2.4. Modifying the Default PerfectCall Tone Definitions

PerfectCall Call Analysis makes use of Global Tone Detection (GTD) tone definitions for three different types of dial tones, two busy tones, one ringback tone, and two fax tones. The tone definitions specify the frequencies, durations and repetition counts necessary to identify each of these signals. Each signal may consist of a single tone or a dual tone.

The Voice Driver contains default definitions for each of these tones. The default definitions will allow applications to identify the tones correctly in most countries and for most switching equipment. If, however, a situation arises in which the default tone definitions are not adequate, three functions are provided to modify the standard tone definitions:

• dx_chgfreq( ) specifies frequencies and tolerances for one or both frequencies of a single frequency or dual-frequency tone.
• dx_chgdur( ) specifies the cadence (on time, off time, and acceptable deviations) for a tone.
• dx_chgrepcnt( ) specifies the repetition count required to identify a tone.

These functions only change the tone definitions, they do not alter the process of PerfectCall Call Analysis. When the dx_initcallp( ) function is invoked to activate PerfectCall Call Analysis on a particular channel, it uses the current tone definitions to initialize that channel. Multiple calls to dx_initcallp( ) may therefore use varying tone definitions, and several channels can operate simultaneously with different tone definitions.

Details on these functions may be found in the Voice Software Reference: Programmer's Guide.

Click here to contact Dialogic Customer Engineering