From 5da86a52903cf76faea421421e0257ed32564e92 Mon Sep 17 00:00:00 2001
From: Mark Spencer <markster@digium.com>
Date: Sat, 10 Nov 2001 20:31:39 +0000
Subject: [PATCH] Version 0.1.10 from FTP
git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@388 65c4cc65-6c06-0410-ace0-fbb531ad65f3
---
channels/gentone-ulaw.c | 157 ++++++++++++++++++++++++
channels/gentone.c | 4 +-
ecdisa.h | 15 +++
fskmodem.c | 13 +-
include/asterisk/frame.h | 250 +++++++++++++++++++++++++++------------
include/asterisk/tdd.h | 74 ++++++++++++
6 files changed, 434 insertions(+), 79 deletions(-)
create mode 100755 channels/gentone-ulaw.c
create mode 100755 ecdisa.h
create mode 100755 include/asterisk/tdd.h
diff --git a/channels/gentone-ulaw.c b/channels/gentone-ulaw.c
new file mode 100755
index 0000000000..b290d76c7a
--- /dev/null
+++ b/channels/gentone-ulaw.c
@@ -0,0 +1,157 @@
+/* Generate a header file for a particular
+ single or double frequency */
+
+#include <stdio.h>
+#include <math.h>
+#include <string.h>
+#include <unistd.h>
+#include <stdlib.h>
+#define CLIP 32635
+#define BIAS 0x84
+static float loudness=16384.0;
+
+static int calc_samples(int freq)
+{
+ int x, samples;
+ /* Calculate the number of samples at 8000hz sampling
+ we need to have this wave form */
+ samples = 8000;
+ /* Take out common 2's up to six times */
+ for (x=0;x<6;x++)
+ if (!(freq % 2)) {
+ freq /= 2;
+ samples /= 2;
+ }
+ /* Take out common 5's (up to three times */
+ for (x=0;x<3;x++)
+ if (!(freq % 5)) {
+ freq /= 5;
+ samples /=5;
+ }
+ /* No more common factors. */
+ return samples;
+}
+
+/*
+** This routine converts from linear to ulaw
+**
+** Craig Reese: IDA/Supercomputing Research Center
+** Joe Campbell: Department of Defense
+** 29 September 1989
+**
+** References:
+** 1) CCITT Recommendation G.711 (very difficult to follow)
+** 2) "A New Digital Technique for Implementation of Any
+** Continuous PCM Companding Law," Villeret, Michel,
+** et al. 1973 IEEE Int. Conf. on Communications, Vol 1,
+** 1973, pg. 11.12-11.17
+** 3) MIL-STD-188-113,"Interoperability and Performance Standards
+** for Analog-to_Digital Conversion Techniques,"
+** 17 February 1987
+**
+** Input: Signed 16 bit linear sample
+** Output: 8 bit ulaw sample
+*/
+
+#define ZEROTRAP /* turn on the trap as per the MIL-STD */
+#define BIAS 0x84 /* define the add-in bias for 16 bit samples */
+#define CLIP 32635
+
+static unsigned char linear2ulaw(short sample) {
+static int exp_lut[256] = {0,0,1,1,2,2,2,2,3,3,3,3,3,3,3,3,
+ 4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,
+ 5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,
+ 5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,
+ 6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,
+ 6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,
+ 6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,
+ 6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,
+ 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
+ 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
+ 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
+ 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
+ 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
+ 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
+ 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
+ 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7};
+ int sign, exponent, mantissa;
+ unsigned char ulawbyte;
+
