Digium, Inc.
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Posted: Thu Feb 22, 2007 4:53 pm Post subject: [asterisk-speech-rec] DTMF
Joshua Colp wrote:
> Using the newest version of the speech API once a DTMF digit is received
Quote:
then Asterisk will stop doing speech recognition and switch strictly to
DTMF in itself. Once this happens the SRE is no longer involved as it is
not the one who detects or handles the DTMF. If everything is properly
setup then DTMF tones should never reach the SRE. In the case where
you've got DTMF going inband and you're not setup to process it inband,
then it would spill over to the engine but that's the only case I can
think of.
Thanks for the explanation. So this means there is no point loading a DTMF grammar in the SRE?
I'm actually driving this via AGI. For my current DTMF-based IVR, I use "STREAM FILE" and "WAIT FOR DIGIT", which both allow me to get the digits(s) pressed. For the ASR version, I'm using "EXEC" to call SpeechBackground, but I don't think that would return the digit as a result. As the application logic is quite complex, I don't want to handle DTMF in the dialplan in the traditional Asterisk IVR manner, so it looks as though I'll have to abandon trying to allow both speech and DTMF at the user's choice, and the application will have to be in one mode or the other.
Posted: Thu Feb 22, 2007 5:30 pm Post subject: [asterisk-speech-rec] DTMF
David Brazier wrote:
Quote:
Thanks for the explanation. So this means there is no point loading a
DTMF grammar in the SRE?
Pretty much.
Quote:
I'm actually driving this via AGI. For my current DTMF-based IVR, I use
"STREAM FILE" and "WAIT FOR DIGIT", which both allow me to get the
digits(s) pressed. For the ASR version, I'm using "EXEC" to call
SpeechBackground, but I don't think that would return the digit as a
result. As the application logic is quite complex, I don't want to
handle DTMF in the dialplan in the traditional Asterisk IVR manner, so
it looks as though I'll have to abandon trying to allow both speech and
DTMF at the user's choice, and the application will have to be in one
mode or the other.
DTMF gets returned as a regular speech result from the dtmf grammar with
a score of 1000.
You could do a check on that to see if they entered DTMF or did speech.
Joshua Colp
Software Developer
Digium, Inc.
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Posted: Thu Feb 22, 2007 11:05 pm Post subject: [asterisk-speech-rec] DTMF
I understand that Lumenvox SRE supports DTMF and voice grammars, but I'm
still not clear if the Asterisk/Lumenvox interface is designed to
support passing DTMF events to Lumenvox.
David
Joshua Colp wrote:
Quote:
David Brazier wrote:
> Thanks for the explanation. So this means there is no point loading
a
Quote:
> DTMF grammar in the SRE?
Pretty much.
Joshua Colp wrote:
Quote:
DTMF gets returned as a regular speech result from the dtmf grammar
with
Quote:
a score of 1000.
You could do a check on that to see if they entered DTMF or did
speech.
Stephen Keller wrote:
Quote:
The purpose of DTMF grammars is so that once the platform (in this
case Asterisk) recognizes DTMF,
Quote:
you can get semantic interpretation from the Engine regardless of
whether the user spoke or dialed.
Quote:
I.e. you can return the same semantic interpretation to your
application regardless of whether your
Quote:
user said "One" or pressed 1. It sounds like this is what you would
want for your application -- this
Quote:
way all semantic interpretation is handled in grammars and not by your
application.
Quote:
I am not sure how to pass recognized DTMF from Asterisk to the Engine
for semantic interpretation.
Quote:
Perhaps Josh or somebody else on the list is more familiar with this?
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