diff --git a/core/net/mac/nullmac.c b/core/net/mac/nullmac.c
index f10e403fe..14163dbba 100644
--- a/core/net/mac/nullmac.c
+++ b/core/net/mac/nullmac.c
@@ -28,7 +28,7 @@
  *
  * This file is part of the Contiki operating system.
  *
- * $Id: nullmac.c,v 1.2 2007/05/19 13:19:22 oliverschmidt Exp $
+ * $Id: nullmac.c,v 1.3 2007/05/25 08:07:15 adamdunkels Exp $
  */
 
 /**
@@ -39,32 +39,63 @@
  */
 
 #include "net/mac/nullmac.h"
+#include "net/rime/rimebuf.h"
 
 static const struct radio_driver *radio;
-
+static void (* receiver_callback)(const struct mac_driver *);
 /*---------------------------------------------------------------------------*/
-static void
+static int
 send(void)
 {
-  radio->send(rimebuf_hdrptr(), rimebuf_totlen());
+  return radio->send(rimebuf_hdrptr(), rimebuf_totlen());
 }
 /*---------------------------------------------------------------------------*/
 static void
 input(const struct radio_driver *d)
+{
+  receiver_callback(&nullmac_driver);
+}
+/*---------------------------------------------------------------------------*/
+static int
+read(void)
 {
   int len;
   rimebuf_clear();
   len = radio->read(rimebuf_dataptr(), RIMEBUF_SIZE);
   rimebuf_set_datalen(len);
-  rime_input();
+  return len;
+}
+/*---------------------------------------------------------------------------*/
+static void
+set_receive_function(void (* recv)(const struct mac_driver *))
+{
+  receiver_callback = recv;
+}
+/*---------------------------------------------------------------------------*/
+static int
+on(void)
+{
+  return radio->on();
+}
+/*---------------------------------------------------------------------------*/
+static int
+off(void)
+{
+  return radio->off();
 }
 /*---------------------------------------------------------------------------*/
 void
 nullmac_init(const struct radio_driver *d)
 {
-  rime_set_output(send);
   radio = d;
   radio->set_receive_function(input);
   radio->on();
 }
 /*---------------------------------------------------------------------------*/
+const struct mac_driver nullmac_driver = {
+  send,
+  read,
+  set_receive_function,
+  on,
+  off,
+};
diff --git a/core/net/mac/nullmac.h b/core/net/mac/nullmac.h
index a00582f55..72b78de59 100644
--- a/core/net/mac/nullmac.h
+++ b/core/net/mac/nullmac.h
@@ -28,7 +28,7 @@
  *
  * This file is part of the Contiki operating system.
  *
- * $Id: nullmac.h,v 1.1 2007/05/15 07:40:22 adamdunkels Exp $
+ * $Id: nullmac.h,v 1.2 2007/05/25 08:07:15 adamdunkels Exp $
  */
 
 /**
@@ -41,10 +41,11 @@
 #ifndef __NULLMAC_H__
 #define __NULLMAC_H__
 
-#include "contiki-net.h"
-
+#include "net/mac/mac.h"
 #include "dev/radio.h"
 
-void nullmac_init(const struct radio_driver *d);
+extern const struct mac_driver nullmac_driver;
+
+void nullmac_init(const struct radio_driver *r);
 
 #endif /* __NULLMAC_H__ */
diff --git a/core/net/mac/xmac.c b/core/net/mac/xmac.c
index 32d6697a2..4476e0369 100644
--- a/core/net/mac/xmac.c
+++ b/core/net/mac/xmac.c
@@ -30,7 +30,7 @@
  *
  * This file is part of the Contiki operating system.
  *
- * $Id: xmac.c,v 1.5 2007/05/22 22:10:30 oliverschmidt Exp $
+ * $Id: xmac.c,v 1.6 2007/05/25 08:07:15 adamdunkels Exp $
  */
 
 /**
@@ -47,18 +47,22 @@
 #include "net/rime.h"
 #include "dev/radio.h"
 
+#include "contiki-conf.h"
+
 #ifdef CHAMELEON
 #include "net/chameleon/packattr.h"
 #endif
 
+#define WITH_RECEIVER 1
+#define WITH_QUEUE 0
+
+/*
 #undef XMAC_CONF_ON_TIME
 #undef XMAC_CONF_OFF_TIME
 
-#define WITH_RECEIVER 1
-#define WITH_QUEUE 1
 #define XMAC_CONF_ON_TIME RTIMER_ARCH_SECOND / 100
 #define XMAC_CONF_OFF_TIME RTIMER_ARCH_SECOND / 10
-
+*/
 
 #if WITH_RECEIVER
 extern
@@ -94,7 +98,7 @@ static struct pt pt;
 #define OFF_TIME (ON_TIME * 10)
 #endif
 
-#define STROBE_WAIT_TIME ON_TIME / 2
+#define STROBE_WAIT_TIME (ON_TIME) / 2
 
 static volatile unsigned char should_be_awake = 0;
 static volatile unsigned char someone_is_sending = 0;
@@ -124,10 +128,19 @@ static const struct radio_driver *radio;
 #define PRINTF(...)
 #endif
 
