spandsp 3.0.0
v18.h
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1/*
2 * SpanDSP - a series of DSP components for telephony
3 *
4 * v18.h - V.18 text telephony for the deaf.
5 *
6 * Written by Steve Underwood <steveu@coppice.org>
7 *
8 * Copyright (C) 2004-2009 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/*! \page v18_page The V.18 text telephony protocols
29\section v18_page_sec_1 What does it do?
30
31\section v18_page_sec_2 How does it work?
32*/
33
34#if !defined(_SPANDSP_V18_H_)
35#define _SPANDSP_V18_H_
36
37typedef struct v18_state_s v18_state_t;
38
39enum
40{
41 V18_MODE_NONE = 0x0001,
42 /* V.18 Annex A - Weitbrecht TDD at 45.45bps (US TTY), half-duplex, 5 bit baudot (USA). */
43 V18_MODE_WEITBRECHT_5BIT_4545 = 0x0002,
44 /* V.18 Annex A - Weitbrecht TDD at 50bps (International TTY), half-duplex, 5 bit baudot (UK, Australia and others). */
45 V18_MODE_WEITBRECHT_5BIT_50 = 0x0004,
46 /* V.18 Annex B - DTMF encoding of ASCII (Denmark, Holland and others). */
47 V18_MODE_DTMF = 0x0008,
48 /* V.18 Annex C - EDT (European Deaf Telephone) 110bps, V.21, half-duplex, ASCII (Germany, Austria, Switzerland and others). */
49 V18_MODE_EDT = 0x0010,
50 /* V.18 Annex D - 300bps, Bell 103, duplex, ASCII (USA). */
51 V18_MODE_BELL103 = 0x0020,
52 /* V.18 Annex E - 1200bps Videotex terminals, ASCII (France). */
53 V18_MODE_V23VIDEOTEX = 0x0040,
54 /* V.18 Annex F - V.21 text telephone, V.21, duplex, ASCII (Sweden, Norway and Finland). */
55 V18_MODE_V21TEXTPHONE = 0x0080,
56 /* V.18 Annex G - V.18 text telephone mode. */
57 V18_MODE_V18TEXTPHONE = 0x0100,
58 /* V.18 Annex A - Used during probing. */
59 V18_MODE_WEITBRECHT_5BIT_476 = 0x0200,
60 /* Use repetitive shift characters where character set shifts are used */
61 V18_MODE_REPETITIVE_SHIFTS_OPTION = 0x1000
62};
63
64/* Automoding sequences for different countries */
65enum v18_autobauding_modes_e
66{
67 V18_AUTOMODING_GLOBAL = 0,
68
69 V18_AUTOMODING_NONE,
70
71 /* 5-bit, V.21, V.23, EDT, DTMF, Bell 103 */
72 V18_AUTOMODING_AUSTRALIA,
73 V18_AUTOMODING_IRELAND,
74
75 /* EDT, V.21, V.23, 5-bit, DTMF, Bell 103 */
76 V18_AUTOMODING_GERMANY,
77 V18_AUTOMODING_SWITZERLAND,
78 V18_AUTOMODING_ITALY,
79 V18_AUTOMODING_SPAIN,
80 V18_AUTOMODING_AUSTRIA,
81
82 /* DTMF, V.21, V.23, 5-bit, EDT, Bell 103 */
83 V18_AUTOMODING_NETHERLANDS,
84
85 /* V.21, DTMF, 5-bit, EDT, V.23, Bell 103 */
86 V18_AUTOMODING_ICELAND,
87 V18_AUTOMODING_NORWAY,
88 V18_AUTOMODING_SWEDEN,
89 V18_AUTOMODING_FINALND,
90 V18_AUTOMODING_DENMARK,
91
92 /* V.21, 5-bit, V.23, EDT, DTMF, Bell 103 */
93 V18_AUTOMODING_UK,
94
95 /* 5-bit, Bell 103, V.21, V.23, EDT, DTMF */
96 V18_AUTOMODING_USA,
97
98 /* V.23, EDT, DTMF, 5-bit, V.21, Bell 103 */
99 V18_AUTOMODING_FRANCE,
100 V18_AUTOMODING_BELGIUM,
101
102 V18_AUTOMODING_END
103};
104
105enum v18_status_e
106{
107 V18_STATUS_SWITCH_TO_NONE,
108 V18_STATUS_SWITCH_TO_WEITBRECHT_5BIT_4545,
109 V18_STATUS_SWITCH_TO_WEITBRECHT_5BIT_476,
110 V18_STATUS_SWITCH_TO_WEITBRECHT_5BIT_50,
111 V18_STATUS_SWITCH_TO_DTMF,
112 V18_STATUS_SWITCH_TO_EDT,
113 V18_STATUS_SWITCH_TO_BELL103,
114 V18_STATUS_SWITCH_TO_V23VIDEOTEX,
115 V18_STATUS_SWITCH_TO_V21TEXTPHONE,
116 V18_STATUS_SWITCH_TO_V18TEXTPHONE
117};
118
119#if defined(__cplusplus)
120extern "C"
121{
122#endif
123
124SPAN_DECLARE(logging_state_t *) v18_get_logging_state(v18_state_t *s);
125
126/*! Initialise a V.18 context.
127 \brief Initialise a V.18 context.
128 \param s The V.18 context.
129 \param calling_party True if caller mode, else answerer mode.
130 \param mode Mode of operation.
