--- a/rvinterf/etmsync/interf.c	Mon Feb 24 03:42:47 2014 +0000
+++ b/rvinterf/etmsync/interf.c	Mon Feb 24 04:41:57 2014 +0000
@@ -121,3 +121,36 @@
 	}
 	return(0);
 }
+
+etm_pkt_exch(outbuf, outlen)
+	u_char *outbuf;
+{
+	int i, c;
+
+	outbuf[0] = RVT_TM_HEADER;
+	c = 0;
+	for (i = 1; i <= outlen; i++)
+		c ^= outbuf[i];
+	outbuf[i] = c;
+	target_pkt_exch(outbuf, outlen + 2);
+	if (rvi_msg[1] != RVT_TM_HEADER) {
+		printf("error: packet from target is not ETM!\n");
+		return(ERROR_TARGET);
+	}
+	if (rvi_msg_len < 5) {
+		printf("error: ETM response packet is too short\n");
+		return(ERROR_TARGET);
+	}
+	c = 0;
+	for (i = 2; i < rvi_msg_len; i++)
+		c ^= rvi_msg[i];
+	if (c) {
+		printf("ETM response checksum error!\n");
+		return(ERROR_TARGET);
+	}
+	if (rvi_msg[2] != outbuf[1]) {
+		printf("error: target response is from wrong ETM component\n");
+		return(ERROR_TARGET);
+	}
+	return(0);
+}