diff --git kb1ec.h kb1ec.h
index e0f63f6..c2d46fc 100644
--- kb1ec.h
+++ kb1ec.h
@@ -41,6 +41,8 @@
 #define FREE(a) free(a)
 #endif
 
+#define ABS(a) abs(a!=-32768?a:-32767)
+
 /* Uncomment to provide summary statistics for overall echo can performance every 4000 samples */ 
 /* #define MEC2_STATS 4000 */
 
@@ -138,6 +140,8 @@ struct echo_can_state {
 	int avg_Lu_i_toolow; 
 	int avg_Lu_i_ok;
 #endif 
+	short lastsig[256];
+	int lastpos;
 
 };
 
@@ -294,12 +298,49 @@ static inline short echo_can_update(struct echo_can_state *ec, short iref, short
   			ec->N_d);
 	rs >>= 15;
 
-	/* eq. (3): compute the output value (see figure 3) and the error
-	 * note: the error is the same as the output signal when near-end
-	 * speech is not present
-	 */
-	u = isig - rs;
-  
+	ec->lastsig[ec->lastpos++] = isig;
+	if (ec->lastpos >= 256)
+		ec->lastpos = 0;
+
+	for (k=0; k < 256; k++) {
+		if (isig != ec->lastsig[k])
+			break;
+	}
+
+	if (isig == 0) {
+		u = 0;
+	} else if (k == 256) {
+		u = isig;
+	} else {
+		if (rs < -32768) {
+			rs = -32768;
+			ec->HCNTR_d = DEFAULT_HANGT;
+			memset(ec->a_i, 0, sizeof(int) * ec->N_d);
+			memset(ec->a_s, 0, sizeof(short) * ec->N_d);
+		} else if (rs > 32767) {
+			rs = 32767;
+			ec->HCNTR_d = DEFAULT_HANGT;
+			memset(ec->a_i, 0, sizeof(int) * ec->N_d);
+			memset(ec->a_s, 0, sizeof(short) * ec->N_d);
+		}
+
+		if (ABS(ABS(rs)-ABS(isig)) > 3000)
+		{
+			rs = 0;
+			memset(ec->a_i, 0, sizeof(int) * ec->N_d);
+			memset(ec->a_s, 0, sizeof(short) * ec->N_d);
+		}
+
+		/* eq. (3): compute the output value (see figure 3) and the error
+		 * note: the error is the same as the output signal when near-end
+		 * speech is not present
+		 */
+		u = isig - rs;
+
+		if (u / isig < 0)
+			u = isig - (rs >> 1);
+	}
+
 	/* Push a copy of the output value sample into its circular buffer */
 	add_cc_s(&ec->u_s, u);
 
diff --git zaptel-base.c zaptel-base.c
index 9777ba6..fd0652c 100644
--- zaptel-base.c
+++ zaptel-base.c
@@ -371,6 +371,8 @@ struct zt_zone {
 
 static struct zt_span *spans[ZT_MAX_SPANS];
 static struct zt_chan *chans[ZT_MAX_CHANNELS]; 
+static struct zt_ec_data ec_data_preload[ZT_MAX_CHANNELS]; 
+static struct zt_ec_data ec_data_dump[ZT_MAX_CHANNELS]; 
 
 static int maxspans = 0;
 static int maxchans = 0;
@@ -3217,6 +3219,25 @@ static int zt_common_ioctl(struct inode *node, struct file *file, unsigned int c
 #endif
 #endif /* ALLOW_CHAN_DIAG */
 		break;
+	case ZT_EC_PRELOAD:
+		if (copy_from_user(&j, (void *)data, sizeof(int)))
+			return -EFAULT;
+		if (copy_from_user(&ec_data_preload[j], (void *)data, sizeof(struct zt_ec_data)))
+			return -EFAULT;
+		return 0;
+	case ZT_EC_DUMP:
+		if (copy_from_user(&j, (void *)data, sizeof(int)))
+			return -EFAULT;
+		chan = chans[j];
+		if (chan && chan->ec && chan->ec->a_i && chan->ec->a_s) {
+			memset(&ec_data_dump[j], 0, sizeof(struct zt_ec_data));
+			ec_data_dump[j].N_d = chan->ec->N_d;
+			memcpy(ec_data_dump[j].a_i, chan->ec->a_i, chan->ec->N_d * sizeof(int));
+			memcpy(ec_data_dump[j].a_s, chan->ec->a_s, chan->ec->N_d * sizeof(short));
+		}
+		if (copy_to_user((void *)data, &ec_data_dump[j], sizeof(struct zt_ec_data)))
+				return -EFAULT;
+		return 0;
 	default:
 		return -ENOTTY;
 	}
@@ -4402,6 +4423,16 @@ static int zt_chan_ioctl(struct inode *inode, struct file *file, unsigned int cm
 				ec = echo_can_create(j, 0);
 				if (!ec)
 					return -ENOMEM;
+				if (ec_data_preload[chan->channo].N_d == ec->N_d)
+				{
+					printk("Using preloaded ec data for channel %d\n", chan->channo);
+					memcpy(ec->a_i, ec_data_preload[chan->channo].a_i, ec->N_d*sizeof(int));
+					memcpy(ec->a_s, ec_data_preload[chan->channo].a_s, ec->N_d*sizeof(short));
+				}
+				else
+				{
+					printk("No preloaded ec data for channel %d\n", chan->channo);
+				}
 				spin_lock_irqsave(&chan->lock, flags);
 				chan->echocancel = j;
 				chan->ec = ec;