131 \param nation National variant for automoding.
132 \param put_msg A callback routine called to deliver the received text
133 to the application.
134 \param put_msg_user_data An opaque pointer for the put_msg callback routine.
135 \param status_handler A callback routine called to deliver status reports.
136 \param status_handler_user_data An opaque pointer for the status callback routine.
137 \return A pointer to the V.18 context, or NULL if there was a problem. */
138SPAN_DECLARE(v18_state_t *) v18_init(v18_state_t *s,
139 bool calling_party,
140 int mode,
141 int nation,
142 span_put_msg_func_t put_msg,
143 void *put_msg_user_data,
144 span_modem_status_func_t status_handler,
145 void *status_handler_user_data);
146
147/*! Release a V.18 context.
148 \brief Release a V.18 context.
149 \param s The V.18 context.
150 \return 0 for OK. */
151SPAN_DECLARE(int) v18_release(v18_state_t *s);
152
153/*! Free a V.18 context.
154 \brief Release a V.18 context.
155 \param s The V.18 context.
156 \return 0 for OK. */
157SPAN_DECLARE(int) v18_free(v18_state_t *s);
158
159/*! Generate a block of V.18 audio samples.
160 \brief Generate a block of V.18 audio samples.
161 \param s The V.18 context.
162 \param amp The audio sample buffer.
163 \param max_len The number of samples to be generated.
164 \return The number of samples actually generated.
165*/
166SPAN_DECLARE(int) v18_tx(v18_state_t *s, int16_t amp[], int max_len);
167
168/*! Process a block of received V.18 audio samples.
169 \brief Process a block of received V.18 audio samples.
170 \param s The V.18 context.
171 \param amp The audio sample buffer.
172 \param len The number of samples in the buffer.
173 \return The number of unprocessed samples.
174*/
175SPAN_DECLARE(int) v18_rx(v18_state_t *s, const int16_t amp[], int len);
176
177/*! Fake processing of a missing block of received V.18 audio samples.
178 (e.g due to packet loss).
179 \brief Fake processing of a missing block of received V.18 audio samples.
180 \param s The V.18 context.
181 \param len The number of samples to fake.
182 \return The number of unprocessed samples.
183*/
184SPAN_DECLARE(int) v18_rx_fillin(v18_state_t *s, int len);
185
186/*! \brief Put a string to a V.18 context's input buffer.
187 \param s The V.18 context.
188 \param msg The string to be added.
189 \param len The length of the string. If negative, the string is
190 assumed to be a NULL terminated string.
191 \return The number of characters actually added. This may be less than the
192 length of the digit string, if the buffer fills up. If the string is
193 invalid, this function will return -1. */
194SPAN_DECLARE(int) v18_put(v18_state_t *s, const char msg[], int len);
195
196/*! \brief Set the stored message, as per V.18/5.2.12.1. This message may be up
197 to 80 bytes long.
198 \param s The V.18 context.
199 \param msg The string to be set.
200*/
201SPAN_DECLARE(int) v18_set_stored_message(v18_state_t *s, const char *msg);
202
203/*! \brief Get the current mode of a V.18 connection.
204 \param s The V.18 context.
205 \return The mode. */
206SPAN_DECLARE(int) v18_get_current_mode(v18_state_t *s);
207
208/*! \brief Return a short name for a V.18 mode
209 \param mode The code for the V.18 mode.
210 \return A pointer to the name.
211*/
212SPAN_DECLARE(const char *) v18_mode_to_str(int mode);
213
214SPAN_DECLARE(const char *) v18_status_to_str(int status);
215
216#if defined(__cplusplus)
217}
218#endif
219
220#endif
221/*- End of file ------------------------------------------------------------*/
void(* span_modem_status_func_t)(void *user_data, int status)
Definition async.h:131
void(* span_put_msg_func_t)(void *user_data, const uint8_t *msg, int len)
Definition async.h:107
struct logging_state_s logging_state_t
Definition logging.h:72
Definition private/v18.h:70
int v18_free(v18_state_t *s)
Release a V.18 context.
Definition v18.c:2125
int v18_rx(v18_state_t *s, const int16_t amp[], int len)
Process a block of received V.18 audio samples.
Definition v18.c:1874
const char * v18_mode_to_str(int mode)
Return a short name for a V.18 mode.
Definition v18.c:710
v18_state_t * v18_init(v18_state_t *s, bool calling_party, int mode, int nation, span_put_msg_func_t put_msg, void *put_msg_user_data, span_modem_status_func_t status_handler, void *status_handler_user_data)
Initialise a V.18 context.
Definition v18.c:2054
int v18_rx_fillin(v18_state_t *s, int len)
Fake processing of a missing block of received V.18 audio samples.
Definition v18.c:1943
int v18_set_stored_message(v18_state_t *s, const char *msg)
Set the stored message, as per V.18/5.2.12.1. This message may be up to 80 bytes long.
Definition v18.c:2047
int v18_tx(v18_state_t *s, int16_t amp[], int max_len)
Generate a block of V.18 audio samples.
int v18_get_current_mode(v18_state_t *s)
Get the current mode of a V.18 connection.
Definition v18.c:2019
int v18_put(v18_state_t *s, const char msg[], int len)
Put a string to a V.18 context's input buffer.
Definition v18.c:1990
int v18_release(v18_state_t *s)
Release a V.18 context.
Definition v18.c:2118