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git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@388 65c4cc65-6c06-0410-ace0-fbb531ad65f3
75 lines
2.2 KiB
C
Executable File
75 lines
2.2 KiB
C
Executable File
/*
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* Asterisk -- A telephony toolkit for Linux.
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*
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* TTY/TDD Generation support
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*
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* Copyright (C) 1999, Mark Spencer
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*
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* Mark Spencer <markster@linux-support.net>
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*
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* This program is free software, distributed under the terms of
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* the GNU General Public License.
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*
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* Includes code and algorithms from the Zapata library.
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*
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*/
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#ifndef _TDD_H
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#define _TDD_H
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#define TDD_BYTES_PER_CHAR 2700
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struct tdd_state;
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typedef struct tdd_state TDDSTATE;
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//! CallerID Initialization
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/*!
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* Initializes the TDD system. Mostly stuff for inverse FFT
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*/
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extern void tdd_init(void);
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//! Generates a CallerID FSK stream in ulaw format suitable for transmission.
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/*!
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* \param buf Buffer to use. This needs to be large enough to accomodate all the generated samples.
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* \param string This is the string to send.
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* This function creates a stream of TDD data in ulaw format. It returns the size
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* (in bytes) of the data (if it returns a size of 0, there is probably an error)
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*/
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extern int tdd_generate(struct tdd_state *tdd, unsigned char *buf, char *string);
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//! Create a TDD state machine
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/*!
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* This function returns a malloc'd instance of the tdd_state data structure.
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* Returns a pointer to a malloc'd tdd_state structure, or NULL on error.
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*/
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extern struct tdd_state *tdd_new(void);
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//! Read samples into the state machine, and return character (if any).
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/*!
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* \param tdd Which state machine to act upon
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* \param buffer containing your samples
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* \param samples number of samples contained within the buffer.
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*
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* Send received audio to the TDD demodulator.
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* Returns -1 on error, 0 for "needs more samples",
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* and > 0 (the character) if reception of a character is complete.
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*/
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extern int tdd_feed(struct tdd_state *tdd, unsigned char *ubuf, int samples);
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//! Free a TDD state machine
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/*!
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* \param tdd This is the tdd_state state machine to free
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* This function frees tdd_state tdd.
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*/
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extern void tdd_free(struct tdd_state *tdd);
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//! Generate Echo Canceller diable tone (2100HZ)
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/*!
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* \param outbuf This is the buffer to receive the tone data
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* \param len This is the length (in samples) of the tone data to generate
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* Returns 0 if no error, and -1 if error.
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*/
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extern int ast_tdd_gen_ecdisa(unsigned char *outbuf, int len);
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#endif
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