Voice API Programming Guide — June 2005 47
Call Progress Analysis
Table4 provides information on call progress analysis scenarios supported with the dx_dial( )
function. This method is available regardless of the protocol being used; however, some restrictions
apply when using DM3 CAS protocols. The restrictions are due to the fact that the voice capability
is shared between the network device and the voice channel during the call setup time. In particular,
to invoke dx_dial() under channel associated signaling (CAS), your application must wait for the
connected event.
Note: The information in this table also applies to DM3 analog products, which are considered to use
CAS protocols.
7.4.2 Overview of Steps to Initiate Call Progress Analysis
Review the information in Section7.4.1, “Call Progress Analysis Rules on DM3 Boards”, on
page 46. If you choose to use the voice API for call progress analysis on DM3 boards, perform 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 positive voice detection and positive answering
machine detection.
2. Call dx_dial( ) to start call progress analysis during the desired phase of the call.
3. Use the ATDX_CPTERM( ) extended attribute function to determine the outcome of the call.
4. Obtain additional termination information 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.
Table4. Call Progress Analysis Support with dx_dial( )
CPA Feature
dx_dial()
support on
DM3
Comments
Busy Yes analog/CAS protocols: not supported
No ringback Yes analog/CAS protocols: not supported
SIT frequency detection Yes analog/CAS protocols: not supported
No answer Yes analog/CAS protocols: not supported
Cadence break Yes analog/CAS protocols: not supported
Loop current detection No
Dial tone detection No
Fax tone detection Yes analog/CAS protocols: wait for GlobalCall
GCEV_CONNECTED event
Positive Voice Detection (PVD) Yes analog/CAS protocols: wait for GlobalCall
GCEV_CONNECTED event
Positive Answering Machine
Detection (PAMD)
Yes analog/CAS protocols: wait for GlobalCall
GCEV_CONNECTED event