spandsp: t38_core.h Source File

spandsp 0.0.6

t38_core.h
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1/*
2 * SpanDSP - a series of DSP components for telephony
3 *
4 * t38_core.h - An implementation of T.38, less the packet exchange part
5 *
6 * Written by Steve Underwood <steveu@coppice.org>
7 *
8 * Copyright (C) 2005 Steve Underwood
9 *
10 * All rights reserved.
11 *
12 * This program is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU Lesser General Public License version 2.1,
14 * as published by the Free Software Foundation.
15 *
16 * This program is distributed in the hope that it will be useful,
17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19 * GNU Lesser General Public License for more details.
20 *
21 * You should have received a copy of the GNU Lesser General Public
22 * License along with this program; if not, write to the Free Software
23 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
24 */
25
26/*! \file */
27
28#if !defined(_SPANDSP_T38_CORE_H_)
29#define _SPANDSP_T38_CORE_H_
30
31/*! \page t38_core_page T.38 real time FAX over IP message handling
32There are two ITU recommendations which address sending FAXes over IP networks. T.37 specifies a
33method of encapsulating FAX images in e-mails, and transporting them to the recipient (an e-mail
34box, or another FAX machine) in a store-and-forward manner. T.38 defines a protocol for
35transmitting a FAX across an IP network in real time. The core T.38 modules implements the basic
36message handling for the T.38, real time, FAX over IP (FoIP) protocol.
37
38The T.38 protocol can operate between:
39 - Internet-aware FAX terminals, which connect directly to an IP network. The T.38 terminal module
40 extends this module to provide a complete T.38 terminal.
41 - FAX gateways, which allow traditional PSTN FAX terminals to communicate through the Internet.
42 The T.38 gateway module extends this module to provide a T.38 gateway.
43 - A combination of terminals and gateways.
44
45T.38 is the only standardised protocol which exists for real-time FoIP. Reliably transporting a
46FAX between PSTN FAX terminals, through an IP network, requires use of the T.38 protocol at FAX
47gateways. VoIP connections are not robust for modem use, including FAX modem use. Most use low
48bit rate codecs, which cannot convey the modem signals accurately. Even when high bit rate
49codecs are used, VoIP connections suffer dropouts and timing adjustments, which modems cannot
50tolerate. In a LAN environment the dropout rate may be very low, but the timing adjustments which
51occur in VoIP connections still make modem operation unreliable. T.38 FAX gateways deal with the
52delays, timing jitter, and packet loss experienced in packet networks, and isolate the PSTN FAX
53terminals from these as far as possible. In addition, by sending FAXes as image data, rather than
54digitised audio, they reduce the required bandwidth of the IP network.
55
56\section t38_core_page_sec_1 What does it do?
57
58\section t38_core_page_sec_2 How does it work?
59
60Timing differences and jitter between two T.38 entities can be a serious problem, if one of those
61entities is a PSTN gateway.
62
63Flow control for non-ECM image data takes advantage of several features of the T.30 specification.
64First, an unspecified number of 0xFF octets may be sent at the start of transmission. This means we
65can add endless extra 0xFF bytes at this point, without breaking the T.30 spec. In practice, we
66cannot add too many, or we will affect the timing tolerance of the T.30 protocol by delaying the
67response at the end of each image. Secondly, just before an end of line (EOL) marker we can pad
68with zero bits. Again, the number is limited only by need to avoid upsetting the timing of the
69step following the non-ECM data.
