Index: dahdi-base.c
===================================================================
--- dahdi-base.c	(revision 4971)
+++ dahdi-base.c	(working copy)
@@ -7390,6 +7414,8 @@
 
 static inline void __dahdi_real_transmit(struct dahdi_chan *chan)
 {
+	short txlins[DAHDI_CHUNKSIZE];
+        int x;
 	/* Called with chan->lock held */
 #ifdef	OPTIMIZE_CHANMUTE
 	if(likely(chan->chanmute))
@@ -7401,6 +7427,19 @@
 	} else {
 		__dahdi_transmit_chunk(chan, chan->writechunk);
 	}
+
+	if (!chan->ec_current) return;
+	if (!chan->ec_current->echo_can_array_hpf_tx) return;
+
+	/* hook to allow HPF filtering of audio leaving tx (D/A) port, this
+           inproves performance when using soft phones */
+	for (x = 0; x < DAHDI_CHUNKSIZE; x++)
+		txlins[x] = DAHDI_XLAW(chan->writechunk[x], chan);
+
+	chan->ec_current->echo_can_array_hpf_tx(chan->ec_state, txlins);
+
+	for (x = 0; x < DAHDI_CHUNKSIZE; x++)
+		chan->writechunk[x] = DAHDI_LIN2X((int) txlins[x], chan);
 }
 
 static void __dahdi_getempty(struct dahdi_chan *ms, unsigned char *buf)