patch for Asterisk to recognise coin tones like DTMF tones (it calls …

…them $)
saizai · Nov 18, 2010 · c55b299 · c55b299
1 parent 006836d
commit c55b299
Showing 1 changed file with 117 additions and 0 deletions.
diff --git a/asterisk-1.8.0-coins.diff b/asterisk-1.8.0-coins.diff
@@ -0,0 +1,117 @@
+diff -Naur asterisk-1.8.0/main/dsp.c asterisk-1.8.0-coins/main/dsp.c
+--- asterisk-1.8.0/main/dsp.c	2010-06-07 13:34:45.000000000 -0400
++++ asterisk-1.8.0-coins/main/dsp.c	2010-11-18 00:31:26.000000000 -0500
+@@ -19,6 +19,15 @@
+  * at the top of the source tree.
+  */
+
++/*
++ * This version is klugishly modified by Alex Fink, 2010, to recognise
++ * the US 1700 & 2200 Hz coin tone as if it were a DTMF tone.
++ *
++ * Various things below suggest that a 33ms tone with 33ms separations 
++ * might be too short to be recognised, but it seems to work okay.
++ * Does DTMF_GSIZE matter?
++ */
++
+ /*! \file
+  *
+  * \brief Convenience Signal Processing routines
+@@ -156,6 +165,7 @@
+
+ #define DTMF_THRESHOLD		8.0e7
+ #define FAX_THRESHOLD		8.0e7
++#define COIN_THRESHOLD		8.0e7
+ #define FAX_2ND_HARMONIC	2.0     /* 4dB */
+ #define DTMF_NORMAL_TWIST	6.3     /* 8dB */
+ #ifdef	RADIO_RELAX
+@@ -168,6 +178,7 @@
+ #define DTMF_2ND_HARMONIC_ROW       (relax ? 1.7 : 2.5)     /* 4dB normal */
+ #define DTMF_2ND_HARMONIC_COL	63.1    /* 18dB */
+ #define DTMF_TO_TOTAL_ENERGY	42.0
++#define COIN_TO_TOTAL_ENERGY	42.0
+
+ #define BELL_MF_THRESHOLD	1.6e9
+ #define BELL_MF_TWIST		4.0     /* 6dB */
+@@ -256,6 +267,8 @@
+ {
+ 	goertzel_state_t row_out[4];
+ 	goertzel_state_t col_out[4];
++	goertzel_state_t coin_low_out;
++	goertzel_state_t coin_high_out;
+ 	int hits_to_begin;		/* How many successive hits needed to consider begin of a digit */
+ 	int misses_to_end;		/* How many successive misses needed to consider end of a digit */
+ 	int hits;			/* How many successive hits we have seen already */
+@@ -296,10 +309,13 @@
+ static const float dtmf_col[] = {
+ 	1209.0, 1336.0, 1477.0, 1633.0
+ };
++static const float coin_low = 1700.0;
++static const float coin_high = 2200.0;
+ static const float mf_tones[] = {
+ 	700.0, 900.0, 1100.0, 1300.0, 1500.0, 1700.0
+ };
+ static const char dtmf_positions[] = "123A" "456B" "789C" "*0#D";
++static const char coin_char = '$';
+ static const char bell_mf_positions[] = "1247C-358A--69*---0B----#";
+ static int thresholds[THRESHOLD_MAX];
+
+@@ -488,6 +504,8 @@
+ 		goertzel_init(&s->col_out[i], dtmf_col[i], DTMF_GSIZE);
+ 		s->energy = 0.0;
+ 	}
++  goertzel_init(&s->coin_low_out, coin_low, DTMF_GSIZE);
++  goertzel_init(&s->coin_high_out, coin_high, DTMF_GSIZE);  
+ 	s->current_sample = 0;
+ 	s->hits = 0;
+ 	s->misses = 0;
+@@ -642,6 +660,8 @@
+ {
+ 	float row_energy[4];
+ 	float col_energy[4];
++  float coin_low_energy;
++  float coin_high_energy;
+ 	float famp;
+ 	int i;
+ 	int j;
+@@ -680,6 +700,8 @@
+ 			goertzel_sample(s->td.dtmf.col_out + 2, amp[j]);
+ 			goertzel_sample(s->td.dtmf.row_out + 3, amp[j]);
+ 			goertzel_sample(s->td.dtmf.col_out + 3, amp[j]);
++			goertzel_sample(&s->td.dtmf.coin_low_out, amp[j]);
++			goertzel_sample(&s->td.dtmf.coin_high_out, amp[j]);
+ 		}
+ 		s->td.dtmf.current_sample += (limit - sample);
+ 		if (s->td.dtmf.current_sample < DTMF_GSIZE) {
+@@ -701,6 +723,22 @@
+ 			}
+ 		}
+ 		hit = 0;
++    /* Check for the coin: test if it's past threshold and 
++       it beats all the DTMF frequency peaks.  (No twist test.) */
++    coin_low_energy = goertzel_result (&s->td.dtmf.coin_low_out);
++    coin_high_energy = goertzel_result (&s->td.dtmf.coin_high_out);
++    if (coin_low_energy >= COIN_THRESHOLD &&
++        coin_high_energy >= COIN_THRESHOLD &&
++        coin_low_energy > row_energy[best_row] &&
++        coin_high_energy > row_energy[best_row] &&
++        coin_low_energy > col_energy[best_col] &&
++        coin_high_energy > col_energy[best_col]) {
++			/* fraction of total energy test */
++			if ((coin_low_energy + coin_high_energy) > COIN_TO_TOTAL_ENERGY * s->td.dtmf.energy) {
++				/* Got a hit */
++				hit = coin_char;
++			}
++    }
+ 		/* Basic signal level test and the twist test */
+ 		if (row_energy[best_row] >= DTMF_THRESHOLD && 
+ 		    col_energy[best_col] >= DTMF_THRESHOLD &&
+@@ -774,6 +812,8 @@
+ 			goertzel_reset(&s->td.dtmf.row_out[i]);
+ 			goertzel_reset(&s->td.dtmf.col_out[i]);
+ 		}
++    goertzel_reset(&s->td.dtmf.coin_low_out);
++    goertzel_reset(&s->td.dtmf.coin_high_out);
+ 		s->td.dtmf.energy = 0.0;
+ 		s->td.dtmf.current_sample = 0;
+ 	}