spandsp 3.0.0
t31.c File Reference
#include <inttypes.h>
#include <stdlib.h>
#include <stdio.h>
#include <fcntl.h>
#include <time.h>
#include <memory.h>
#include <string.h>
#include <ctype.h>
#include "spandsp/stdbool.h"
#include "floating_fudge.h"
#include <assert.h>
#include <tiffio.h>
#include "spandsp/telephony.h"
#include "spandsp/alloc.h"
#include "spandsp/logging.h"
#include "spandsp/bit_operations.h"
#include "spandsp/bitstream.h"
#include "spandsp/dc_restore.h"
#include "spandsp/queue.h"
#include "spandsp/power_meter.h"
#include "spandsp/complex.h"
#include "spandsp/tone_detect.h"
#include "spandsp/tone_generate.h"
#include "spandsp/modem_echo.h"
#include "spandsp/async.h"
#include "spandsp/crc.h"
#include "spandsp/hdlc.h"
#include "spandsp/vector_int.h"
#include "spandsp/silence_gen.h"
#include "spandsp/super_tone_rx.h"
#include "spandsp/fsk.h"
#include "spandsp/modem_connect_tones.h"
#include "spandsp/godard.h"
#include "spandsp/v8.h"
#include "spandsp/v29tx.h"
#include "spandsp/v29rx.h"
#include "spandsp/v27ter_tx.h"
#include "spandsp/v27ter_rx.h"
#include "spandsp/v17tx.h"
#include "spandsp/v17rx.h"
#include "spandsp/timezone.h"
#include "spandsp/t4_rx.h"
#include "spandsp/t4_tx.h"
#include "spandsp/t30.h"
#include "spandsp/t30_logging.h"
#include "spandsp/t38_core.h"
#include "spandsp/at_interpreter.h"
#include "spandsp/fax_modems.h"
#include "spandsp/t31.h"
#include "spandsp/t30_fcf.h"
#include "spandsp/private/logging.h"
#include "spandsp/private/bitstream.h"
#include "spandsp/private/modem_echo.h"
#include "spandsp/private/t38_core.h"
#include "spandsp/private/silence_gen.h"
#include "spandsp/private/power_meter.h"
#include "spandsp/private/fsk.h"
#include "spandsp/private/modem_connect_tones.h"
#include "spandsp/private/v8.h"
#include "spandsp/private/godard.h"
#include "spandsp/private/v17tx.h"
#include "spandsp/private/v17rx.h"
#include "spandsp/private/v27ter_tx.h"
#include "spandsp/private/v27ter_rx.h"
#include "spandsp/private/v29tx.h"
#include "spandsp/private/v29rx.h"
#include "spandsp/private/hdlc.h"
#include "spandsp/private/fax_modems.h"
#include "spandsp/private/at_interpreter.h"
#include "spandsp/private/t31.h"

Macros

#define INDICATOR_TX_COUNT   3
 
#define DATA_TX_COUNT   1
 
#define DATA_END_TX_COUNT   3
 
#define DEFAULT_DTE_TIMEOUT   5
 
#define MAX_OCTETS_PER_UNPACED_CHUNK   300
 
#define MID_RX_TIMEOUT   15000
 
#define HDLC_FRAMING_OK_THRESHOLD   5
 

Typedefs

typedef const char *(* at_cmd_service_t) (t31_state_t *s, const char *cmd)
 

Enumerations

enum  { ETX = 0x03 , DLE = 0x10 , SUB = 0x1A }
 
enum  {
  DISBIT1 = 0x01 , DISBIT2 = 0x02 , DISBIT3 = 0x04 , DISBIT4 = 0x08 ,
  DISBIT5 = 0x10 , DISBIT6 = 0x20 , DISBIT7 = 0x40 , DISBIT8 = 0x80
}
 
