Voice API Programming Guide — June 2005 85
Call Progress Analysis
Cadence detection will measure the length of the salutation when the ca_hedge (hello edge)
parameter is set to 2 (the default).
ca_hedge
Hello Edge: the point at which a connect will be returned to the application, either the rising
edge (immediately when a connect is detected) or the falling edge (after the end of the
salutation).
1 = rising edge. 2 = falling edge. Default: 2 (connect returned on falling edge of salutation).
Try changing this if the called party has to say “Hello” twice to trigger the answer event.
Because a greeting might consist of several words, call progress analysis waits for a specified
period of silence before assuming the salutation is finished. The ca_ansrdgl (answer deglitcher)
parameter determines when the end of the salutation occurs. This parameter specifies the maximum
amount of silence allowed in a salutation before it is determined to be the end of the salutation. To
use ca_ansrdgl, set it to approximately 50 (in 10 msec units).
ca_ansrdgl
Answer Deglitcher: the maximum silence period (in 10 msec units) allowed between words in
a salutation. This parameter should be enabled only when you are interested in measuring the
length of the salutation. Default: -1 (disabled).
The ca_maxansr (maximum answer) parameter determines the maximum allowable answer size
before returning a connect.
ca_maxansr
Maximum Answer: the maximum allowable length of ansrsize. When ansrsize exceeds
ca_maxansr, a connect is returned to the application. Default: 1000 (in 10 msec units), or 10
seconds.
Figure 13 shows how the ca_ansrdgl parameter works.
Figure 13. Cadence Detection Salutation Processing
When ca_hedge = 2, cadence detection waits for the end of the salutation before returning a
connect. The end of the salutation occurs when the salutation contains a period of silence that
exceeds ca_ansrdgl or the total length of the salutation exceeds ca_maxansr. When the connect
event is returned, the length of the salutation can be retrieved using the ATDX_ANSRSIZ()
function.
CA_ANSRDGL
Connect Event
Returned Here
nonsilence
silence
Connection
Detected Salutation
"Good Afternoon,""Intel Corporation"
CA_ANSRDGL