+ /* Get the sample into sign-magnitude. */
+ sign = (sample >> 8) & 0x80; /* set aside the sign */
+ if (sign != 0) sample = -sample; /* get magnitude */
+ if (sample > CLIP) sample = CLIP; /* clip the magnitude */
+
+ /* Convert from 16 bit linear to ulaw. */
+ sample = sample + BIAS;
+ exponent = exp_lut[(sample >> 7) & 0xFF];
+ mantissa = (sample >> (exponent + 3)) & 0x0F;
+ ulawbyte = ~(sign | (exponent << 4) | mantissa);
+#ifdef ZEROTRAP
+ if (ulawbyte == 0) ulawbyte = 0x02; /* optional CCITT trap */
+#endif
+
+ return(ulawbyte);
+}
+
+int main(int argc, char *argv[])
+{
+ FILE *f;
+ int freq1, freq2;
+ float wlen1, wlen2;
+ float val;
+ int x, samples1, samples2, samples=0;
+ char fn[256];
+ if (argc < 3) {
+ fprintf(stderr, "Usage: gensound <name> <freq1> [freq2]\n");
+ exit(1);
+ }
+ freq1 = atoi(argv[2]);
+ if (argc > 3)
+ freq2 = atoi(argv[3]);
+ else
+ freq2 = 0;
+ wlen1 = 8000.0/(float)freq1;
+ samples1 = calc_samples(freq1);
+ printf("Wavelength 1 (in samples): %10.5f\n", wlen1);
+ printf("Minimum samples (1): %d (%f.3 wavelengths)\n", samples1, samples1 / wlen1);
+ if (freq2) {
+ wlen2 = 8000.0/(float)freq2;
+ samples2 = calc_samples(freq2);
+ printf("Wavelength 1 (in samples): %10.5f\n", wlen2);
+ printf("Minimum samples (1): %d (%f.3 wavelengths)\n", samples2, samples2 / wlen2);
+ }
+ samples = samples1;
+ if (freq2) {
+ while(samples % samples2)
+ samples += samples1;
+ }
+ printf("Need %d samples\n", samples);
+ snprintf(fn, sizeof(fn), "%s.h", argv[1]);
+ if ((f = fopen(fn, "w"))) {
+ if (freq2)
+ fprintf(f, "/* %s: Generated from frequencies %d and %d \n"
+ " by gentone. %d samples */\n", fn, freq1, freq2, samples);
+ else
+ fprintf(f, "/* %s: Generated from frequency %d\n"
+ " by gentone. %d samples */\n", fn, freq1, samples);
+ fprintf(f, "static unsigned char %s[%d] = {\n\t", argv[1], samples);
+ for (x=0;x<samples;x++) {
+ val = loudness * sin((freq1 * 2.0 * M_PI * x)/8000.0);
+ if (freq2)
+ val += loudness * sin((freq2 * 2.0 * M_PI * x)/8000.0);
+ fprintf(f, "%3d, ", (int) linear2ulaw(val));
+ if (!((x+1) % 8))
+ fprintf(f, "\n\t");
+ }
+ if (x % 15)
+ fprintf(f, "\n");
+ fprintf(f, "};\n");
+ fclose(f);
+ printf("Wrote %s\n", fn);
+ } else {
+ fprintf(stderr, "Unable to open %s for writing\n", fn);
+ return 1;
+ }
+ return 0;
+}
diff --git a/channels/gentone.c b/channels/gentone.c
index 00f5af1794..530db0eefa 100755
--- a/channels/gentone.c
+++ b/channels/gentone.c
@@ -69,10 +69,10 @@ int main(int argc, char *argv[])
if ((f = fopen(fn, "w"))) {
if (freq2)
fprintf(f, "/* %s: Generated from frequencies %d and %d \n"
- " by gensound. %d samples */\n", fn, freq1, freq2, samples);
+ " by gentone. %d samples */\n", fn, freq1, freq2, samples);
else
fprintf(f, "/* %s: Generated from frequency %d\n"
- " by gensound. %d samples */\n", fn, freq1, samples);
+ " by gentone. %d samples */\n", fn, freq1, samples);
fprintf(f, "static short %s[%d] = {\n\t", argv[1], samples);
for (x=0;x<samples;x++) {
val = loudness * sin((freq1 * 2.0 * M_PI * x)/8000.0);
diff --git a/ecdisa.h b/ecdisa.h
new file mode 100755
index 0000000000..df6f773a09
--- /dev/null
+++ b/ecdisa.h
@@ -0,0 +1,15 @@
+/* ecdisa.h: Generated from frequency 2100
+ by gentone. 80 samples */
+static unsigned char ecdisa[80] = {
+ 255, 143, 58, 16, 171, 146, 34, 20,
+ 156, 151, 25, 26, 149, 159, 19, 38,
+ 145, 177, 16, 73, 143, 73, 16, 177,
+ 145, 38, 19, 159, 149, 26, 25, 151,
+ 156, 20, 34, 146, 171, 16, 58, 143,
