t31.h

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00001 /*
00002  * SpanDSP - a series of DSP components for telephony
00003  *
00004  * t31.h - A T.31 compatible class 1 FAX modem interface.
00005  *
00006  * Written by Steve Underwood <steveu@coppice.org>
00007  *
00008  * Copyright (C) 2004 Steve Underwood
00009  *
00010  * All rights reserved.
00011  *
00012  * This program is free software; you can redistribute it and/or modify
00013  * it under the terms of the GNU Lesser General Public License version 2.1,
00014  * as published by the Free Software Foundation.
00015  *
00016  * This program is distributed in the hope that it will be useful,
00017  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00018  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00019  * GNU Lesser General Public License for more details.
00020  *
00021  * You should have received a copy of the GNU Lesser General Public
00022  * License along with this program; if not, write to the Free Software
00023  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
00024  *
00025  * $Id: t31.h,v 1.53 2008/10/13 13:14:00 steveu Exp $
00026  */
00027 
00028 /*! \file */
00029 
00030 #if !defined(_SPANDSP_T31_H_)
00031 #define _SPANDSP_T31_H_
00032 
00033 /*! \page t31_page T.31 Class 1 FAX modem protocol handling
00034 \section t31_page_sec_1 What does it do?
00035 The T.31 class 1 FAX modem modules implements a class 1 interface to the FAX
00036 modems in spandsp.
00037 
00038 \section t31_page_sec_2 How does it work?
00039 */
00040 
00041 /*!
00042     T.31 descriptor. This defines the working state for a single instance of
00043     a T.31 FAX modem.
00044 */
00045 typedef struct t31_state_s t31_state_t;
00046 
00047 typedef int (t31_modem_control_handler_t)(t31_state_t *s, void *user_data, int op, const char *num);
00048 
00049 #define T31_TX_BUF_LEN          (4096)
00050 #define T31_TX_BUF_HIGH_TIDE    (4096 - 1024)
00051 #define T31_TX_BUF_LOW_TIDE     (1024)
00052 #define T31_MAX_HDLC_LEN        284
00053 #define T31_T38_MAX_HDLC_LEN    260
00054 
00055 #if defined(__cplusplus)
00056 extern "C"
00057 {
00058 #endif
00059 
00060 void t31_call_event(t31_state_t *s, int event);
00061 
00062 int t31_at_rx(t31_state_t *s, const char *t, int len);
00063 
00064 /*! Process a block of received T.31 modem audio samples.
00065     \brief Process a block of received T.31 modem audio samples.
00066     \param s The T.31 modem context.
00067     \param amp The audio sample buffer.
00068     \param len The number of samples in the buffer.
00069     \return The number of samples unprocessed. */
00070 int t31_rx(t31_state_t *s, int16_t amp[], int len);
00071 
00072 /*! Generate a block of T.31 modem audio samples.
00073     \brief Generate a block of T.31 modem audio samples.
00074     \param s The T.31 modem context.
00075     \param amp The audio sample buffer.
00076     \param max_len The number of samples to be generated.
00077     \return The number of samples actually generated.
00078 */
00079 int t31_tx(t31_state_t *s, int16_t amp[], int max_len);
00080 
00081 int t31_t38_send_timeout(t31_state_t *s, int samples);
00082 
00083 /*! Select whether silent audio will be sent when transmit is idle.
00084     \brief Select whether silent audio will be sent when transmit is idle.
00085     \param s The T.31 modem context.
00086     \param transmit_on_idle TRUE if silent audio should be output when the transmitter is
00087            idle. FALSE to transmit zero length audio when the transmitter is idle. The default
00088            behaviour is FALSE.
00089 */
00090 void t31_set_transmit_on_idle(t31_state_t *s, int transmit_on_idle);
00091 
00092 /*! Select whether TEP mode will be used (or time allowed for it (when transmitting).
00093     \brief Select whether TEP mode will be used.
00094     \param s The T.31 modem context.
00095     \param use_tep TRUE if TEP is to be ised.
00096 */
00097 void t31_set_tep_mode(t31_state_t *s, int use_tep);
00098 
00099 /*! Select whether T.38 data will be paced as it is transmitted.
00100     \brief Select whether T.38 data will be paced.
00101     \param s The T.31 modem context.
00102     \param without_pacing TRUE if data is to be sent as fast as possible. FALSE if it is
00103            to be paced.
00104 */
00105 void t31_set_t38_config(t31_state_t *s, int without_pacing);
00106 
00107 /*! Get a pointer to the logging context associated with a T.31 context.
00108     \brief Get a pointer to the logging context associated with a T.31 context.
00109     \param s The T.31 context.
00110     \return A pointer to the logging context, or NULL.
00111 */
00112 logging_state_t *t31_get_logging_state(t31_state_t *s);
00113 
00114 /*! Initialise a T.31 context. This must be called before the first
00115     use of the context, to initialise its contents.
00116     \brief Initialise a T.31 context.
00117     \param s The T.31 context.
00118     \param at_tx_handler A callback routine to handle AT interpreter channel output.
00119     \param at_tx_user_data An opaque pointer passed in called to at_tx_handler.
00120     \param modem_control_handler A callback routine to handle control of the modem (off-hook, etc).
00121     \param modem_control_user_data An opaque pointer passed in called to modem_control_handler.
00122     \param tx_t38_packet_handler ???
00123     \param tx_t38_packet_user_data ???
00124     \return A pointer to the T.31 context. */
00125 t31_state_t *t31_init(t31_state_t *s,
00126                       at_tx_handler_t *at_tx_handler,
00127                       void *at_tx_user_data,
00128                       t31_modem_control_handler_t *modem_control_handler,
00129                       void *modem_control_user_data,
00130                       t38_tx_packet_handler_t *tx_t38_packet_handler,
00131                       void *tx_t38_packet_user_data);
00132 
00133 /*! Release a T.31 context.
00134     \brief Release a T.31 context.
00135     \param s The T.31 context.
00136     \return 0 for OK */
00137 int t31_release(t31_state_t *s);
00138 
00139 #if defined(__cplusplus)
00140 }
00141 #endif
00142 
00143 #endif
00144 /*- End of file ------------------------------------------------------------*/

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