The CloseTxIvrChannel API procedure closes a previously opened phone line IVR channel. After calling this procedure, the IVR handle value is invalid.

Call the GetNumIvrTxBuffers API procedure to determine how many phone line transmit buffers are available for use.

The GetTxIvrSampleBlockSize API procedure is used by application software to determine the transmit sample block size the phone line requires.

The OpenTxIvrChannel API procedure allows application software to open a transmit IVR channel to the specified phone line. By opening a transmit IVR channel to the phone line, the application can stream sampled audio data directly to the phone line.

The SetTxIvrBufferEvent API procedure allows the telephony engine to signal the application software when transmit buffers are available.

The SetTxIvrDataType API procedure allows the user application to specify the format and rate of the data it will send directly to the phone line.

The StopIvrTransmit API procedure should be called by application software to immediately stop the streaming of data to the phone line. Also, calling this procedure will force the phone line to dump all queued up transmit audio data it may have.

The TransmitInCallIvrData API procedure should be called by application software to transmit data out the phone line when the call is active (i.e. When the phone line is in the SipInCall state).

The TransmitOnHoldIvrData API procedure should be called by application software to transmit data out the phone line when the call has been placed on hold (i.e. your software put the call on hold).

Call the WaitForIvrTransmitComplete API procedure before closing the IVR transmit channel of the phone line. Doing so will ensure that all queued audio sample data gets transmitted out the line before it gets closed.