LINE_MONITORMEDIA
The
LINE_MONITORMEDIA message is sent when a change in the call's media mode is
detected. The sending of this message is controlled with the lineMonitorMedia function.
LINE_MONITORMEDIA
dwDevice = (DWORD) hCall;
dwCallbackInstance = (DWORD) hCallback;
dwParam1 =
(DWORD) MediaMode;
dwParam2 =
(DWORD) 0;
dwParam3 =
(DWORD) 0;
Parameters
dwDevice
A handle to
the call.
dwCallbackInstance
The callback
instance supplied when opening the line.
dwParam1
The new media
mode. This parameter must be one and only one of the following LINEMEDIAMODE_
constants:
LINEMEDIAMODE_INTERACTIVEVOICE
The presence
of voice energy has been detected and the call is treated as an interactive
call with humans on both ends.
LINEMEDIAMODE_AUTOMATEDVOICE
The presence
of voice energy has been detected and the call is locally handled by an
automated application.
LINEMEDIAMODE_DATAMODEM
A data modem
session has been detected.
LINEMEDIAMODE_G3FAX
A group 3 fax
has been detected.
LINEMEDIAMODE_TDD
A TDD
(Telephony Devices for the Deaf) session has been detected.
LINEMEDIAMODE_G4FAX
A group 4 fax
has been detected.
LINEMEDIAMODE_DIGITALDATA
Digital data
has been detected.
LINEMEDIAMODE_TELETEX
A teletex
session has been detected. Teletex is one of the telematic services.
LINEMEDIAMODE_VIDEOTEX
A videotex
session has been detected. Videotex is one the telematic services.
LINEMEDIAMODE_TELEX
A telex
session has been detected. Telex is one the telematic services.
LINEMEDIAMODE_MIXED
A mixed session
has been detected. Mixed is one the telematic services.
LINEMEDIAMODE_ADSI
An ADSI
(Analog Display Services Interface) session has been detected.
LINEMEDIAMODE_VOICEVIEW
The media
mode of the call is VoiceView.
dwParam2
Unused.
dwParam3
The
"tick count" (number of milliseconds since Windows started) at which
the specified media was detected. For API versions prior to 0x00020000, this
parameter is unused.
Return Values
No return
value.
Remarks
The
LINE_MONITORMEDIA message is sent to the application that has enabled media
monitoring for the media mode detected.
Because this timestamp
may have been generated on a computer other than the one on which the
application is executing, it is useful only for comparison to other similarly
timestamped messages generated on the same line device (LINE_GATHERDIGITS,
LINE_GENERATE, LINE_MONITORDIGITS, LINE_MONITORTONE), in order to determine
their relative timing (separation between events). The tick count can
"wrap around" after approximately 49.7 days; applications must take
this into account when performing calculations.
If the
service provider does not generate the timestamp (for example, if it was
created using an earlier version of TAPI), then TAPI will provide a timestamp
at the point closest to the service provider generating the event so that the
synthesized timestamp is as accurate as possible.
See Also