t31.h File Reference

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## Macros

#define | T31_TX_BUF_LEN (4096)
#define | T31_TX_BUF_HIGH_TIDE (4096 - 1024)
#define | T31_TX_BUF_LOW_TIDE (1024)
#define | T31_MAX_HDLC_LEN 284
#define | T31_T38_MAX_HDLC_LEN 260

## Typedefs

typedef struct t31_state_s | t31_state_t
typedef int | t31_modem_control_handler_t(t31_state_t *s, void *user_data, int op, const char *num)

## Functions

void | t31_call_event (t31_state_t *s, int event)
int | t31_at_rx (t31_state_t *s, const char *t, int len)
| SPAN_DECLARE_NONSTD (int) t31_rx(t31_state_t *s
| Process a block of received T.31 modem audio samples.
int | t31_t38_send_timeout (t31_state_t *s, int samples)
void | t31_set_transmit_on_idle (t31_state_t *s, int transmit_on_idle)
| Select whether silent audio will be sent when transmit is idle.
void | t31_set_tep_mode (t31_state_t *s, int use_tep)
| Select whether TEP mode will be used.
void | t31_set_t38_config (t31_state_t *s, int without_pacing)
| Select whether T.38 data will be paced.
void | t31_set_mode (t31_state_t *s, int t38_mode)
logging_state_t * | t31_get_logging_state (t31_state_t *s)
| Get a pointer to the logging context associated with a T.31 context.
t38_core_state_t * | t31_get_t38_core_state (t31_state_t *s)
t31_state_t * | t31_init (t31_state_t *s, at_tx_handler_t *at_tx_handler, void *at_tx_user_data, t31_modem_control_handler_t *modem_control_handler, void *modem_control_user_data, t38_tx_packet_handler_t *tx_t38_packet_handler, void *tx_t38_packet_user_data)
| Initialise a T.31 context.
int | t31_release (t31_state_t *s)
| Release a T.31 context.
int | t31_free (t31_state_t *s)
| Release a T.31 context.

## Variables

int16_t | amp []
int16_t int | len
int16_t int | max_len

## Typedef Documentation

## t31_state_t

typedef struct t31_state_s t31_state_t

T.31 descriptor. This defines the working state for a single instance of a T.31 FAX modem.

## Function Documentation

## SPAN_DECLARE_NONSTD()

SPAN_DECLARE_NONSTD | ( | int |  | ) |

Process a block of received T.31 modem audio samples.

Get the next bit of data from a T.38 rate adapting non-ECM buffer context.

Get a bit of received non-ECM image data.

Get the next bit of a transmitted serial bit stream.

Generate a block of T.31 modem audio samples.

Fake processing of a missing block of received T.31 modem audio samples.

Process a block of received T.31 modem audio samples.

Parameters

  s | The T.31 modem context.
  amp | The audio sample buffer.
  len | The number of samples in the buffer.

Returns
  The number of samples unprocessed.

Fake processing of a missing block of received T.31 modem audio samples (e.g due to packet loss).

Parameters

  s | The T.31 modem context.
  len | The number of samples to fake.

Returns
  The number of samples unprocessed.

Generate a block of T.31 modem audio samples.

Parameters

  s | The T.31 modem context.
  amp | The audio sample buffer.
  max_len | The number of samples to be generated.

Returns
  The number of samples actually generated.

## t31_free()

int t31_free | ( | t31_state_t * | s | ) |

Release a T.31 context.

Free a T.31 context.

Parameters

  s | The T.31 context.

Returns
  0 for OK

References t31_release().

## t31_get_logging_state()

logging_state_t * t31_get_logging_state | ( | t31_state_t * | s | ) |

Get a pointer to the logging context associated with a T.31 context.

Get a pointer to the logging context associated with a T.31 context.

Parameters

  s | The T.31 context.

Returns
  A pointer to the logging context, or NULL.

References t31_state_s::logging.