70*/
71
72/*! T.38 indicator types */
73 enum t30_indicator_types_e
74{
75 T38_IND_NO_SIGNAL = 0,
76 T38_IND_CNG,
77 T38_IND_CED,
78 T38_IND_V21_PREAMBLE,
79 T38_IND_V27TER_2400_TRAINING,
80 T38_IND_V27TER_4800_TRAINING,
81 T38_IND_V29_7200_TRAINING,
82 T38_IND_V29_9600_TRAINING,
83 T38_IND_V17_7200_SHORT_TRAINING,
84 T38_IND_V17_7200_LONG_TRAINING,
85 T38_IND_V17_9600_SHORT_TRAINING,
86 T38_IND_V17_9600_LONG_TRAINING,
87 T38_IND_V17_12000_SHORT_TRAINING,
88 T38_IND_V17_12000_LONG_TRAINING,
89 T38_IND_V17_14400_SHORT_TRAINING,
90 T38_IND_V17_14400_LONG_TRAINING,
91 T38_IND_V8_ANSAM,
92 T38_IND_V8_SIGNAL,
93 T38_IND_V34_CNTL_CHANNEL_1200,
94 T38_IND_V34_PRI_CHANNEL,
95 T38_IND_V34_CC_RETRAIN,
96 T38_IND_V33_12000_TRAINING,
97 T38_IND_V33_14400_TRAINING
98};
99
100/*! T.38 data types */
101 enum t38_data_types_e
102{
103 T38_DATA_NONE = -1,
104 T38_DATA_V21 = 0,
105 T38_DATA_V27TER_2400,
106 T38_DATA_V27TER_4800,
107 T38_DATA_V29_7200,
108 T38_DATA_V29_9600,
109 T38_DATA_V17_7200,
110 T38_DATA_V17_9600,
111 T38_DATA_V17_12000,
112 T38_DATA_V17_14400,
113 T38_DATA_V8,
114 T38_DATA_V34_PRI_RATE,
115 T38_DATA_V34_CC_1200,
116 T38_DATA_V34_PRI_CH,
117 T38_DATA_V33_12000,
118 T38_DATA_V33_14400
119};
120
121/*! T.38 data field types */
122 enum t38_field_types_e
123{
124 T38_FIELD_HDLC_DATA = 0,
125 T38_FIELD_HDLC_SIG_END,
126 T38_FIELD_HDLC_FCS_OK,
127 T38_FIELD_HDLC_FCS_BAD,
128 T38_FIELD_HDLC_FCS_OK_SIG_END,
129 T38_FIELD_HDLC_FCS_BAD_SIG_END,
130 T38_FIELD_T4_NON_ECM_DATA,
131 T38_FIELD_T4_NON_ECM_SIG_END,
132 T38_FIELD_CM_MESSAGE,
133 T38_FIELD_JM_MESSAGE,
134 T38_FIELD_CI_MESSAGE,
135 T38_FIELD_V34RATE
136};
137
138/*! T.38 field classes */
139 enum t38_field_classes_e
140{
141 T38_FIELD_CLASS_NONE = 0,
142 T38_FIELD_CLASS_HDLC,
143 T38_FIELD_CLASS_NON_ECM
144};
145
146/*! T.38 message types */
147 enum t38_message_types_e
148{
149 T38_TYPE_OF_MSG_T30_INDICATOR = 0,
150 T38_TYPE_OF_MSG_T30_DATA
151};
152
153/*! T.38 transport types */
154 enum t38_transport_types_e
155{
156 T38_TRANSPORT_UDPTL = 0,
157 T38_TRANSPORT_RTP,
158 T38_TRANSPORT_TCP,
159 T38_TRANSPORT_TCP_TPKT
160};
161
162/*! T.38 TCF management types */
163 enum t38_data_rate_management_types_e
164{
165 T38_DATA_RATE_MANAGEMENT_LOCAL_TCF = 1,
166 T38_DATA_RATE_MANAGEMENT_TRANSFERRED_TCF = 2
167};
168
169/*! T.38 Packet categories used for setting the redundancy level and packet repeat
170 counts on a packet by packet basis. */
171 enum t38_packet_categories_e
172{
173 /*! \brief Indicator packet */
174 T38_PACKET_CATEGORY_INDICATOR = 0,
175 /*! \brief Control data packet */
176 T38_PACKET_CATEGORY_CONTROL_DATA = 1,
177 /*! \brief Terminating control data packet */
178 T38_PACKET_CATEGORY_CONTROL_DATA_END = 2,
179 /*! \brief Image data packet */
180 T38_PACKET_CATEGORY_IMAGE_DATA = 3,
181 /*! \brief Terminating image data packet */
182 T38_PACKET_CATEGORY_IMAGE_DATA_END = 4
183};
184
185#define T38_RX_BUF_LEN 2048
186#define T38_TX_BUF_LEN 16384
187
188/*! T.38 data field */
189 typedef struct
190{
191 /*! Field type */
192 int field_type;
193 /*! Field contents */
194 const uint8_t *field;
195 /*! Field length */
196 int field_len;
197} t38_data_field_t;
198
199/*!
