dtmf.h File Reference

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Classes

struct  dtmf_tx_state_t
struct  dtmf_rx_state_t

Defines

#define _SPANDSP_DTMF_H_
#define MAX_DTMF_DIGITS   128

Typedefs

typedef void(*) dtmf_rx_callback_t (void *user_data, const char *digits, int len)

Functions

int dtmf_tx (dtmf_tx_state_t *s, int16_t amp[], int max_samples)
 Generate a buffer of DTMF tones.
size_t dtmf_tx_put (dtmf_tx_state_t *s, const char *digits)
 Put a string of digits in a DTMF generator's input buffer.
dtmf_tx_state_tdtmf_tx_init (dtmf_tx_state_t *s)
 Initialise a DTMF tone generator context.
void dtmf_rx_set_realtime_callback (dtmf_rx_state_t *s, tone_report_func_t callback, void *user_data)
 Set a realtime callback for a DTMF receiver context.
void dtmf_rx_parms (dtmf_rx_state_t *s, int filter_dialtone, int twist, int reverse_twist)
 Adjust a DTMF receiver context.
int dtmf_rx (dtmf_rx_state_t *s, const int16_t amp[], int samples)
 Process a block of received DTMF audio samples.
size_t dtmf_rx_get (dtmf_rx_state_t *s, char *digits, int max)
 Get a string of digits from a DTMF receiver's output buffer.
dtmf_rx_state_tdtmf_rx_init (dtmf_rx_state_t *s, dtmf_rx_callback_t callback, void *user_data)
 Initialise a DTMF receiver context.


Detailed Description


Function Documentation

int dtmf_rx ( dtmf_rx_state_t s,
const int16_t  amp[],
int  samples 
)

Process a block of received DTMF audio samples.

Process a block of received DTMF audio samples.

Parameters:
s The DTMF receiver context.
amp The audio sample buffer.
samples The number of samples in the buffer.
Returns:
The number of samples unprocessed.

size_t dtmf_rx_get ( dtmf_rx_state_t s,
char *  digits,
int  max 
)

Get a string of digits from a DTMF receiver's output buffer.

Parameters:
s The DTMF receiver context.
digits The buffer for the received digits.
max The maximum number of digits to be returned,
Returns:
The number of digits actually returned.

dtmf_rx_state_t* dtmf_rx_init ( dtmf_rx_state_t s,
dtmf_rx_callback_t  callback,
void *  user_data 
)

Initialise a DTMF receiver context.

Parameters:
s The DTMF receiver context.
callback An optional callback routine, used to report received digits. If no callback routine is set, digits may be collected, using the dtmf_rx_get() function.
user_data An opaque pointer which is associated with the context, and supplied in callbacks.
Returns:
A pointer to the DTMF receiver context.

void dtmf_rx_parms ( dtmf_rx_state_t s,
int  filter_dialtone,
int  twist,
int  reverse_twist 
)

Adjust a DTMF receiver context.

Parameters:
s The DTMF receiver context.
filter_dialtone TRUE to enable filtering of dialtone, FALSE to disable, < 0 to leave unchanged.
twist Acceptable twist, in dB. < 0 to leave unchanged.
reverse_twist Acceptable reverse twist, in dB. < 0 to leave unchanged.

void dtmf_rx_set_realtime_callback ( dtmf_rx_state_t s,
tone_report_func_t  callback,
void *  user_data 
)

Set a realtime callback for a DTMF receiver context.

Set a optional realtime callback for a DTMF receiver context. This function is called immediately a confirmed state change occurs in the received DTMF. It is called with the ASCII value for a DTMF tone pair, or zero to indicate no tone is being received.

Parameters:
s The DTMF receiver context.
callback Callback routine used to report the start and end of digits.
user_data An opaque pointer which is associated with the context, and supplied in callbacks.

int dtmf_tx ( dtmf_tx_state_t s,
int16_t  amp[],
int  max_samples 
)

Generate a buffer of DTMF tones.

Parameters:
s The DTMF generator context.
amp The buffer for the generated signal.
max_samples The required number of generated samples.
Returns:
The number of samples actually generated. This may be less than max_samples if the input buffer empties.

dtmf_tx_state_t* dtmf_tx_init ( dtmf_tx_state_t s  ) 

Initialise a DTMF tone generator context.

Parameters:
s The DTMF generator context.
Returns:
A pointer to the DTMF generator context.

size_t dtmf_tx_put ( dtmf_tx_state_t s,
const char *  digits 
)

Put a string of digits in a DTMF generator's input buffer.

Parameters:
s The DTMF generator context.
digits The string of digits to be added.
Returns:
The number of digits actually added. This may be less than the length of the digit string, if the buffer fills up.


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