diff -ur /home/peter/src/mISDN.git/mISDN/drivers/isdn/hardware/mISDN/dsp.h ./dsp.h
--- /home/peter/src/mISDN.git/mISDN/drivers/isdn/hardware/mISDN/dsp.h	2008-01-03 21:45:40.000000000 +0100
+++ ./dsp.h	2008-01-12 21:44:00.000000000 +0100
@@ -115,7 +115,7 @@
 
 #define DSP_DTMF_NPOINTS 102
 
-#define ECHOCAN_BUFLEN 4*128
+#define ECHOCAN_BUFLEN 10*128
 
 typedef struct _dtmf_t {
 	int 		treshold; /* above this is dtmf (square of) */
diff -ur /home/peter/src/mISDN.git/mISDN/drivers/isdn/hardware/mISDN/dsp_cancel.h ./dsp_cancel.h
--- /home/peter/src/mISDN.git/mISDN/drivers/isdn/hardware/mISDN/dsp_cancel.h	2008-01-03 21:45:40.000000000 +0100
+++ ./dsp_cancel.h	2008-01-12 22:19:27.000000000 +0100
@@ -55,14 +55,13 @@
 	uint16_t echolastupdate;
 	char txbuf[ECHOCAN_BUFLEN];
 	int  txbuflen;
-	char rxbuf[ECHOCAN_BUFLEN];
-	int  rxbuflen;
 	int  underrun;
 	int  overflow;
+	int  delay;
 } ec_prv_t;
 
 static inline void *
-dsp_cancel_new(int deftaps, int training)
+dsp_cancel_new(int deftaps, int training, int delay)
 {
 	ec_prv_t *p;
 
@@ -78,10 +77,17 @@
 	p->echostate = training ? ECHO_STATE_PRETRAINING : ECHO_STATE_IDLE;
 	p->echolastupdate = 0;
 	p->txbuflen = 0;
-	p->rxbuflen = 0;
 	p->underrun = 0;
 	p->overflow = 0;
 
+	if (delay < 0) {
+		delay = 0;
+	} else if (delay > 512) {
+		delay = 512;
+	}
+
+	p->delay = delay;
+
 	return p;
 
 err2:
@@ -166,7 +172,7 @@
 	if (!p || !data)
 		return;
 
-	if (len <= p->txbuflen) {
+	if (len + p->delay <= p->txbuflen) {
 		char tmp[ECHOCAN_BUFLEN];
 		int delta = p->txbuflen - len;
 
@@ -177,7 +183,7 @@
 		memcpy(p->txbuf, tmp, delta);
 		p->txbuflen = delta;
 	} else {
-		if (p->underrun >= 4000) {
+		if (p->underrun >= 4000 + p->delay) {
 			printk("ECHOCAN: TXBUF Underrun:%d txbuflen:%d "
 			    "rxcancellen:%d\n", p->underrun, p->txbuflen, len);
 			p->underrun = 0;
diff -ur /home/peter/src/mISDN.git/mISDN/drivers/isdn/hardware/mISDN/dsp_kb1ec.c ./dsp_kb1ec.c
--- /home/peter/src/mISDN.git/mISDN/drivers/isdn/hardware/mISDN/dsp_kb1ec.c	2008-01-03 21:45:40.000000000 +0100
+++ ./dsp_kb1ec.c	2008-01-12 21:38:29.000000000 +0100
@@ -34,6 +34,7 @@
 {
 	int deftaps = 128,
 		training = 0,
+		delay = 0,
 		len;
 
 	if (!arg)
@@ -66,13 +67,16 @@
 			} else if (!strcmp(name, "training")) {
 				if (sscanf(val, "%d", &tmp) == 1)
 					training = tmp;
+			} else if (!strcmp(name, "delay")) {
+				if (sscanf(val, "%d", &tmp) == 1)
+					delay = tmp;
 			}
 		}
 	}
 