+ 255, 15, 186, 144, 43, 18, 162, 148,
+ 28, 23, 153, 154, 21, 31, 147, 166,
+ 17, 49, 144, 201, 15, 201, 144, 49,
+ 17, 166, 147, 31, 21, 154, 153, 23,
+ 28, 148, 162, 18, 43, 144, 186, 15,
+
+};
diff --git a/fskmodem.c b/fskmodem.c
index 554bb94109..6d45bde7e7 100755
--- a/fskmodem.c
+++ b/fskmodem.c
@@ -234,10 +234,15 @@ search_startbit3:
getbyte:
- /* Need at least 80 samples to be sure we'll have a byte */
- if (*len < 80)
- return 0;
-
+ /* Need at least 80 samples (for 1200) or
+ 1320 (for 45.5) to be sure we'll have a byte */
+ if (fskd->nbit < 8) {
+ if (*len < 1320)
+ return 0;
+ } else {
+ if (*len < 80)
+ return 0;
+ }
/* Leemos ahora los bits de datos */
j=fskd->nbit;
for (a=n1=0;j;j--) {
diff --git a/include/asterisk/frame.h b/include/asterisk/frame.h
index 536f83c040..44e1c3073a 100755
--- a/include/asterisk/frame.h
+++ b/include/asterisk/frame.h
@@ -23,20 +23,30 @@ extern "C" {
#include <endian.h>
#include <sys/types.h>
+//! Data structure associated with a single frame of data
/* A frame of data read used to communicate between
between channels and applications */
struct ast_frame {
- int frametype; /* Kind of frame */
- int subclass; /* Subclass, frame dependent */
- int datalen; /* Length of data */
- int timelen; /* Amount of time associated with this frame */
- int mallocd; /* Was the data malloc'd? i.e. should we
- free it when we discard the frame? */
- int offset; /* How far into "data" the data really starts */
- char *src; /* Optional source of frame for debugging */
- void *data; /* Pointer to actual data */
- struct ast_frame *prev; /* Next/Prev for linking stand alone frames */
- struct ast_frame *next; /* Next/Prev for linking stand alone frames */
+ /*! Kind of frame */
+ int frametype;
+ /*! Subclass, frame dependent */
+ int subclass;
+ /*! Length of data */
+ int datalen;
+ /*! Amount of time associated with this frame */
+ int timelen;
+ /*! Was the data malloc'd? i.e. should we free it when we discard the frame? */
+ int mallocd;
+ /*! How far into "data" the data really starts */
+ int offset;
+ /*! Optional source of frame for debugging */
+ char *src;
+ /*! Pointer to actual data */
+ void *data;
+ /*! Next/Prev for linking stand alone frames */
+ struct ast_frame *prev;
+ /*! Next/Prev for linking stand alone frames */
+ struct ast_frame *next;
/* Unused except if debugging is turned on, but left
in the struct so that it can be turned on without
requiring a recompile of the whole thing */
@@ -48,63 +58,109 @@ struct ast_frame_chain {
struct ast_frame_chain *next;
};
-#define AST_FRIENDLY_OFFSET 64 /* It's polite for a a new frame to
+#define AST_FRIENDLY_OFFSET 64 /*! It's polite for a a new frame to
have at least this number of bytes
of offset before your real frame data
so that additional headers can be
added. */
-
-#define AST_MALLOCD_HDR (1 << 0) /* Need the header be free'd? */
-#define AST_MALLOCD_DATA (1 << 1) /* Need the data be free'd? */
-#define AST_MALLOCD_SRC (1 << 2) /* Need the source be free'd? (haha!) */
+/*! Need the header be free'd? */
+#define AST_MALLOCD_HDR (1 << 0)
+/*! Need the data be free'd? */
+#define AST_MALLOCD_DATA (1 << 1)
+/*! Need the source be free'd? (haha!) */
+#define AST_MALLOCD_SRC (1 << 2)
/* Frame types */
-#define AST_FRAME_DTMF 1 /* A DTMF digit, subclass is the digit */
-#define AST_FRAME_VOICE 2 /* Voice data, subclass is AST_FORMAT_* */
-#define AST_FRAME_VIDEO 3 /* Video frame, maybe?? :) */
