diff --git a/CHANGES b/CHANGES
index 6e3a49bda..3a4ca5ec6 100644
--- a/CHANGES
+++ b/CHANGES
@@ -28,6 +28,11 @@ Asterisk HTTP Server
 --------------------------
  * The HTTP Server can bind to IPv6 addresses.
 
+chan_dahdi
+--------------------------
+ * Busy tone patterns featuring 2 silence and 2 tone lengths can now be used
+   with busydetect.  usage example: busypattern=200,200,200,600
+
 CLI Changes
 --------------------------
  * New 'gtalk show settings' command showing the current settings loaded from
diff --git a/channels/chan_dahdi.c b/channels/chan_dahdi.c
index 39ecbfed6..1e10d4e94 100644
--- a/channels/chan_dahdi.c
+++ b/channels/chan_dahdi.c
@@ -1115,15 +1115,10 @@ struct dahdi_pvt {
 	 */
 	int busycount;
 	/*!
-	 * \brief Length of "busy" tone on time.
-	 * \note Set from the "busypattern" value read in from chan_dahdi.conf
+	 * \brief Busy cadence pattern description.
+	 * \note Set from the "busypattern" value read from chan_dahdi.conf
 	 */
-	int busy_tonelength;
-	/*!
-	 * \brief Length of "busy" tone off time.
-	 * \note Set from the "busypattern" value read in from chan_dahdi.conf
-	 */
-	int busy_quietlength;
+	struct ast_dsp_busy_pattern busy_cadence;
 	/*!
 	 * \brief Bitmapped call progress detection flags. CALLPROGRESS_xxx values.
 	 * \note Bits set from the "callprogress" and "faxdetect" values read in from chan_dahdi.conf
@@ -9542,7 +9537,7 @@ static struct ast_channel *dahdi_new(struct dahdi_pvt *i, int state, int startpb
 					ast_dsp_set_call_progress_zone(i->dsp, progzone);
 				if (i->busydetect && CANBUSYDETECT(i)) {
 					ast_dsp_set_busy_count(i->dsp, i->busycount);
-					ast_dsp_set_busy_pattern(i->dsp, i->busy_tonelength, i->busy_quietlength);
+					ast_dsp_set_busy_pattern(i->dsp, &i->busy_cadence);
 				}
 			}
 		}
@@ -12615,8 +12610,7 @@ static struct dahdi_pvt *mkintf(int channel, const struct dahdi_chan_conf *conf,
 		}
 		tmp->busydetect = conf->chan.busydetect;
 		tmp->busycount = conf->chan.busycount;
-		tmp->busy_tonelength = conf->chan.busy_tonelength;
-		tmp->busy_quietlength = conf->chan.busy_quietlength;
+		tmp->busy_cadence = conf->chan.busy_cadence;
 		tmp->callprogress = conf->chan.callprogress;
 		tmp->waitfordialtone = conf->chan.waitfordialtone;
 		tmp->cancallforward = conf->chan.cancallforward;
@@ -15120,7 +15114,7 @@ static char *dahdi_show_channel(struct ast_cli_entry *e, int cmd, struct ast_cli
 				ast_cli(a->fd, "    Busy Detector Debug: Enabled\n");
 #endif
 				ast_cli(a->fd, "    Busy Count: %d\n", tmp->busycount);
-				ast_cli(a->fd, "    Busy Pattern: %d,%d\n", tmp->busy_tonelength, tmp->busy_quietlength);
+				ast_cli(a->fd, "    Busy Pattern: %d,%d,%d,%d\n", tmp->busy_cadence.pattern[0], tmp->busy_cadence.pattern[1], (tmp->busy_cadence.length == 4) ? tmp->busy_cadence.pattern[2] : 0, (tmp->busy_cadence.length == 4) ? tmp->busy_cadence.pattern[3] : 0);
 			}
 			ast_cli(a->fd, "TDD: %s\n", tmp->tdd ? "yes" : "no");
 			ast_cli(a->fd, "Relax DTMF: %s\n", tmp->dtmfrelax ? "yes" : "no");
@@ -16664,6 +16658,40 @@ static unsigned long dahdi_display_text_option(const char *value)
 /*! process_dahdi() - No warnings on non-existing cofiguration keywords */
 #define PROC_DAHDI_OPT_NOWARN  (1 << 1)
 