## t31_init()

t31_state_t * t31_init | ( | t31_state_t * | s,
|  | at_tx_handler_t * | at_tx_handler,
|  | void * | at_tx_user_data,
|  | t31_modem_control_handler_t * | modem_control_handler,
|  | void * | modem_control_user_data,
|  | t38_tx_packet_handler_t * | tx_t38_packet_handler,
|  | void * | tx_t38_packet_user_data )

Initialise a T.31 context.

Initialise a T.31 context. This must be called before the first use of the context, to initialise its contents.

Parameters

  s | The T.31 context.
  at_tx_handler | A callback routine to handle AT interpreter channel output.
  at_tx_user_data | An opaque pointer passed in called to at_tx_handler.
  modem_control_handler | A callback routine to handle control of the modem (off-hook, etc).
  modem_control_user_data | An opaque pointer passed in called to modem_control_handler.
  tx_t38_packet_handler | ???
  tx_t38_packet_user_data | ???

Returns
  A pointer to the T.31 context.

References at_init(), t31_state_s::call_samples, DEFAULT_DTE_TIMEOUT, at_state_s::dte_inactivity_timeout, t31_audio_front_end_state_t::last_sample, t31_state_s::logging, t31_state_s::modem, MODEM_CONNECT_TONES_ANSAM_PR, power_meter_init(), power_meter_level_dbm0(), queue_init(), QUEUE_READ_ATOMIC, QUEUE_WRITE_ATOMIC, t31_audio_front_end_state_t::rx_power, at_state_s::rx_signal_present, at_state_s::rx_trained, t31_state_s::silence_awaited, t31_audio_front_end_state_t::silence_heard, t31_audio_front_end_state_t::silence_threshold_power, t31_set_t38_config(), t31_state_s::t38_mode, and v8_init().

## t31_release()

int t31_release | ( | t31_state_t * | s | ) |

Release a T.31 context.

Release a T.31 context.

Parameters

  s | The T.31 context.

Returns
  0 for OK

Referenced by t31_free().

## t31_set_t38_config()

void t31_set_t38_config | ( | t31_state_t * | s,
|  | int | without_pacing )

Select whether T.38 data will be paced.

Select whether T.38 data will be paced as it is transmitted.

Parameters

  s | The T.31 modem context.
  without_pacing | TRUE if data is to be sent as fast as possible. FALSE if it is to be paced.

References DATA_END_TX_COUNT, DATA_TX_COUNT, INDICATOR_TX_COUNT, MS_PER_TX_CHUNK, t31_t38_front_end_state_t::ms_per_tx_chunk, t31_t38_front_end_state_t::t38, T38_PACKET_CATEGORY_CONTROL_DATA, T38_PACKET_CATEGORY_CONTROL_DATA_END, T38_PACKET_CATEGORY_IMAGE_DATA, T38_PACKET_CATEGORY_IMAGE_DATA_END, T38_PACKET_CATEGORY_INDICATOR, and t38_set_redundancy_control().

Referenced by t31_init().

## t31_set_tep_mode()

void t31_set_tep_mode | ( | t31_state_t * | s,
|  | int | use_tep )

Select whether TEP mode will be used.

Select whether TEP mode will be used (or time allowed for it (when transmitting).

Parameters

  s | The T.31 modem context.
  use_tep | TRUE if TEP is to be ised.

References fax_modems_state_s::use_tep.

## t31_set_transmit_on_idle()

void t31_set_transmit_on_idle | ( | t31_state_t * | s,
|  | int | transmit_on_idle )

Select whether silent audio will be sent when transmit is idle.

Select whether silent audio will be sent when transmit is idle.

Parameters

  s | The T.31 modem context.
  transmit_on_idle | TRUE if silent audio should be output when the transmitter is idle. FALSE to transmit zero length audio when the transmitter is idle. The default behaviour is FALSE.

References fax_modems_state_s::transmit_on_idle.