-#define AST_FRAME_CONTROL 4 /* A control frame, subclass is AST_CONTROL_* */
-#define AST_FRAME_NULL 5 /* An empty, useless frame */
-#define AST_FRAME_IAX 6 /* Inter Aterisk Exchange private frame type */
-#define AST_FRAME_TEXT 7 /* Text messages */
-#define AST_FRAME_IMAGE 8 /* Image Frames */
-#define AST_FRAME_HTML 9 /* HTML Frame */
+/*! A DTMF digit, subclass is the digit */
+#define AST_FRAME_DTMF 1
+/*! Voice data, subclass is AST_FORMAT_* */
+#define AST_FRAME_VOICE 2
+/*! Video frame, maybe?? :) */
+#define AST_FRAME_VIDEO 3
+/*! A control frame, subclass is AST_CONTROL_* */
+#define AST_FRAME_CONTROL 4
+/*! An empty, useless frame */
+#define AST_FRAME_NULL 5
+/*! Inter Aterisk Exchange private frame type */
+#define AST_FRAME_IAX 6
+/*! Text messages */
+#define AST_FRAME_TEXT 7
+/*! Image Frames */
+#define AST_FRAME_IMAGE 8
+/*! HTML Frame */
+#define AST_FRAME_HTML 9
/* HTML subclasses */
-#define AST_HTML_URL 1 /* Sending a URL */
-#define AST_HTML_DATA 2 /* Data frame */
-#define AST_HTML_BEGIN 4 /* Beginning frame */
-#define AST_HTML_END 8 /* End frame */
-#define AST_HTML_LDCOMPLETE 16 /* Load is complete */
-#define AST_HTML_NOSUPPORT 17 /* Peer is unable to support HTML */
-#define AST_HTML_LINKURL 18 /* Send URL, and track */
+/*! Sending a URL */
+#define AST_HTML_URL 1
+/*! Data frame */
+#define AST_HTML_DATA 2
+/*! Beginning frame */
+#define AST_HTML_BEGIN 4
+/*! End frame */
+#define AST_HTML_END 8
+/*! Load is complete */
+#define AST_HTML_LDCOMPLETE 16
+/*! Peer is unable to support HTML */
+#define AST_HTML_NOSUPPORT 17
+/*! Send URL, and track */
+#define AST_HTML_LINKURL 18
+/*! No more HTML linkage */
+#define AST_HTML_UNLINK 19
+/*! Reject link request */
+#define AST_HTML_LINKREJECT 20
/* Data formats for capabilities and frames alike */
-#define AST_FORMAT_G723_1 (1 << 0) /* G.723.1 compression */
-#define AST_FORMAT_GSM (1 << 1) /* GSM compression */
-#define AST_FORMAT_ULAW (1 << 2) /* Raw mu-law data (G.711) */
-#define AST_FORMAT_ALAW (1 << 3) /* Raw A-law data (G.711) */
-#define AST_FORMAT_MP3 (1 << 4) /* MPEG-2 layer 3 */
-#define AST_FORMAT_ADPCM (1 << 5) /* ADPCM (whose?) */
-#define AST_FORMAT_SLINEAR (1 << 6) /* Raw 16-bit Signed Linear (8000 Hz) PCM */
-#define AST_FORMAT_LPC10 (1 << 7) /* LPC10, 180 samples/frame */
-#define AST_FORMAT_MAX_AUDIO (1 << 15) /* Maximum audio format */
-#define AST_FORMAT_JPEG (1 << 16) /* JPEG Images */
-#define AST_FORMAT_PNG (1 << 17) /* PNG Images */
-#define AST_FORMAT_H261 (1 << 18) /* H.261 Video */
-#define AST_FORMAT_H263 (1 << 19) /* H.263 Video */
+/*! G.723.1 compression */
+#define AST_FORMAT_G723_1 (1 << 0)
+/*! GSM compression */
+#define AST_FORMAT_GSM (1 << 1)
+/*! Raw mu-law data (G.711) */
+#define AST_FORMAT_ULAW (1 << 2)
+/*! Raw A-law data (G.711) */
+#define AST_FORMAT_ALAW (1 << 3)
+/*! MPEG-2 layer 3 */
+#define AST_FORMAT_MP3 (1 << 4)
+/*! ADPCM (whose?) */
+#define AST_FORMAT_ADPCM (1 << 5)
+/*! Raw 16-bit Signed Linear (8000 Hz) PCM */
+#define AST_FORMAT_SLINEAR (1 << 6)
+/*! LPC10, 180 samples/frame */
+#define AST_FORMAT_LPC10 (1 << 7)
+/*! Maximum audio format */
+#define AST_FORMAT_MAX_AUDIO (1 << 15)
+/*! JPEG Images */
+#define AST_FORMAT_JPEG (1 << 16)
+/*! PNG Images */
+#define AST_FORMAT_PNG (1 << 17)
+/*! H.261 Video */
+#define AST_FORMAT_H261 (1 << 18)
+/*! H.263 Video */
+#define AST_FORMAT_H263 (1 << 19)
/* Control frame types */
