4.1.0.14 LINE_MONITORTONE

This message is sent whenever a monitored tone is detected. The sending of this message is controlled via the TSPI_lineMonitorTone function. A single tone detection may result in the Service Provider sending this message several times in the case where the detected tone matches several tone descriptions in several different tone lists. A tone may "match" several non-identical tone descriptions depending on how close they are to one another and the discrimination limits achieved by the Service Provider. Multiple matches may occur within the same or different tone lists.

Sent to

LINEEVENT


Parameters

HTAPILINE htLine
Specifies the TAPI DLL's opaque object handle to the line device.

HTAPICALL htCall
Specifies the TAPI DLL's opaque object handle to the call device.

DWORD dwMsg
The value LINE_MONITORTONE

DWORD dwParam1
Specifies the app specific field dwAppSpecific of the LINEMONITORTONE structure for the tone that was detected.

DWORD dwParam2
Specifies the dwToneListID of the tone list containing a matching tone description.

DWORD dwParam3
Unused.

Comments

This message is sent once for each tone it matches in each tone list. Since there can be multiple matches both within a single tone list and across multiple tone lists, a single tone detection may result in several messages indicating the same dwToneListID and several messages with a differing dwToneListID.

Comparison

The dwParam2 field in the corresponding message at the TAPI level is unused. The TAPI DLL forwards all tone monitoring requests from all applications to the Service Provider to be handled concurrently. It assigns a unique dwToneListID to each tone list and uses the dwToneListID added to dwParam2 at the TAPI level to discriminate the resulting messages.

See Also

Functions: TSPI_lineMonitorTones
Data Types: LINEMONITORTONE