 _out:
-	printk(KERN_DEBUG "%s: creating %s with deftaps=%d and training=%d\n", __FUNCTION__, EC_TYPE, deftaps, training);
-	return dsp_cancel_new(deftaps, training);
+	printk(KERN_DEBUG "%s: creating %s with deftaps=%d, training=%d and delay=%d\n", __FUNCTION__, EC_TYPE, deftaps, training, delay);
+	return dsp_cancel_new(deftaps, training, delay);
 }
 
 static void free (void *p)
@@ -93,6 +97,7 @@
 static mISDN_dsp_element_arg_t args[] = {
 	{ "deftaps", "128", "Set the number of taps of cancellation." },
 	{ "training", "0", "Enable echotraining (0: disabled, 1: enabled)." },
+	{ "delay", "0", "Compensate for driver delay (number of taps)." },
 };
 
 static mISDN_dsp_element_t dsp_kb1ec = {
diff -ur /home/peter/src/mISDN.git/mISDN/drivers/isdn/hardware/mISDN/dsp_mec2.c ./dsp_mec2.c
--- /home/peter/src/mISDN.git/mISDN/drivers/isdn/hardware/mISDN/dsp_mec2.c	2008-01-03 21:45:40.000000000 +0100
+++ ./dsp_mec2.c	2008-01-12 21:39:13.000000000 +0100
@@ -35,6 +35,7 @@
 {
 	int deftaps = 128,
 		training = 0,
+		delay = 0,
 		len;
 
 	if (!arg)
@@ -67,13 +68,16 @@
 			} else if (!strcmp(name, "training")) {
 				if (sscanf(val, "%d", &tmp) == 1)
 					training = tmp;
+			} else if (!strcmp(name, "delay")) {
+				if (sscanf(val, "%d", &tmp) == 1)
+					delay = tmp;
 			}
 		}
 	}
 
 _out:
-	printk(KERN_DEBUG "%s: creating %s with deftaps=%d and training=%d\n", __FUNCTION__, EC_TYPE, deftaps, training);
-	return dsp_cancel_new(deftaps, training);
+	printk(KERN_DEBUG "%s: creating %s with deftaps=%d, training=%d and delay=%d\n", __FUNCTION__, EC_TYPE, deftaps, training, delay);
+	return dsp_cancel_new(deftaps, training, delay);
 }
 
 static void free (void *p)
@@ -94,6 +98,7 @@
 static mISDN_dsp_element_arg_t args[] = {
 	{ "deftaps", "128", "Set the number of taps of cancellation." },
 	{ "training", "0", "Enable echotraining (0: disabled, 1: enabled)." },
+	{ "delay", "0", "Compensate for driver delay (number of taps)." },
 };
 
 static mISDN_dsp_element_t dsp_mec2 = {
diff -ur /home/peter/src/mISDN.git/mISDN/drivers/isdn/hardware/mISDN/dsp_mg2ec.c ./dsp_mg2ec.c
--- /home/peter/src/mISDN.git/mISDN/drivers/isdn/hardware/mISDN/dsp_mg2ec.c	2008-01-03 21:45:40.000000000 +0100
+++ ./dsp_mg2ec.c	2008-01-12 22:22:46.000000000 +0100
@@ -34,6 +34,7 @@
 {
 	int deftaps = 128,
 		training = 0,
+		delay = 0,
 		len;
 
 	if (!arg)
@@ -66,13 +67,16 @@
 			} else if (!strcmp(name, "training")) {
 				if (sscanf(val, "%d", &tmp) == 1)
 					training = tmp;
+			} else if (!strcmp(name, "delay")) {
+				if (sscanf(val, "%d", &tmp) == 1)
+					delay = tmp;
 			}
 		}
 	}
 
 _out:
-	printk(KERN_DEBUG "%s: creating %s with deftaps=%d and training=%d\n", __FUNCTION__, EC_TYPE, deftaps, training);
-	return dsp_cancel_new(deftaps, training);
+	printk(KERN_DEBUG "%s: creating %s with deftaps=%d, training=%d and delay=%d\n", __FUNCTION__, EC_TYPE, deftaps, training, delay);
+	return dsp_cancel_new(deftaps, training, delay);
 }
 
