diff --git a/apps/radio-test/radio-test.c b/apps/radio-test/radio-test.c
new file mode 100644
index 000000000..187db258c
--- /dev/null
+++ b/apps/radio-test/radio-test.c
@@ -0,0 +1,155 @@
+/*
+ * Copyright (c) 2006, Swedish Institute of Computer Science.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the Institute nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * $Id: radio-test.c,v 1.1 2006/10/05 09:23:54 adamdunkels Exp $
+ *
+ * -----------------------------------------------------------------
+ *
+ * Author  : Adam Dunkels, Joakim Eriksson, Niclas Finne
+ * Created : 2006-03-07
+ * Updated : $Date: 2006/10/05 09:23:54 $
+ *           $Revision: 1.1 $
+ *
+ * Simple application to indicate connectivity between two nodes:
+ *
+ * - Red led indicates a packet sent via radio (one packet sent each second)
+ * - Yellow led indicates that this node can hear the other node but not
+ *   necessary vice versa (unidirectional communication).
+ * - Green led indicates that both nodes can communicate with each
+ *   other (bidirectional communication)
+ */
+
+#include "contiki-esb.h"
+#include <string.h>
+
+PROCESS(radio_test_process, "Radio test");
+AUTOSTART_PROCESSES(&radio_test_process);
+
+#define ON  1
+#define OFF 0
+
+#define HEADER "RTST"
+#define PACKET_SIZE 20
+#define PORT 2345
+
+struct indicator {
+  int onoff;
+  int led;
+  clock_time_t interval;
+  struct etimer timer;
+};
+
+/*---------------------------------------------------------------------*/
+static void
+set(struct indicator *indicator, int onoff) {
+  if(indicator->onoff ^ onoff) {
+    indicator->onoff = onoff;
+    if(onoff) {
+      leds_on(indicator->led);
+    } else {
+      leds_off(indicator->led);
+    }
+  }
+  if(onoff) {
+    etimer_set(&indicator->timer, indicator->interval);
+  }
+}
+/*---------------------------------------------------------------------*/
+PROCESS_THREAD(radio_test_process, ev, data)
+{
+  static struct etimer send_timer;
+  static struct uip_udp_conn *conn;
+  static struct indicator recv, other, flash;
+
+  PROCESS_BEGIN();
+
+  /* Initialize the indicators */
+  recv.onoff = other.onoff = flash.onoff = OFF;
+  recv.interval = other.interval = CLOCK_SECOND;
+  flash.interval = 1;
+  recv.led = LEDS_YELLOW;
+  other.led = LEDS_GREEN;
+  flash.led = LEDS_RED;
+
+  conn = udp_broadcast_new(HTONS(PORT), NULL);
+  etimer_set(&send_timer, CLOCK_SECOND);
+
+  while(1) {
+    PROCESS_WAIT_EVENT();
+
+    if(ev == PROCESS_EVENT_TIMER) {
+      if(data == &send_timer) {
+	etimer_reset(&send_timer);
+	tcpip_poll_udp(conn);
+
+      } else if(data == &other.timer) {
+	set(&other, OFF);
+
+      } else if(data == &recv.timer) {
+	set(&recv, OFF);
+
+      } else if(data == &flash.timer) {
+	set(&flash, OFF);
+      }
+
+    } else if(ev == tcpip_event) {
+
+      if(uip_poll()) {
+	/* send packet */
+	memcpy(uip_sappdata, HEADER, sizeof(HEADER));
+	((char *)uip_sappdata)[sizeof(HEADER)] = recv.onoff;
+	/* send arbitrary data to fill the packet size */
+	uip_send(uip_sappdata, PACKET_SIZE);
+
+	set(&flash, ON);
+      }
+
+      if(uip_newdata()) {
+	/* packet received */
+	if(uip_datalen() < PACKET_SIZE
+	   || strncmp((char *)uip_appdata, HEADER, sizeof(HEADER))) {
+	  /* invalid message */
+	  leds_blink();
+
+	} else {
+	  set(&recv, ON);
+	  set(&other, ((char *)uip_appdata)[sizeof(HEADER)] ? ON : OFF);
+
+	  /* synchronize the sending to keep the nodes from sending
+	     simultaneously */
+	  etimer_set(&send_timer, CLOCK_SECOND);
+	  etimer_adjust(&send_timer, - (int) (CLOCK_SECOND >> 1));
+
+	  beep();
+	}
+      }
+    }
+  }
+  PROCESS_END();
+}
+/*---------------------------------------------------------------------*/