200 Core T.38 state, common to all modes of T.38.
201*/
202 typedef struct t38_core_state_s t38_core_state_t;
203
204typedef int (t38_tx_packet_handler_t)(t38_core_state_t *s, void *user_data, const uint8_t *buf, int len, int count);
205
206typedef int (t38_rx_indicator_handler_t)(t38_core_state_t *s, void *user_data, int indicator);
207typedef int (t38_rx_data_handler_t)(t38_core_state_t *s, void *user_data, int data_type, int field_type, const uint8_t *buf, int len);
208typedef int (t38_rx_missing_handler_t)(t38_core_state_t *s, void *user_data, int rx_seq_no, int expected_seq_no);
209
210#if defined(__cplusplus)
211extern "C"
212{
213#endif
214
215/*! \brief Convert the code for an indicator to a short text name.
216 \param indicator The type of indicator.
217 \return A pointer to a short text name for the indicator. */
218SPAN_DECLARE(const char *) t38_indicator_to_str(int indicator);
219
220/*! \brief Convert the code for a type of data to a short text name.
221 \param data_type The data type.
222 \return A pointer to a short text name for the data type. */
223SPAN_DECLARE(const char *) t38_data_type_to_str(int data_type);
224
225/*! \brief Convert the code for a type of data field to a short text name.
226 \param field_type The field type.
227 \return A pointer to a short text name for the field type. */
228SPAN_DECLARE(const char *) t38_field_type_to_str(int field_type);
229
230/*! \brief Convert the code for a CM profile code to text description.
231 \param profile The profile code from a CM message.
232 \return A pointer to a short text description of the profile. */
233SPAN_DECLARE(const char *) t38_cm_profile_to_str(int profile);
234
235/*! \brief Convert a JM message code to text description.
236 \param data The data field of the message.
237 \param len The length of the data field.
238 \return A pointer to a short text description of the profile. */
239SPAN_DECLARE(const char *) t38_jm_to_str(const uint8_t *data, int len);
240
241/*! \brief Convert a V34rate message to an actual bit rate.
242 \param data The data field of the message.
243 \param len The length of the data field.
244 \return The bit rate, or -1 for a bad message. */
245SPAN_DECLARE(int) t38_v34rate_to_bps(const uint8_t *data, int len);
246
247/*! \brief Send an indicator packet
248 \param s The T.38 context.
249 \param indicator The indicator to send.
250 \return The delay to allow after this indicator is sent. */
251SPAN_DECLARE(int) t38_core_send_indicator(t38_core_state_t *s, int indicator);
252
253/*! \brief Find the delay to allow for HDLC flags after sending an indicator
254 \param s The T.38 context.
255 \param indicator The indicator to check.
256 \return The delay to allow for initial HDLC flags after this indicator is sent. */
257SPAN_DECLARE(int) t38_core_send_flags_delay(t38_core_state_t *s, int indicator);
258
259/*! \brief Find the delay to allow for modem training after sending an indicator
260 \param s The T.38 context.
261 \param indicator The indicator to check.
262 \return The delay to allow for modem training after this indicator is sent. */
263SPAN_DECLARE(int) t38_core_send_training_delay(t38_core_state_t *s, int indicator);
264
265/*! \brief Send a data packet
266 \param s The T.38 context.
267 \param data_type The packet's data type.
268 \param field_type The packet's field type.
269 \param field The message data content for the packet.
270 \param field_len The length of the message data, in bytes.
271 \param category The category of the packet being sent. This should be one of the values defined for t38_packet_categories_e.
272 \return 0 for OK, else -1 */
273SPAN_DECLARE(int) t38_core_send_data(t38_core_state_t *s, int data_type, int field_type, const uint8_t field[], int field_len, int category);
274
275/*! \brief Send a data packet
276 \param s The T.38 context.
