# initially adapted from https://github.com/saizai/wumpusphone/blob/master/asterisk-1.8.0.patch#L251
# less invastive version from https://github.com/hharte/1dcoinctrl/blob/master/asterisk/main/dsp.c-patch
# updated for asterisk 20.2.0

--- main/dsp.c.orig	Mon Apr 10 11:39:45 2023
+++ main/dsp.c	Mon Apr 10 11:43:18 2023
@@ -165,7 +165,7 @@
 
 #define	MAX_DTMF_DIGITS		128
 
-#define DTMF_MATRIX_SIZE	4
+#define DTMF_MATRIX_SIZE	5
 
 /* Basic DTMF (AT&T) specs:
  *
@@ -317,15 +317,15 @@
 } digit_detect_state_t;
 
 static const float dtmf_row[] = {
-	697.0,  770.0,  852.0,  941.0
+	697.0,  770.0,  852.0,  941.0,	1700.0,
 };
 static const float dtmf_col[] = {
-	1209.0, 1336.0, 1477.0, 1633.0
+	1209.0, 1336.0, 1477.0, 1633.0,	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 dtmf_positions[] = "123A-" "456B-" "789C-" "*0#D-" "----$";
 static const char bell_mf_positions[] = "1247C-358A--69*---0B----#";
 static int thresholds[THRESHOLD_MAX];
 static float dtmf_normal_twist;		/* AT&T = 8dB */
@@ -734,6 +734,8 @@
 			goertzel_sample(s->td.dtmf.col_out + 2, samp);
 			goertzel_sample(s->td.dtmf.row_out + 3, samp);
 			goertzel_sample(s->td.dtmf.col_out + 3, samp);
+			goertzel_sample(s->td.dtmf.row_out + 4, samp);
+			goertzel_sample(s->td.dtmf.col_out + 4, samp);
 			/* go up to DTMF_MATRIX_SIZE - 1 */
 		}
 		s->td.dtmf.current_sample += (limit - sample);
@@ -776,9 +778,9 @@
 			}
 			/* ... and fraction of total energy test */
 			if (i >= DTMF_MATRIX_SIZE &&
-			    (row_energy[best_row] + col_energy[best_col]) > DTMF_TO_TOTAL_ENERGY * s->td.dtmf.energy) {
+			    (row_energy[best_row] + col_energy[best_col]) > (DTMF_TO_TOTAL_ENERGY / (relax ? 2 : 1)) * s->td.dtmf.energy) {
 				/* Got a hit */
-				hit = dtmf_positions[(best_row << 2) + best_col];
+				hit = dtmf_positions[(best_row * DTMF_MATRIX_SIZE) + best_col];
 				ast_debug(10, "DTMF hit '%c'\n", hit);
 			}
 		}