Voice API Programming Guide — June 2005 169
14
14.Global Dial Pulse Detection
Global dial pulse detection (global DPD) is a signaling component of the voice library. The
following topics provide more information on global DPD:
•Key Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169
•Global DPD Parameters. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170
•Enabling Global DPD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170
•Global DPD Programming Considerations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171
•Retrieving Digits from the Digit Buffer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171
•Retrieving Digits as Events . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172
•Dial Pulse Detection Digit Type Reporting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172
•Defines for Digit Type Reporting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172
•Global DPD Programming Procedure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173
•Global DPD Example Code. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173
14.1 Key Features
Global dial pulse detection is not supported on DM3 boards.
Dial Pulse Detection (DPD) allows applications to detect dial pulses from rotary or pulse phones by
detecting the audible clicks produced when a number is dialed, and to use these clicks as if they
were DTMF digits. Intel global dial pulse detection, called global DPD, is a software-based dial
pulse detection method that can use country-customized parameters for extremely accurate
performance.
Global DPD provides the following features and benefits:
•The global DPD algorithm is adaptive and can train on any DPD digit it encounters, with the
greatest accuracy produced from training on a digit that has 5 or more pulses. Global DPD
does not require a leading “0” to train the global DPD algorithm.
•Global DPD can be performed simultaneously with DTMF detection. The application can
determine whether the digit detected is a DTMF or DPD digit.
•Global DPD can be performed simultaneously with Global Tone Detection (GTD). For
example, the application can use GTD to monitor for dial tone or busy tones simultaneously
with DPD.
•Global DPD supports pulse-digit cut-through during a voice playback, with the correct digit
returned in the digit buffer. Global DPD uses echo cancellation, which provides more accurate
reporting of digits during voice playback.