277 \param data_type The packet's data type.
278 \param field The list of fields.
279 \param fields The number of fields in the list.
280 \param category The category of the packet being sent. This should be one of the values defined for t38_packet_categories_e.
281 \return 0 for OK, else -1 */
282SPAN_DECLARE(int) t38_core_send_data_multi_field(t38_core_state_t *s, int data_type, const t38_data_field_t field[], int fields, int category);
283
284/*! \brief Process a received T.38 IFP packet from an unreliable packet stream (e.g. UDPTL or RTP). This processing includes
285 packet sequence number checking, missing packet recovery, and skipping repeat packets.
286 \param s The T.38 context.
287 \param buf The packet contents.
288 \param len The length of the packet contents.
289 \param seq_no The packet sequence number.
290 \return 0 for OK, else -1. */
291 SPAN_DECLARE_NONSTD(int) t38_core_rx_ifp_packet(t38_core_state_t *s, const uint8_t *buf, int len, uint16_t seq_no);
292
293/*! \brief Process a received T.38 IFP packet from a reliable stream (e.g. TCP).
294 \param s The T.38 context.
295 \param buf The packet contents.
296 \param len The length of the packet contents.
297 \param seq_no The packet sequence number, used for logging purposes.
298 \return The length of the packet processed, or -1 if there is an error in the packet, or too few bytes of data to complete it. */
299 SPAN_DECLARE_NONSTD(int) t38_core_rx_ifp_stream(t38_core_state_t *s, const uint8_t *buf, int len, uint16_t log_seq_no);
300
301/*! Set the method to be used for data rate management, as per the T.38 spec.
302 \param s The T.38 context.
303 \param method 1 for pass TCF across the T.38 link, 2 for handle TCF locally.
304*/
305SPAN_DECLARE(void) t38_set_data_rate_management_method(t38_core_state_t *s, int method);
306
307/*! Set the data transport protocol.
308 \param s The T.38 context.
309 \param data_transport_protocol UDPTL, RTP or TPKT.
310*/
311SPAN_DECLARE(void) t38_set_data_transport_protocol(t38_core_state_t *s, int data_transport_protocol);
312
313/*! Set the non-ECM fill bit removal mode.
314 \param s The T.38 context.
315 \param fill_bit_removal TRUE to remove fill bits across the T.38 link, else FALSE.
316*/
317SPAN_DECLARE(void) t38_set_fill_bit_removal(t38_core_state_t *s, int fill_bit_removal);
318
319/*! Set the MMR transcoding mode.
320 \param s The T.38 context.
321 \param mmr_transcoding TRUE to transcode to MMR across the T.38 link, else FALSE.
322*/
323SPAN_DECLARE(void) t38_set_mmr_transcoding(t38_core_state_t *s, int mmr_transcoding);
324
325/*! Set the JBIG transcoding mode.
326 \param s The T.38 context.
327 \param jbig_transcoding TRUE to transcode to JBIG across the T.38 link, else FALSE.
328*/
329SPAN_DECLARE(void) t38_set_jbig_transcoding(t38_core_state_t *s, int jbig_transcoding);
330
331/*! Set the maximum buffer size for received data at the far end.
332 \param s The T.38 context.
333 \param max_buffer_size The maximum buffer size.
334*/
335SPAN_DECLARE(void) t38_set_max_buffer_size(t38_core_state_t *s, int max_buffer_size);
336
337/*! Set the maximum size of an IFP packet that is acceptable by the far end.
338 \param s The T.38 context.
339 \param max_datagram_size The maximum IFP packet length, in bytes.
340*/
341SPAN_DECLARE(void) t38_set_max_datagram_size(t38_core_state_t *s, int max_datagram_size);
342
343/*! \brief Send a data packet
344 \param s The T.38 context.
345 \param category The category of the packet being sent. This should be one of the values defined for t38_packet_categories_e.
346 \param setting The repeat count for the category. This should be at least one for all categories other an indicator packets.