-#define AST_CONTROL_HANGUP 1 /* Other end has hungup */
-#define AST_CONTROL_RING 2 /* Local ring */
-#define AST_CONTROL_RINGING 3 /* Remote end is ringing */
-#define AST_CONTROL_ANSWER 4 /* Remote end has answered */
-#define AST_CONTROL_BUSY 5 /* Remote end is busy */
-#define AST_CONTROL_TAKEOFFHOOK 6 /* Make it go off hook */
-#define AST_CONTROL_OFFHOOK 7 /* Line is off hook */
-#define AST_CONTROL_CONGESTION 8 /* Congestion (circuits busy) */
-#define AST_CONTROL_FLASH 9 /* Flash hook */
-#define AST_CONTROL_WINK 10 /* Wink */
-#define AST_CONTROL_OPTION 11 /* Set a low-level option */
+/*! Other end has hungup */
+#define AST_CONTROL_HANGUP 1
+/*! Local ring */
+#define AST_CONTROL_RING 2
+/*! Remote end is ringing */
+#define AST_CONTROL_RINGING 3
+/*! Remote end has answered */
+#define AST_CONTROL_ANSWER 4
+/*! Remote end is busy */
+#define AST_CONTROL_BUSY 5
+/*! Make it go off hook */
+#define AST_CONTROL_TAKEOFFHOOK 6
+/*! Line is off hook */
+#define AST_CONTROL_OFFHOOK 7
+/*! Congestion (circuits busy) */
+#define AST_CONTROL_CONGESTION 8
+/*! Flash hook */
+#define AST_CONTROL_FLASH 9
+/*! Wink */
+#define AST_CONTROL_WINK 10
+/*! Set a low-level option */
+#define AST_CONTROL_OPTION 11
/* Option identifiers and flags */
#define AST_OPTION_FLAG_REQUEST 0
@@ -112,11 +168,14 @@ struct ast_frame_chain {
#define AST_OPTION_FLAG_REJECT 2
#define AST_OPTION_FLAG_QUERY 4
#define AST_OPTION_FLAG_ANSWER 5
-#define AST_OPTION_FLAG_WTF 6
+#define AST_OPTION_FLAG_WTF 6
+
+/* Verify touchtones by muting audio transmission
+ (and reception) and verify the tone is still present */
+#define AST_OPTION_TONE_VERIFY 1
-#define AST_OPTION_TONE_VERIFY 1 /* Verify touchtones by muting audio
- transmission (and reception) and
- verify the tone is still present */
+/* Put a compatible channel into TDD (TTY for the hearing-impared) mode */
+#define AST_OPTION_TDD 2
struct ast_option_header {
/* Always keep in network byte order */
@@ -134,37 +193,82 @@ struct ast_option_header {
u_int8_t data[0];
};
-/* Request a frame be allocated. source is an optional source of the frame,
- len is the requested length, or "0" if the caller will supply the buffer */
+// Requests a frame to be allocated
+/*
+ * \param source
+ * Request a frame be allocated. source is an optional source of the frame,
+ * len is the requested length, or "0" if the caller will supply the buffer
+ */
+#if 0 /* Unimplemented */
struct ast_frame *ast_fralloc(char *source, int len);
+#endif
-/* Free a frame, and the memory it used if applicable */
+//! Frees a frame
+/*!
+ * \param fr Frame to free
+ * Free a frame, and the memory it used if applicable
+ * no return.
+ */
void ast_frfree(struct ast_frame *fr);
-/* Take a frame, and if it's not been malloc'd, make a malloc'd copy
- and if the data hasn't been malloced then make the
- data malloc'd. If you need to store frames, say for queueing, then
- you should call this function. */
+//! Copies a frame
+/*!
+ * \param fr frame to act upon
+ * Take a frame, and if it's not been malloc'd, make a malloc'd copy
+ * and if the data hasn't been malloced then make the
+ * data malloc'd. If you need to store frames, say for queueing, then
+ * you should call this function.
+ * Returns a frame on success, NULL on error
+ */
struct ast_frame *ast_frisolate(struct ast_frame *fr);
-/* Dupliates a frame -- should only rarely be used, typically frisolate is
- good enough */
+//! Copies a frame
+/*!
