Created by: Koen Van Impe on 15-10-2013 07:49:47 AM Hi all,
I am a bit puzzled with the dtmf buffer behavior when a call uses multiple Call Studio applications. To set the scene: we are deploying a comprehensive CVP 9.0. The ICM script calls 2 different Call Studio apps. While the first app plays welcome with barge-in enabled, I type ahead because I know what the next menu is about (that menu being part of the second app - a form element). Barge-in is enabled on all audio groups. I would expect the menu to skip the audio and read the dtmf entered during welcome from the buffer. For some reason it doesn't. Even if the IVR is spread over 2 apps, it is the same call and I would think it uses the same buffer. Or not?
I thought I did this before, over a year ago. But I don't have access to that system anymore, so I would appreciate anyone share experience on this.
Rgds, K
Subject: RE: DTMF buffer across Call Studio apps Replied by: Janine Graves on 15-10-2013 10:10:51 AM Koen, Are you doing an App Transfer or Subdialog_Invoke? The VXML Gateway executes the Subdialog_Invoke, so it might clear the buffer before invoking or returning from the Invoked app.
But, App Transfer is invisible to the gateway, it's executed by VxmlServer - so in that case, I'd guess the gateway does pass the DTMF to the transferred-to app. BUT - I haven't tested these with CVP 9 yet. AND - (unfortunately) I've seen behavior change version to version on the gateway and it's also different if you're writing a DTMF-only application versus an app using a speech recognizer.
Distrust and verify! That's my motto :-)
Subject: RE: DTMF buffer across Call Studio apps Replied by: Paul Tindall on 15-10-2013 02:24:35 PM Before the Studio app returns to ICM there's a document served containing a dummy <object> element. This is done to allow any audio operations to complete and return to ICM synchronously. There's a <cisco-typeaheadflush> element in the block that handles call handoff failure when the dummy object element (deliberately) fails. That may well be the cause of what you're seeing particularly as the dummy object approach was introduced in a relatively recent version (possibly 8.0).
Subject: RE: DTMF buffer across Call Studio apps Replied by: Koen Van Impe on 15-10-2013 02:25:27 PM Janine,
After the first app control actually returns to ICM. After checking the results of that, a second app is called. So we are not using Application Transfer or Subdialog Invoke. I will consider these options if no solution in the current setup. But it will require some rework...
Is the use of a dtmf buffer on the gateway linked to one vxml session? Rgds, Koen
Subject: RE: DTMF buffer across Call Studio apps Replied by: Janine Graves on 15-10-2013 02:33:58 PM Returning to ICM is analogour to returning from an invoked subdialog. See Paul's reply. He knows this stuff inside out. I wonder if you could write a custom CVP_Subdialog_Return that does NOT include the cisco-typeahead-flush.
Subject: RE: DTMF buffer across Call Studio apps Replied by: Koen Van Impe on 15-10-2013 02:44:43 PM Paul,
Yes, I saw the cisco proprietary property in the vxml output, but didn't think it mattered since it's in a catch block. But you mention that the failure is deliberate. So yes, that is probably the cause. Any way to change that behavior?
Thx (again)! Koen
Subject: RE: DTMF buffer across Call Studio apps Replied by: Paul Tindall on 15-10-2013 02:48:29 PM Right, I'd definitely try a custom return and see if that makes a difference.
Subject: RE: DTMF buffer across Call Studio apps Replied by: Koen Van Impe on 15-10-2013 03:34:14 PM I'm always up for a challenge :-) But couldn't find a template for a custom return element. Could you get me started?
Never mind. Found the CiscoSubdialogReturnElement, will use that as a base.
Subject: RE: DTMF buffer across Call Studio apps Replied by: Paul Tindall on 15-10-2013 03:48:18 PM I think I have the original one that I used to prototype the dummy object approach so you can have that if you want.
Subject: RE: DTMF buffer across Call Studio apps Replied by: Koen Van Impe on 15-10-2013 03:54:35 PM That would be nice. Thank you!
Subject: RE: DTMF buffer across Call Studio apps Replied by: Paul Tindall on 15-10-2013 06:15:10 PM Koen,
This one probably needs some tweaks but it should be OK as a starting point to check out the typeahead buffer issue. It does have an exit state so just connect it to a hangup as it will never get there anyway.
Subject: RE: DTMF buffer across Call Studio apps Replied by: Koen Van Impe on 16-10-2013 02:35:06 AM Paul,
I tested with your custom return element and yes, the dtmf remains in buffer and is read in the next studio application. I does need some work though to also return FromExtVXML. Since I don't have the time (and little experience) to rewrite all that and debug it, I think I'll rewrite the Studio apps and merge it to one. Or transfer between apps within Studio.
Nevertheless, I would suggest to leave it to the application developer when he wants to flush the buffer. As Janine suggests (here) it would be nice to have a voice element that just flushes the buffer on demand. And remove the flush from the return element.
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