 static void free (void *p)
@@ -93,6 +97,7 @@
 static mISDN_dsp_element_arg_t args[] = {
 	{ "deftaps", "128", "Set the number of taps of cancellation." },
 	{ "training", "0", "Enable echotraining (0: disabled, 1: enabled)." },
+	{ "delay", "0", "Compensate for driver delay (number of taps)." },
 };
 
 static mISDN_dsp_element_t dsp_mg2ec = {
diff -ur /home/peter/src/mISDN.git/mISDN/drivers/isdn/hardware/mISDN/dsp_octwareec.c ./dsp_octwareec.c
--- /home/peter/src/mISDN.git/mISDN/drivers/isdn/hardware/mISDN/dsp_octwareec.c	2008-01-03 21:45:40.000000000 +0100
+++ ./dsp_octwareec.c	2008-01-12 22:23:38.000000000 +0100
@@ -35,6 +35,7 @@
 {
 	int deftaps = 128,
 		training = 0,
+		delay = 0,
 		len;
 
 	if (!arg)
@@ -67,13 +68,16 @@
 			} else if (!strcmp(name, "training")) {
 				if (sscanf(val, "%d", &tmp) == 1)
 					training = tmp;
+			} else if (!strcmp(name, "delay")) {
+				if (sscanf(val, "%d", &tmp) == 1)
+					delay = tmp;
 			}
 		}
 	}
 
 _out:
-	printk(KERN_DEBUG "%s: creating %s with deftaps=%d and training=%d\n", __FUNCTION__, EC_TYPE, deftaps, training);
-	return dsp_cancel_new(deftaps, training);
+	printk(KERN_DEBUG "%s: creating %s with deftaps=%d, training=%d and delay=%d\n", __FUNCTION__, EC_TYPE, deftaps, training, delay);
+	return dsp_cancel_new(deftaps, training, delay);
 }
 
 static void free (void *p)
@@ -94,6 +98,7 @@
 static mISDN_dsp_element_arg_t args[] = {
 	{ "deftaps", "128", "Set the number of taps of cancellation." },
 	{ "training", "0", "Enable echotraining (0: disabled, 1: enabled)." },
+	{ "delay", "0", "Compensate for driver delay (number of taps)." },
 };
 
 static mISDN_dsp_element_t dsp_octwareec = {
diff -ur /home/peter/src/mISDN.git/mISDN/drivers/isdn/hardware/mISDN/dsp_oslec.c ./dsp_oslec.c
--- /home/peter/src/mISDN.git/mISDN/drivers/isdn/hardware/mISDN/dsp_oslec.c	2008-01-03 21:45:40.000000000 +0100
+++ ./dsp_oslec.c	2008-01-12 21:49:05.000000000 +0100
@@ -41,7 +41,7 @@
 static void* new (const char *arg)
 {
 	int deftaps = 128,
-		training = 0,
+	        delay = 0,
 		len;
 
 	if (!arg)
@@ -71,16 +71,16 @@
 			if (!strcmp(name, "deftaps")) {
 				if (sscanf(val, "%d", &tmp) == 1)
 					deftaps = tmp;
-			} else if (!strcmp(name, "training")) {
+			} else if (!strcmp(name, "delay")) {
 				if (sscanf(val, "%d", &tmp) == 1)
-					training = tmp;
+					delay = tmp;
 			}
 		}
 	}
 
 _out:
-	printk(KERN_DEBUG "%s: creating %s with deftaps=%d and training=%d\n", __FUNCTION__, EC_TYPE, deftaps, training);
-	return dsp_cancel_new(deftaps, training);
+	printk(KERN_DEBUG "%s: creating %s with deftaps=%d and delay=%d\n", __FUNCTION__, EC_TYPE, deftaps, delay);
+	return dsp_cancel_new(deftaps, 0, delay);
 }
 
 static void free (void *p)
@@ -100,7 +100,7 @@
 
 static mISDN_dsp_element_arg_t args[] = {
 	{ "deftaps", "128", "Set the number of taps of cancellation." },
-	{ "training", "0", "Enable echotraining (0: disabled, 1: enabled)." },
+	{ "delay", "0", "Compensate for driver delay (number of taps)." },
 };
 
 static mISDN_dsp_element_t dsp_oslec = {