enum  {
  T38_TIMED_STEP_NONE = 0 , T38_TIMED_STEP_NON_ECM_MODEM = 0x10 , T38_TIMED_STEP_NON_ECM_MODEM_2 = 0x11 , T38_TIMED_STEP_NON_ECM_MODEM_3 = 0x12 ,
  T38_TIMED_STEP_NON_ECM_MODEM_4 = 0x13 , T38_TIMED_STEP_NON_ECM_MODEM_5 = 0x14 , T38_TIMED_STEP_HDLC_MODEM = 0x20 , T38_TIMED_STEP_HDLC_MODEM_2 = 0x21 ,
  T38_TIMED_STEP_HDLC_MODEM_3 = 0x22 , T38_TIMED_STEP_HDLC_MODEM_4 = 0x23 , T38_TIMED_STEP_HDLC_MODEM_5 = 0x24 , T38_TIMED_STEP_CED = 0x30 ,
  T38_TIMED_STEP_CED_2 = 0x31 , T38_TIMED_STEP_CED_3 = 0x32 , T38_TIMED_STEP_CNG = 0x40 , T38_TIMED_STEP_CNG_2 = 0x41 ,
  T38_TIMED_STEP_PAUSE = 0x50 , T38_TIMED_STEP_NO_SIGNAL = 0x60
}
 

Functions

int t31_t38_send_timeout (t31_state_t *s, int samples)
 
void t31_call_event (t31_state_t *s, int event)
 
int t31_at_rx_free_space (t31_state_t *s)
 Return the amount of free space in the AT COMMAND BUFFER.
 
int t31_at_rx (t31_state_t *s, const char *t, int len)
 
int t31_rx (t31_state_t *s, int16_t amp[], int len)
 Process a block of received T.31 modem audio samples.
 
int t31_rx_fillin (t31_state_t *s, int len)
 Fake processing of a missing block of received T.31 modem audio samples.
 
int t31_tx (t31_state_t *s, int16_t amp[], int max_len)
 Generate a block of T.31 modem audio samples.
 
void t31_set_transmit_on_idle (t31_state_t *s, bool transmit_on_idle)
 Select whether silent audio will be sent when transmit is idle.
 
void t31_set_tep_mode (t31_state_t *s, bool use_tep)
 Select whether TEP mode will be used.
 
void t31_set_t38_config (t31_state_t *s, bool without_pacing)
 Select whether T.38 data will be paced.
 
void t31_set_mode (t31_state_t *s, bool t38_mode)
 Set audio or T.38 mode.
 
logging_state_tt31_get_logging_state (t31_state_t *s)
 Get a pointer to the logging context associated with a T.31 context.
 
at_state_tt31_get_at_state (t31_state_t *s)
 Get a pointer to the AT interpreter context associated with a T.31 context.
 
t38_core_state_tt31_get_t38_core_state (t31_state_t *s)
 Get a pointer to the T.38 core context associated with a T.31 context.
 
t31_state_tt31_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.
 

Macro Definition Documentation

◆ DATA_END_TX_COUNT

#define DATA_END_TX_COUNT   3

The number of transmissions of terminating data IFP packets

Referenced by t31_set_t38_config(), and t38_terminal_set_config().

◆ DATA_TX_COUNT

#define DATA_TX_COUNT   1

The number of transmissions of data IFP packets

Referenced by t31_set_t38_config(), and t38_terminal_set_config().

◆ DEFAULT_DTE_TIMEOUT

#define DEFAULT_DTE_TIMEOUT   5

The default DTE timeout, in seconds

Referenced by t31_init().

◆ INDICATOR_TX_COUNT

#define INDICATOR_TX_COUNT   3

The number of transmissions of indicator IFP packets

Referenced by t31_set_t38_config(), and t38_terminal_set_config().

Function Documentation

◆ t31_at_rx_free_space()

int t31_at_rx_free_space ( t31_state_t * s)

Return the amount of free space in the AT COMMAND BUFFER.

Return the amount of free space in the AT COMMAND BUFFER.

Parameters
sThe T.31 modem context.
Returns
The number of bytes of free space.

References t31_state_s::in_bytes, t31_state_s::non_ecm_tx, and t31_state_s::out_bytes.