347 Zero is valid for indicator packets, as it suppresses the sending of indicator packets, as an application using
348 TCP for the transport would require. As the setting is passed through to the transmission channel, additional
349 information may be encoded in it, such as the redundancy depth for the particular packet category. */
350SPAN_DECLARE(void) t38_set_redundancy_control(t38_core_state_t *s, int category, int setting);
351
352SPAN_DECLARE(void) t38_set_pace_transmission(t38_core_state_t *s, int pace_transmission);
353
354SPAN_DECLARE(void) t38_set_fastest_image_data_rate(t38_core_state_t *s, int max_rate);
355
356SPAN_DECLARE(int) t38_get_fastest_image_data_rate(t38_core_state_t *s);
357
358/*! Set the T.38 version to be emulated.
359 \param s The T.38 context.
360 \param t38_version Version number, as in the T.38 spec.
361*/
362SPAN_DECLARE(void) t38_set_t38_version(t38_core_state_t *s, int t38_version);
363
364/*! Set the sequence number handling option.
365 \param s The T.38 context.
366 \param check TRUE to check sequence numbers, and handle gaps reasonably. FALSE
367 for no sequence number processing (e.g. for TPKT over TCP transport).
368*/
369SPAN_DECLARE(void) t38_set_sequence_number_handling(t38_core_state_t *s, int check);
370
371/*! Set the TEP handling option.
372 \param s The T.38 context.
373 \param allow_for_tep TRUE to allow for TEP playout, else FALSE.
374*/
375SPAN_DECLARE(void) t38_set_tep_handling(t38_core_state_t *s, int allow_for_tep);
376
377/*! Get a pointer to the logging context associated with a T.38 context.
378 \brief Get a pointer to the logging context associated with a T.38 context.
379 \param s The T.38 context.
380 \return A pointer to the logging context, or NULL.
381*/
382SPAN_DECLARE(logging_state_t *) t38_core_get_logging_state(t38_core_state_t *s);
383
384/*! Restart a T.38 core context.
385 \brief Restart a T.38 core context.
386 \param s The T.38 context.
387 \return 0 for OK, else -1. */
388SPAN_DECLARE(int) t38_core_restart(t38_core_state_t *s);
389
390/*! Initialise a T.38 core context.
391 \brief Initialise a T.38 core context.
392 \param s The T.38 context.
393 \param rx_indicator_handler Receive indicator handling routine.
394 \param rx_data_handler Receive data packet handling routine.
395 \param rx_rx_missing_handler Missing receive packet handling routine.
396 \param rx_packet_user_data An opaque pointer passed to the rx packet handling routines.
397 \param tx_packet_handler Packet transmit handling routine.
398 \param tx_packet_user_data An opaque pointer passed to the tx_packet_handler.
399 \return A pointer to the T.38 context, or NULL if there was a problem. */
400SPAN_DECLARE(t38_core_state_t *) t38_core_init(t38_core_state_t *s,
401 t38_rx_indicator_handler_t *rx_indicator_handler,
402 t38_rx_data_handler_t *rx_data_handler,
403 t38_rx_missing_handler_t *rx_missing_handler,
404 void *rx_user_data,
405 t38_tx_packet_handler_t *tx_packet_handler,
406 void *tx_packet_user_data);
407
408/*! Release a signaling tone transmitter context.
409 \brief Release a signaling tone transmitter context.
410 \param s The T.38 context.
411 \return 0 for OK */
412SPAN_DECLARE(int) t38_core_release(t38_core_state_t *s);
413
414/*! Free a signaling tone transmitter context.
415 \brief Free a signaling tone transmitter context.
416 \param s The T.38 context.
417 \return 0 for OK */
418SPAN_DECLARE(int) t38_core_free(t38_core_state_t *s);
419
420#if defined(__cplusplus)
421}
422#endif
423
424#endif
425/*- End of file ------------------------------------------------------------*/
SPAN_DECLARE_NONSTD
SPAN_DECLARE_NONSTD(void) async_rx_put_bit(void *user_data
Accept a bit from a received serial bit stream.
logging_state_t
struct logging_state_s logging_state_t
Definition logging.h:75
t38_core_state_s
Definition private/t38_core.h:33
t38_core_state_s::max_buffer_size
int max_buffer_size
For UDP (UDPTL or RTP) modes, this option indicates the maximum number of octets that can be stored o...
