t38_gateway.c File Reference

#include <inttypes.h>
#include <stdlib.h>
#include <stdio.h>
#include <fcntl.h>
#include <time.h>
#include <string.h>
#include <assert.h>
#include <tiffio.h>
#include "spandsp/telephony.h"
#include "spandsp/logging.h"
#include "spandsp/queue.h"
#include "spandsp/dc_restore.h"
#include "spandsp/bit_operations.h"
#include "spandsp/power_meter.h"
#include "spandsp/complex.h"
#include "spandsp/tone_generate.h"
#include "spandsp/async.h"
#include "spandsp/crc.h"
#include "spandsp/hdlc.h"
#include "spandsp/silence_gen.h"
#include "spandsp/fsk.h"
#include "spandsp/v29rx.h"
#include "spandsp/v29tx.h"
#include "spandsp/v27ter_rx.h"
#include "spandsp/v27ter_tx.h"
#include "spandsp/v17rx.h"
#include "spandsp/v17tx.h"
#include "spandsp/t4.h"
#include "spandsp/t30_fcf.h"
#include "spandsp/t35.h"
#include "spandsp/t30.h"
#include "spandsp/t38_core.h"
#include "spandsp/t38_gateway.h"

Defines

#define MS_PER_TX_CHUNK   30
#define INDICATOR_TX_COUNT   3
#define DATA_TX_COUNT   1
#define DATA_END_TX_COUNT   1
#define DISBIT1   0x01
#define DISBIT2   0x02
#define DISBIT3   0x04
#define DISBIT4   0x08
#define DISBIT5   0x10
#define DISBIT6   0x20
#define DISBIT7   0x40
#define DISBIT8   0x80

Enumerations

enum  { T38_NONE, T38_V27TER_RX, T38_V29_RX, T38_V17_RX }
enum  { HDLC_FLAG_FINISHED = 0x01, HDLC_FLAG_CORRUPT_CRC = 0x02, HDLC_FLAG_PROCEED_WITH_OUTPUT = 0x04, HDLC_FLAG_MISSING_DATA = 0x08 }

Functions

int t38_gateway_rx (t38_gateway_state_t *s, int16_t amp[], int len)
 Process a block of received FAX audio samples.
int t38_gateway_tx (t38_gateway_state_t *s, int16_t amp[], int max_len)
 Generate a block of FAX audio samples.
void t38_gateway_set_ecm_capability (t38_gateway_state_t *s, int ecm_allowed)
 Control whether error correcting mode (ECM) is allowed.
void t38_gateway_set_transmit_on_idle (t38_gateway_state_t *s, int transmit_on_idle)
 Select whether silent audio will be sent when transmit is idle.
void t38_gateway_set_supported_modems (t38_gateway_state_t *s, int supported_modems)
 Specify supported modems.
void t38_gateway_set_nsx_suppression (t38_gateway_state_t *s, int suppress_nsx)
 Select whether NSC, NSF, and NSS should be suppressed.
void t38_gateway_set_tep_mode (t38_gateway_state_t *s, int use_tep)
 Select whether TEP will be sent for the image modems.
t38_gateway_state_t * t38_gateway_init (t38_gateway_state_t *s, t38_tx_packet_handler_t *tx_packet_handler, void *tx_packet_user_data)
 Initialise a gateway mode T.38 context.

Detailed Description


Function Documentation

t38_gateway_state_t* t38_gateway_init ( t38_gateway_state_t *  s,
t38_tx_packet_handler_t *  tx_packet_handler,
void *  tx_packet_user_data 
)

Initialise a gateway mode T.38 context.

Parameters:
s The T.38 context.
tx_packet_handler A callback routine to encapsulate and transmit T.38 packets.
tx_packet_user_data An opaque pointer passed to the tx_packet_handler routine.
Returns:
A pointer to the termination mode T.38 context, or NULL if there was a problem.

int t38_gateway_rx ( t38_gateway_state_t *  s,
int16_t  amp[],
int  len 
)

Process a block of received FAX audio samples.

Process a block of received FAX audio samples.

Parameters:
s The T.38 context.
amp The audio sample buffer.
len The number of samples in the buffer.
Returns:
The number of samples unprocessed.

void t38_gateway_set_ecm_capability ( t38_gateway_state_t *  s,
int  ecm_allowed 
)

Control whether error correcting mode (ECM) is allowed.

Control whether error correcting mode (ECM) is allowed.

Parameters:
s The T.38 context.
ecm_allowed TRUE is ECM is to be allowed.

void t38_gateway_set_nsx_suppression ( t38_gateway_state_t *  s,
int  suppress_nsx 
)

Select whether NSC, NSF, and NSS should be suppressed.

Select whether NSC, NSF, and NSS should be suppressed. It selected, the contents of these messages are forced to zero for all octets beyond the message type. This makes them look like manufacturer specific messages, from a manufacturer which does not exist.

Parameters:
s The T.38 context.
suppress_nsx TRUE if NSC, NSF, and NSS should be suppressed.

void t38_gateway_set_supported_modems ( t38_gateway_state_t *  s,
int  supported_modems 
)

Specify supported modems.

Specify which modem types are supported by a T.30 context.

Parameters:
s The T.38 context.
supported_modems Bit field list of the supported modems.

void t38_gateway_set_tep_mode ( t38_gateway_state_t *  s,
int  use_tep 
)

Select whether TEP will be sent for the image modems.

Select whether talker echo protection tone will be sent for the image modems.

Parameters:
s The T.38 context.
use_tep TRUE if TEP should be sent.

void t38_gateway_set_transmit_on_idle ( t38_gateway_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.38 context.
transmit_on_idle TRUE if silent audio should be output when the FAX transmitter is idle. FALSE to transmit zero length audio when the FAX transmitter is idle. The default behaviour is FALSE.

int t38_gateway_tx ( t38_gateway_state_t *  s,
int16_t  amp[],
int  max_len 
)

Generate a block of FAX audio samples.

Generate a block of FAX audio samples.

Parameters:
s The T.38 context.
amp The audio sample buffer.
max_len The number of samples to be generated.
Returns:
The number of samples actually generated.


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