+static void parse_busy_pattern(struct ast_variable *v, struct ast_dsp_busy_pattern *busy_cadence)
+{
+	int count_pattern = 0;
+	int norval = 0;
+	char *temp = NULL;
+
+	for (; ;) {
+		/* Scans the string for the next value in the pattern. If none, it checks to see if any have been entered so far. */
+		if(!sscanf(v->value, "%30d", &norval) && count_pattern == 0) { 			ast_log(LOG_ERROR, "busypattern= expects either busypattern=tonelength,quietlength or busypattern=t1length, q1length, t2length, q2length at line %d.\n", v->lineno);
+			break;
+		}
+
+		busy_cadence->pattern[count_pattern] = norval; 
+		
+		count_pattern++;
+		if (count_pattern == 4) {
+			break;
+		}
+
+		temp = strchr(v->value, ',');
+		if (temp == NULL) {
+			break;
+		}
+		v->value = temp + 1;
+	}
+	busy_cadence->length = count_pattern;
+
+	if (count_pattern % 2 != 0) { 
+		/* The pattern length must be divisible by two */
+		ast_log(LOG_ERROR, "busypattern= expects either busypattern=tonelength,quietlength or busypattern=t1length, q1length, t2length, q2length at line %d.\n", v->lineno);
+	}
+	
+}
+
 static int process_dahdi(struct dahdi_chan_conf *confp, const char *cat, struct ast_variable *v, int reload, int options)
 {
 	struct dahdi_pvt *tmp;
@@ -16789,9 +16817,7 @@ static int process_dahdi(struct dahdi_chan_conf *confp, const char *cat, struct
 		} else if (!strcasecmp(v->name, "busycount")) {
 			confp->chan.busycount = atoi(v->value);
 		} else if (!strcasecmp(v->name, "busypattern")) {
-			if (sscanf(v->value, "%30d,%30d", &confp->chan.busy_tonelength, &confp->chan.busy_quietlength) != 2) {
-				ast_log(LOG_ERROR, "busypattern= expects busypattern=tonelength,quietlength at line %d.\n", v->lineno);
-			}
+			parse_busy_pattern(v, &confp->chan.busy_cadence);
 		} else if (!strcasecmp(v->name, "callprogress")) {
 			confp->chan.callprogress &= ~CALLPROGRESS_PROGRESS;
 			if (ast_true(v->value))
diff --git a/include/asterisk/dsp.h b/include/asterisk/dsp.h
index bea0e6f5e..10ada9955 100644
--- a/include/asterisk/dsp.h
+++ b/include/asterisk/dsp.h
@@ -59,6 +59,13 @@
 
 struct ast_dsp;
 
+struct ast_dsp_busy_pattern {
+	/*! Number of elements. */
+	int length;
+	/*! Pattern elements in on/off time durations. */
+	int pattern[4];
+};
+
 enum threshold {
 	/* Array offsets */
 	THRESHOLD_SILENCE = 0,
@@ -76,7 +83,7 @@ void ast_dsp_set_threshold(struct ast_dsp *dsp, int threshold);
 void ast_dsp_set_busy_count(struct ast_dsp *dsp, int cadences);
 
 /*! \brief Set expected lengths of the busy tone */
-void ast_dsp_set_busy_pattern(struct ast_dsp *dsp, int tonelength, int quietlength);
+void ast_dsp_set_busy_pattern(struct ast_dsp *dsp, const struct ast_dsp_busy_pattern *cadence);
 
