--- dahdi-linux-complete-2.2.0-rc4+2.2.0-rc2/linux/include/dahdi/kernel.h	2009-04-30 01:24:04.000000000 +0700
+++ dahdi-linux-complete/linux/include/dahdi/kernel.h	2009-05-29 19:37:08.760144988 +0700
@@ -249,6 +249,12 @@
 	 * \return Nothing.
 	 */
 	void (*echocan_NLP_toggle)(struct dahdi_echocan_state *ec, unsigned int enable);
+
+	/*! \brief Process an array of TX audio samples through the HPF.
+	 *
+	 * \return Nothing.
+	 */
+	void (*echocan_hpf_tx)(struct dahdi_echocan_state *ec, short *tx, u32 size);
 };
 
 /*! A factory for creating instances of software echo cancelers to be used on DAHDI channels. */