The SetRfc2833DtmfDecoderEnableState API procedure is used to enable and disable RFC2833 DTMF decoding for the specified phone line. Application software can call this procedure any time.
RFC2833 DTMF must be initialized before initiating or receiving calls on the phone line. This is because RFC2833 DTMF requires specific SDP "telephone-event" media descriptors to be present in outgoing SIP INVITE requests and in incoming "200 OK" responses.

Namespace:  LanScape
Assembly:  LMEVoipManaged (in LMEVoipManaged.dll) Version: 6.0.5226.26700


public VoipMediaEngine..::.TELEPHONY_RETURN_VALUE SetRfc2833DtmfDecoderEnableState(
	int PhoneLine,
	bool EnableState
Visual Basic (Declaration)
Public Function SetRfc2833DtmfDecoderEnableState ( _
	PhoneLine As Integer, _
	EnableState As Boolean _
Visual C++
VoipMediaEngine..::.TELEPHONY_RETURN_VALUE SetRfc2833DtmfDecoderEnableState(
	int PhoneLine, 
	bool EnableState
public VoipMediaEngine..::.TELEPHONY_RETURN_VALUE SetRfc2833DtmfDecoderEnableState(
	int PhoneLine,
	boolean EnableState


Type: System..::.Int32
The zero based phone line to access.
Type: System..::.Boolean
Specifies the enable state of RFC2833 DTMF detection for the phone line.

Return Value

If the function succeeds, the return value will be SipSuccess.

If the function fails, the return value will be one of the following values as specified by the VoipMediaEngine..::.TELEPHONY_RETURN_VALUE data type.

Return ValueDescription
This value is returned by telephony API procedures to indicate general API failure. This error value is used as a "catch all error". If you receive this error, check to make sure that all parameters specified in the API procedure call are correct. Particularly, verify that pointers to memory regions are valid. This error return value is only used if a mapping to another specific error value does not exist.

(API return value)

Application software specified an invalid telephony handle in one of the API procedures. This usually indicates memory corruption on the part of application software.

(API return value)

Application software called a telephony API procedure and specified an invalid phone line. Phone lines are numbered starting from zero. This error is most commonly returned when attempting to access phone lines in excess of the max number of lines supported by the telephony engine.

(API return value)

Internal media engine in-band and RFC2833 DTMF support has not been enabled. See the DtmfEnabled startup parameter in the VoipMediaEngine..::.START_SIP_TELEPHONY_PARAMS structure for additional information.

(API return value)

The application tried to destroy an in-band DTMF decoder for a phone line using the UnInitializeInBandDtmfDecoder(Int32) API procedure and the DTMF decoder did not exists.

(API return value)

The telephony engine attempted to allocate system memory but the allocation failed. Make sure the host system has enough virtual memory. Increasing the amount of virtual memory can remove these errors, however if critical telephony engine code has been swapped out to disk and is not resident in physical memory, you may experience degraded audio/video performance. If you want to remove this error and obtain the best possible audio/video performance, make sure the host system has enough physical memory. To resolve this error, you may also want to consider disabling certain features of the media engine such as conference calling. You can also reduce memory requirements if you reduce the maximum signal length of internal media engine signal paths by specifying a smaller number for the MaxMixerLinebuffers member of the VoipMediaEngine..::.START_SIP_TELEPHONY_PARAMS class that is passed to the StartSipTelephony(VoipMediaEngine..::.START_SIP_TELEPHONY_PARAMS) and ReStartSipTelephony(VoipMediaEngine..::.START_SIP_TELEPHONY_PARAMS) API procedures.




See Also