Definition private/t38_core.h:81
t38_core_state_s::fill_bit_removal
int fill_bit_removal
Indicates the capability to remove and insert fill bits in Phase C, non-ECM data to reduce bandwidth ...
Definition private/t38_core.h:65
t38_core_state_s::data_transport_protocol
int data_transport_protocol
The emitting gateway may indicate a preference for either UDP/UDPTL, or UDP/RTP, or TCP for transport...
Definition private/t38_core.h:61
t38_core_state_s::max_datagram_size
int max_datagram_size
This option indicates the maximum size of a UDPTL packet or the maximum size of the payload within an...
Definition private/t38_core.h:86
t38_core_state_s::rx_user_data
void * rx_user_data
An opaque pointer passed to any of the above receive handling routines.
Definition private/t38_core.h:46
t38_core_state_s::pace_transmission
int pace_transmission
Pace transmission.
Definition private/t38_core.h:99
t38_core_state_s::jbig_transcoding
int jbig_transcoding
Indicates the ability to convert to/from JBIG to reduce bandwidth.
Definition private/t38_core.h:73
t38_core_state_s::tx_packet_user_data
void * tx_packet_user_data
An opaque pointer passed to tx_packet_handler.
Definition private/t38_core.h:37
t38_core_state_s::mmr_transcoding
int mmr_transcoding
Indicates the ability to convert to/from MMR from/to the line format to improve the compression of th...
Definition private/t38_core.h:70
t38_core_state_s::allow_for_tep
int allow_for_tep
Allow time for TEP playout.
Definition private/t38_core.h:93
t38_data_field_t
Definition t38_core.h:190
t38_data_field_t::field
const uint8_t * field
Definition t38_core.h:194
t38_data_field_t::field_len
int field_len
Definition t38_core.h:196
t38_data_field_t::field_type
int field_type
Definition t38_core.h:192
t38_data_type_to_str
const char * t38_data_type_to_str(int data_type)
Convert the code for a type of data to a short text name.
Definition t38_core.c:148
t38_indicator_to_str
const char * t38_indicator_to_str(int indicator)
Convert the code for an indicator to a short text name.
Definition t38_core.c:93
t38_core_restart
int t38_core_restart(t38_core_state_t *s)
Restart a T.38 core context.
Definition t38_core.c:1082
t38_set_data_rate_management_method
void t38_set_data_rate_management_method(t38_core_state_t *s, int method)
Definition t38_core.c:992
t38_set_t38_version
void t38_set_t38_version(t38_core_state_t *s, int t38_version)
Definition t38_core.c:1034
t38_set_sequence_number_handling
void t38_set_sequence_number_handling(t38_core_state_t *s, int check)
Definition t38_core.c:1040
t38_set_data_transport_protocol
void t38_set_data_transport_protocol(t38_core_state_t *s, int data_transport_protocol)
Definition t38_core.c:998
t38_cm_profile_to_str
const char * t38_cm_profile_to_str(int profile)
Convert the code for a CM profile code to text description.
Definition t38_core.c:220
t38_data_types_e
t38_data_types_e
Definition t38_core.h:102
t38_core_get_logging_state
logging_state_t * t38_core_get_logging_state(t38_core_state_t *s)
Get a pointer to the logging context associated with a T.38 context.
Definition t38_core.c:1076
t38_core_send_data_multi_field
int t38_core_send_data_multi_field(t38_core_state_t *s, int data_type, const t38_data_field_t field[], int fields, int category)
Send a data packet.
Definition t38_core.c:972
t38_set_mmr_transcoding
void t38_set_mmr_transcoding(t38_core_state_t *s, int mmr_transcoding)
Definition t38_core.c:1010
t38_transport_types_e
t38_transport_types_e
Definition t38_core.h:155
t38_data_rate_management_types_e
t38_data_rate_management_types_e
Definition t38_core.h:164
t38_core_send_indicator
int t38_core_send_indicator(t38_core_state_t *s, int indicator)
Send an indicator packet.
