Browse Prior Art Database

Visual notification of a stream change in an IP call. Disclosure Number: IPCOM000028411D
Original Publication Date: 2004-May-14
Included in the Prior Art Database: 2004-May-14
Document File: 1 page(s) / 14K

Publishing Venue



This invention presents a method that allows a multi-modal IP based IVR system to provide the user with a visual cue when the operator joins the call.

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Visual notification of a stream change in an IP call.

This invention solves the problem described above by introducing a new payload type into the VoIP audio stream. A special "stream switch" packet will be inserted in between the transition of the "on hold" audio stream and the new "operator's speech" stream which is about to take over. On the client side, the stream handler will propagate that message up to the multi-modal application which can then provide a visual cue to the user. On the IVR side there will be a lower level streaming engine that accepts audio prompts from the system, packetizes them, and transmits them to the multi-modal client. The low level streaming engine will provide API's to accept audio and will also provide an API that indicate a stream switch. Here is a flowchart that shows how the IVR will interact with the audio layer.


Audio Layer

Send prom pt


W ait for response


Transer to operator

Send audio

  IP Network

On the client side the stream handler keys off of the "stream switch" payload type and propagates that information up to the multi-modal client. The multi-modal client will put a visual cue on the screen to alert the user that the operator has joined the call.



Send request for operator

Send stream change

Play m usic

 Wait for operator to join call


Operator joins call


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