+ * \param fr frame to copy
+ * Dupliates a frame -- should only rarely be used, typically frisolate is good enough
+ * Returns a frame on success, NULL on error
+ */
struct ast_frame *ast_frdup(struct ast_frame *fr);
+//! Chains a frame -- unimplemented
+#if 0 /* unimplemented */
void ast_frchain(struct ast_frame_chain *fc);
+#endif
-/* Read a frame from a stream or packet fd, as written by fd_write */
+//! Reads a frame from an fd
+/*!
+ * \param fd an opened fd to read from
+ * Read a frame from a stream or packet fd, as written by fd_write
+ * returns a frame on success, NULL on error
+ */
struct ast_frame *ast_fr_fdread(int fd);
-/* Write a frame to an fd */
+//! Writes a frame to an fd
+/*!
+ * \param fd Which fd to write to
+ * \param frame frame to write to the fd
+ * Write a frame to an fd
+ * Returns 0 on success, -1 on failure
+ */
int ast_fr_fdwrite(int fd, struct ast_frame *frame);
-/* Send a hangup (NULL equivalent) on an fd */
+//! Sends a hangup to an fd
+/*!
+ * \param fd fd to write to
+ * Send a hangup (NULL equivalent) on an fd
+ * Returns 0 on success, -1 on failure
+ */
int ast_fr_fdhangup(int fd);
-/* Get a format by its name */
+//! Get a format from a name
+/*!
+ * \param name string of format
+ * Gets a format from a name.
+ * This returns the form of the format in binary on success, 0 on error.
+ */
extern int ast_getformatbyname(char *name);
+//! Pick the best codec
/* Choose the best codec... Uhhh... Yah. */
extern int ast_best_codec(int fmts);
diff --git a/include/asterisk/tdd.h b/include/asterisk/tdd.h
new file mode 100755
index 0000000000..4ee057f974
--- /dev/null
+++ b/include/asterisk/tdd.h
@@ -0,0 +1,74 @@
+/*
+ * Asterisk -- A telephony toolkit for Linux.
+ *
+ * TTY/TDD Generation support
+ *
+ * Copyright (C) 1999, Mark Spencer
+ *
+ * Mark Spencer <markster@linux-support.net>
+ *
+ * This program is free software, distributed under the terms of
+ * the GNU General Public License.
+ *
+ * Includes code and algorithms from the Zapata library.
+ *
+ */
+
+#ifndef _TDD_H
+#define _TDD_H
+
+#define TDD_BYTES_PER_CHAR 2700
+
+struct tdd_state;
+typedef struct tdd_state TDDSTATE;
+
+//! CallerID Initialization
+/*!
+ * Initializes the TDD system. Mostly stuff for inverse FFT
+ */
+extern void tdd_init(void);
+
+//! Generates a CallerID FSK stream in ulaw format suitable for transmission.
+/*!
+ * \param buf Buffer to use. This needs to be large enough to accomodate all the generated samples.
+ * \param string This is the string to send.
+ * This function creates a stream of TDD data in ulaw format. It returns the size
+ * (in bytes) of the data (if it returns a size of 0, there is probably an error)
+*/
+extern int tdd_generate(struct tdd_state *tdd, unsigned char *buf, char *string);
+
+//! Create a TDD state machine
+/*!
+ * This function returns a malloc'd instance of the tdd_state data structure.
+ * Returns a pointer to a malloc'd tdd_state structure, or NULL on error.
+ */
+extern struct tdd_state *tdd_new(void);
+
+//! Read samples into the state machine, and return character (if any).
+/*!
+ * \param tdd Which state machine to act upon
+ * \param buffer containing your samples
+ * \param samples number of samples contained within the buffer.
+ *
+ * Send received audio to the TDD demodulator.
+ * Returns -1 on error, 0 for "needs more samples",
+ * and > 0 (the character) if reception of a character is complete.
+ */
+extern int tdd_feed(struct tdd_state *tdd, unsigned char *ubuf, int samples);
+
+//! Free a TDD state machine
+/*!
+ * \param tdd This is the tdd_state state machine to free
+ * This function frees tdd_state tdd.
+ */
+extern void tdd_free(struct tdd_state *tdd);
+
+//! Generate Echo Canceller diable tone (2100HZ)
+/*!
+ * \param outbuf This is the buffer to receive the tone data
+ * \param len This is the length (in samples) of the tone data to generate
+ * Returns 0 if no error, and -1 if error.
+ */
+extern int ast_tdd_gen_ecdisa(unsigned char *outbuf, int len);
+
+#endif
--
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