Voice API Programming Guide — June 2005 61
Call Progress Analysis
•Determining the Outcome of a Call
•Obtaining Additional Call Outcome Information
7.10.1 Overview of Steps to Initiate Call Progress AnalysisPerform the following procedure to initiate an outbound call with call progress analysis:
1. Set up the call analysis parameter structure (DX_CAP), which contains parameters to control
the operation of call progress analysis, such as frequency detection, cadence detection, loop
current, positive voice detection, and positive answering machine detection.
2. On Springware boards, enable call progress analysis on a specified channel using
dx_initcallp(). Modify tone definitions as appropriate.
3. Call dx_dial( ) to start an outbound call.
4. Use the ATDX_CPTERM( ) extended attribute function to determine the outcome of the call.
5. Obtain additional termination, frequency, or cadence information (such as the length of the
salutation) as desired using extended attribute functions.
Each of these steps is described in more detail next. For a full description of the functions and data
structures described in this chapter, see the Voice API Library Reference.
7.10.2 Setting Up Call Progress Analysis Features in DX_CAPThe call progress analysis parameters structure, DX_CAP, is used by dx_dial(). It contains
parameters to control the operation of call progress analysis features, such as frequency detection,
positive voice detection (PVD), and positive answering machine detection (PAMD).
To customize the parameters for your environment, you must set up the call progress analysis
parameter structure before calling a dial function.
To set up the DX_CAP structure for call progress analysis:
1. Execute the dx_clrcap( ) function to clear the DX_CAP and initialize the parameters to 0. The
value 0 indicates that the default value will be used for that particular parameter. dx_dial() can
also be set to run with default call progress analysis parameter values, by specifying a NULL
pointer to the DX_CAP structure.
2. Set a DX_CAP parameter to another value if you do not want to use the default value. The
ca_intflg field (intercept mode flag) of DX_CAP enables and disables the following call
progress analysis components: SIT frequency detection, positive voice detection (PVD), and
positive answering machine detection (PAMD). Use one of the following values for the
ca_intflg field:
•DX_OPTDIS. Disables Special Information Tone (SIT) frequency detection, PAMD, and
PVD.
•DX_OPTNOCON. Enables SIT frequency detection and returns an “intercept”
immediately after detecting a valid frequency.
•DX_PVDENABLE. Enables PVD and fax tone detection.
•DX_PVDOPTNOCON. Enables PVD, DX_OPTNOCON, and fax tone detection.