Definition t38_core.c:889
t38_field_classes_e
t38_field_classes_e
Definition t38_core.h:140
t38_set_tep_handling
void t38_set_tep_handling(t38_core_state_t *s, int allow_for_tep)
Definition t38_core.c:1052
t38_core_state_t
struct t38_core_state_s t38_core_state_t
Definition t38_core.h:202
t38_set_fill_bit_removal
void t38_set_fill_bit_removal(t38_core_state_t *s, int fill_bit_removal)
Definition t38_core.c:1004
t38_core_send_training_delay
int t38_core_send_training_delay(t38_core_state_t *s, int indicator)
Find the delay to allow for modem training after sending an indicator.
Definition t38_core.c:940
t38_v34rate_to_bps
int t38_v34rate_to_bps(const uint8_t *data, int len)
Convert a V34rate message to an actual bit rate.
Definition t38_core.c:272
t38_packet_categories_e
t38_packet_categories_e
Definition t38_core.h:172
T38_PACKET_CATEGORY_IMAGE_DATA
@ T38_PACKET_CATEGORY_IMAGE_DATA
Image data packet.
Definition t38_core.h:180
T38_PACKET_CATEGORY_CONTROL_DATA_END
@ T38_PACKET_CATEGORY_CONTROL_DATA_END
Terminating control data packet.
Definition t38_core.h:178
T38_PACKET_CATEGORY_IMAGE_DATA_END
@ T38_PACKET_CATEGORY_IMAGE_DATA_END
Terminating image data packet.
Definition t38_core.h:182
T38_PACKET_CATEGORY_INDICATOR
@ T38_PACKET_CATEGORY_INDICATOR
Indicator packet.
Definition t38_core.h:174
T38_PACKET_CATEGORY_CONTROL_DATA
@ T38_PACKET_CATEGORY_CONTROL_DATA
Control data packet.
Definition t38_core.h:176
t38_message_types_e
t38_message_types_e
Definition t38_core.h:148
t38_core_release
int t38_core_release(t38_core_state_t *s)
Release a signaling tone transmitter context.
Definition t38_core.c:1151
t30_indicator_types_e
t30_indicator_types_e
Definition t38_core.h:74
t38_core_free
int t38_core_free(t38_core_state_t *s)
Free a signaling tone transmitter context.
Definition t38_core.c:1157
t38_core_init
t38_core_state_t * t38_core_init(t38_core_state_t *s, t38_rx_indicator_handler_t *rx_indicator_handler, t38_rx_data_handler_t *rx_data_handler, t38_rx_missing_handler_t *rx_missing_handler, void *rx_user_data, t38_tx_packet_handler_t *tx_packet_handler, void *tx_packet_user_data)
Initialise a T.38 core context.
Definition t38_core.c:1102
t38_field_types_e
t38_field_types_e
Definition t38_core.h:123
t38_core_send_flags_delay
int t38_core_send_flags_delay(t38_core_state_t *s, int indicator)
Find the delay to allow for HDLC flags after sending an indicator.
Definition t38_core.c:932
t38_jm_to_str
const char * t38_jm_to_str(const uint8_t *data, int len)
Convert a JM message code to text description.
Definition t38_core.c:241
t38_set_max_datagram_size
void t38_set_max_datagram_size(t38_core_state_t *s, int max_datagram_size)
Definition t38_core.c:1028
t38_core_send_data
int t38_core_send_data(t38_core_state_t *s, int data_type, int field_type, const uint8_t field[], int field_len, int category)
Send a data packet.
Definition t38_core.c:948
t38_set_jbig_transcoding
void t38_set_jbig_transcoding(t38_core_state_t *s, int jbig_transcoding)
Definition t38_core.c:1016
t38_set_max_buffer_size
void t38_set_max_buffer_size(t38_core_state_t *s, int max_buffer_size)
Definition t38_core.c:1022
t38_field_type_to_str
const char * t38_field_type_to_str(int field_type)
Convert the code for a type of data field to a short text name.
Definition t38_core.c:187
t38_set_redundancy_control
void t38_set_redundancy_control(t38_core_state_t *s, int category, int setting)
Send a data packet.
Definition t38_core.c:1058