◆ t31_free()

int t31_free ( t31_state_t * s)

Release a T.31 context.

Free a T.31 context.

Parameters
sThe T.31 context.
Returns
0 for OK

References t31_release().

◆ t31_get_at_state()

at_state_t * t31_get_at_state ( t31_state_t * s)

Get a pointer to the AT interpreter context associated with a T.31 context.

Get a pointer to the AT interpreter context associated with a T.31 context.

Parameters
sThe T.31 context.
Returns
A pointer to the AT interpreter context, or NULL.

◆ 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
sThe T.31 context.
Returns
A pointer to the logging context, or NULL.

References t31_state_s::logging.

◆ t31_get_t38_core_state()

t38_core_state_t * t31_get_t38_core_state ( t31_state_t * s)

Get a pointer to the T.38 core context associated with a T.31 context.

Get a pointer to the T.38 core context associated with a T.31 context.

Parameters
sThe T.31 context.
Returns
A pointer to the T.38 core context, or NULL.

References t31_t38_front_end_state_t::t38.

◆ 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
sThe T.31 context.
at_tx_handlerA callback routine to handle AT interpreter channel output.
at_tx_user_dataAn opaque pointer passed in called to at_tx_handler.
modem_control_handlerA callback routine to handle control of the modem (off-hook, etc).
modem_control_user_dataAn 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_free(), 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, fax_modems_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, span_dummy_rx(), span_dummy_rx_fillin(), 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
sThe T.31 context.
Returns
0 for OK

References queue_release(), and v8_release().

Referenced by t31_free().

◆ t31_rx()

int t31_rx ( t31_state_t * s,
int16_t amp[],
int len )

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

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

Parameters
sThe T.31 modem context.
ampThe audio sample buffer.
lenThe number of samples in the buffer.
Returns
The number of samples unprocessed.

References t31_state_s::call_samples, t31_audio_front_end_state_t::last_sample, power_meter_update(), fax_modems_state_s::rx_handler, t31_audio_front_end_state_t::rx_power, t31_audio_front_end_state_t::silence_heard, and t31_audio_front_end_state_t::silence_threshold_power.

◆ t31_rx_fillin()

int t31_rx_fillin ( t31_state_t * s,
int len )

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

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

Parameters
sThe T.31 modem context.
lenThe number of samples to fake.
Returns
The number of samples unprocessed.

References t31_state_s::call_samples, and fax_modems_state_s::rx_fillin_handler.

◆ t31_set_mode()

void t31_set_mode ( t31_state_t * s,
bool t38_mode )

Set audio or T.38 mode.

Set audio or T.38 mode.

Parameters
sThe T.31 modem context.
t38_modeTrue for T.38 mode operation. False for audio mode operation.

References t31_state_s::logging, span_log(), and t31_state_s::t38_mode.

◆ t31_set_t38_config()

void t31_set_t38_config ( t31_state_t * s,
bool without_pacing )

Select whether T.38 data will be paced.

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

Parameters
sThe T.31 modem context.
without_pacingTrue 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, 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, t38_set_redundancy_control(), and t38_set_tx_packet_interval().

Referenced by t31_init().

◆ t31_set_tep_mode()

void t31_set_tep_mode ( t31_state_t * s,
bool use_tep )

Select whether TEP mode will be used.

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

Parameters
sThe T.31 modem context.
use_tepTrue if TEP is to be used.

References fax_modems_state_s::use_tep.

◆ t31_set_transmit_on_idle()

void t31_set_transmit_on_idle ( t31_state_t * s,
bool 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
sThe T.31 modem context.
transmit_on_idleTrue 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.

◆ t31_tx()

int t31_tx ( t31_state_t * s,
int16_t amp[],
int max_len )

Generate a block of T.31 modem audio samples.

Generate a block of T.31 modem audio samples.

Parameters
sThe T.31 modem context.
ampThe audio sample buffer.
max_lenThe number of samples to be generated.
Returns
The number of samples actually generated.

References fax_modems_state_s::transmit_on_idle, and fax_modems_state_s::tx_handler.