function enables and disables the unbuffered detection of digits received on
the call. Each time a digit of the specified digit mode is detected, a message
is sent to the application indicating which digit has been detected.
| HCALL hCall,
| DWORD dwDigitModes
A handle to the call on which digits are to be detected. The call state of hCall
can be any state except idle
The digit mode or modes that are to be monitored. If dwDigitModes
is zero, digit monitoring is canceled. This parameter can have multiple flags
set, and uses the following LINEDIGITMODE_ constants:
Detect digits as audible clicks that are the result of rotary pulse sequences.
Valid digits for pulse are '0' through '9'.
Detect digits as DTMF tones. Valid digits for DTMF are '0' through '9', 'A',
'B', 'C', 'D', '*', and '#'.
Detect and provide application notification of DTMF down edges. Valid digits
for DTMF are '0' through '9', 'A', 'B', 'C', 'D', '*', and '#'.
Returns zero if the request is successful or a negative error number if an
error has occurred. Possible return values are:
LINEERR_INVALCALLHANDLE, LINEERR_OPERATIONUNAVAIL, LINEERR_INVALCALLSTATE,
LINEERR_OPERATIONFAILED, LINEERR_INVALDIGITMODE, LINEERR_RESOURCEUNAVAIL,
This function is considered successful if digit monitoring has been correctly
initiated; not when digit monitoring has terminated. Digit monitoring remains
in effect until it is explicitly disabled by calling lineMonitorDigits
set to zero, until the call transitions to idle, or when the application
deallocates its call handle for the call. Although this function can be invoked in
any call state, digits are usually detected only while the call is in the connected
Each time a digit is detected, a LINE_MONITORDIGITS message is sent to the
application passing the detected digit as a parameter.
An application can use lineMonitorDigits
to enable or disable unbuffered digit detection. It can use lineGatherDigits
for buffered digit detection. After buffered digit gathering is complete, a
LINE_GATHERDIGITS message is sent to the application. Both buffered and
unbuffered digit detection can be enabled on the same call simultaneously.
Monitoring of digits on a conference call applies only to the hConfCall
, not to the individual participating calls.
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