 /*! \brief Scans for progress indication in audio */
 int ast_dsp_call_progress(struct ast_dsp *dsp, struct ast_frame *inf);
diff --git a/main/dsp.c b/main/dsp.c
index 69989afe8..a83adc2a0 100644
--- a/main/dsp.c
+++ b/main/dsp.c
@@ -378,8 +378,7 @@ struct ast_dsp {
 	int ringtimeout;
 	int busymaybe;
 	int busycount;
-	int busy_tonelength;
-	int busy_quietlength;
+	struct ast_dsp_busy_pattern busy_cadence;
 	int historicnoise[DSP_HISTORY];
 	int historicsilence[DSP_HISTORY];
 	goertzel_state_t freqs[7];
@@ -1183,9 +1182,14 @@ int ast_dsp_busydetect(struct ast_dsp *dsp)
 	int avgsilence = 0, hitsilence = 0;
 #endif
 	int avgtone = 0, hittone = 0;
-	if (!dsp->busymaybe) {
-		return res;
+
+	/* if we have a 4 length pattern, the way busymaybe is set doesn't help us. */
+	if (dsp->busy_cadence.length != 4) {
+		if (!dsp->busymaybe) {
+			return res;
+		}
 	}
+
 	for (x = DSP_HISTORY - dsp->busycount; x < DSP_HISTORY; x++) {
 #ifndef BUSYDETECT_TONEONLY
 		avgsilence += dsp->historicsilence[x];
@@ -1239,23 +1243,60 @@ int ast_dsp_busydetect(struct ast_dsp *dsp)
 		res = 1;
 #endif
 	}
+
+	/* If we have a 4-length pattern, we can go ahead and just check it in a different way. */
+	if (dsp->busy_cadence.length == 4) {
+		int x;
+		int errors = 0;
+		int errors_max = ((4 * dsp->busycount) / 100.0) * BUSY_PAT_PERCENT;
+
+		for (x = DSP_HISTORY - (dsp->busycount); x < DSP_HISTORY; x += 2) {
+			int temp_error;
+			temp_error = abs(dsp->historicnoise[x] - dsp->busy_cadence.pattern[0]);
+			if ((temp_error * 100) / dsp->busy_cadence.pattern[0] > BUSY_PERCENT) {
+				errors++;
+			}
+
+			temp_error = abs(dsp->historicnoise[x + 1] - dsp->busy_cadence.pattern[2]);
+			if ((temp_error * 100) / dsp->busy_cadence.pattern[2] > BUSY_PERCENT) {
+				errors++;
+			}
+
+			temp_error = abs(dsp->historicsilence[x] - dsp->busy_cadence.pattern[1]);
+			if ((temp_error * 100) / dsp->busy_cadence.pattern[1] > BUSY_PERCENT) {
+				errors++;
+			}
+
+			temp_error = abs(dsp->historicsilence[x + 1] - dsp->busy_cadence.pattern[3]);
+			if ((temp_error * 100) / dsp->busy_cadence.pattern[3] > BUSY_PERCENT) {
+				errors++;
+			}
+		}
+
+		ast_debug(5, "errors = %d  max = %d\n", errors, errors_max);
+
+		if (errors <= errors_max) {
+			return 1;
+		}
+	}
+
 	/* If we know the expected busy tone length, check we are in the range */
-	if (res && (dsp->busy_tonelength > 0)) {
-		if (abs(avgtone - dsp->busy_tonelength) > (dsp->busy_tonelength*BUSY_PAT_PERCENT/100)) {
+	if (res && (dsp->busy_cadence.pattern[0] > 0)) {
+		if (abs(avgtone - dsp->busy_cadence.pattern[0]) > (dsp->busy_cadence.pattern[0]*BUSY_PAT_PERCENT/100)) {
 #ifdef BUSYDETECT_DEBUG
 			ast_debug(5, "busy detector: avgtone of %d not close enough to desired %d\n",
-				avgtone, dsp->busy_tonelength);
+				avgtone, dsp->busy_cadence.pattern[0]);
 #endif
 			res = 0;
 		}
 	}
 #ifndef BUSYDETECT_TONEONLY
 	/* If we know the expected busy tone silent-period length, check we are in the range */
-	if (res && (dsp->busy_quietlength > 0)) {
-		if (abs(avgsilence - dsp->busy_quietlength) > (dsp->busy_quietlength*BUSY_PAT_PERCENT/100)) {
+	if (res && (dsp->busy_cadence.pattern[1] > 0)) {
+		if (abs(avgsilence - dsp->busy_cadence.pattern[1]) > (dsp->busy_cadence.pattern[1] * BUSY_PAT_PERCENT / 100)) {
 #ifdef BUSYDETECT_DEBUG
 		ast_debug(5, "busy detector: avgsilence of %d not close enough to desired %d\n",
-			avgsilence, dsp->busy_quietlength);
+			avgsilence, dsp->busy_cadence.pattern[1]);
 #endif
 			res = 0;
 		}
@@ -1571,11 +1612,10 @@ void ast_dsp_set_busy_count(struct ast_dsp *dsp, int cadences)
 	dsp->busycount = cadences;
 }
 
-void ast_dsp_set_busy_pattern(struct ast_dsp *dsp, int tonelength, int quietlength)
+void ast_dsp_set_busy_pattern(struct ast_dsp *dsp, const struct ast_dsp_busy_pattern *cadence)
 {
-	dsp->busy_tonelength = tonelength;
-	dsp->busy_quietlength = quietlength;
-	ast_debug(1, "dsp busy pattern set to %d,%d\n", tonelength, quietlength);
+	dsp->busy_cadence = *cadence;
+	ast_debug(1, "dsp busy pattern set to %d,%d,%d,%d\n", cadence->pattern[0], cadence->pattern[1], (cadence->length == 4) ? cadence->pattern[2] : 0, (cadence->length == 4) ? cadence->pattern[3] : 0);
 }
 
 void ast_dsp_digitreset(struct ast_dsp *dsp)