+static void (* receiver_callback)(const struct mac_driver *);
+/*---------------------------------------------------------------------------*/
+static void
+set_receive_function(void (* recv)(const struct mac_driver *))
+{
+  receiver_callback = recv;
+}
 /*---------------------------------------------------------------------------*/
 static char
 powercycle(struct rtimer *t, void *ptr)
 {
+  int r;
+  
   PT_BEGIN(&pt);
 
   while(1) {
@@ -144,9 +157,10 @@ powercycle(struct rtimer *t, void *ptr)
 	should_be_awake = 0;
       }
     }
-    if(rtimer_set(t, RTIMER_TIME(t) + OFF_TIME, 1,
-		  (void (*)(struct rtimer *, void *))powercycle, ptr)) {
-      PRINTF("xmac: could not set rtimer\n");
+    r = rtimer_set(t, RTIMER_TIME(t) + OFF_TIME, 1,
+		   (void (*)(struct rtimer *, void *))powercycle, ptr);
+    if(r) {
+      PRINTF("xmac: 1 could not set rtimer %d\n", r);
     }
 /*     t2 = rtimer_arch_now(); */
 /*     printf("xmac 1 %d\n", t2 - t1); */
@@ -163,9 +177,10 @@ powercycle(struct rtimer *t, void *ptr)
       radio_is_on = 1;
       LEDS_ON(LEDS_RED);
     }
-    if(rtimer_set(t, RTIMER_TIME(t) + ON_TIME, 1,
-		  (void (*)(struct rtimer *, void *))powercycle, ptr)) {
-      PRINTF("xmac: could not set rtimer\n");
+    r = rtimer_set(t, RTIMER_TIME(t) + ON_TIME, 1,
+		   (void (*)(struct rtimer *, void *))powercycle, ptr);
+    if(r) {
+      PRINTF("xmac: 2 could not set rtimer %d\n", r);
     }
 /*     t2 = rtimer_arch_now(); */
 /*     printf("xmac 2 %d\n", t2 - t1); */
@@ -197,7 +212,7 @@ powercycle(struct rtimer *t, void *ptr)
   PT_END(&pt);
 }
 /*---------------------------------------------------------------------------*/
-static void
+static int
 send(void)
 {
   rtimer_clock_t t0, t1;
@@ -211,8 +226,10 @@ send(void)
   radio_is_on = 1;
   
   /*  printf("xmac_send\n");*/
+#if !CHAMELEON
   PRINTF("xmac: send() len %d to %d.%d\n", rimebuf_totlen(),
 	 uc_receiver.u8[0], uc_receiver.u8[1]);
+#endif
     
   rimebuf_hdralloc(sizeof(struct xmac_hdr));
   hdr = rimebuf_hdrptr();
@@ -252,6 +269,8 @@ send(void)
     radio->send((const u8_t *)&msg, sizeof(struct xmac_hdr));
 
     while(RTIMER_CLOCK_LT(RTIMER_NOW(), t + STROBE_WAIT_TIME)) {
+      printf("now %d then %d wait %d\n",
+	     RTIMER_NOW(), t, STROBE_WAIT_TIME);
       /* See if we got an ACK */
       /*      printf("befor read\n");*/
       len = radio->read((u8_t *)&msg, sizeof(struct xmac_hdr));
@@ -293,11 +312,12 @@ send(void)
     PRINTF("xmac: could not set rtimer after send\n");
   }
   we_are_sending = 0;
+  return 1;
 
 }
 /*---------------------------------------------------------------------------*/
 static struct queuebuf *queued_packet;
-static void
+static int
 qsend(void)
 {
   if(someone_is_sending) {
@@ -305,22 +325,33 @@ qsend(void)
 	   should_be_awake, someone_is_sending, we_are_sending, radio_is_on);
     if(queued_packet != NULL) {
       RIMESTATS_ADD(contentiondrop);
+      return 0;
     } else {
 #if WITH_QUEUE
       queued_packet = queuebuf_new_from_rimebuf();
+      return 1;
 #else
       RIMESTATS_ADD(contentiondrop);
+      return 0;
 #endif
     }
   } else {
     PRINTF("xmac: send immediately.\n");
-    send();
+    return send();
   }
     
 }
 /*---------------------------------------------------------------------------*/
 static void
 input(const struct radio_driver *d)
+{
+  if(receiver_callback) {
+    receiver_callback(&xmac_driver);
+  }
+}
+/*---------------------------------------------------------------------------*/
+static int
+read(void)
 {
   struct xmac_hdr *hdr;
   u8_t len;
@@ -328,7 +359,7 @@ input(const struct radio_driver *d)
   rimebuf_clear();
 
   PRINTF("xmac: input ");
-  len = d->read(rimebuf_dataptr(), RIMEBUF_SIZE);
+  len = radio->read(rimebuf_dataptr(), RIMEBUF_SIZE);
   PRINTF("%d bytes\n", len);
   
   if(len > 0) {
@@ -382,16 +413,17 @@ input(const struct radio_driver *d)
       someone_is_sending = 0;
       should_be_awake = 0;
       PRINTF("xmac: final packet received\n");
-      rime_input();
-      /* XXX send queued packet. */
+
+      /* XXX should set timer to send queued packet later. */
       if(queued_packet != NULL) {
-	queuebuf_to_rimebuf(queued_packet);
 	queuebuf_free(queued_packet);
 	queued_packet = NULL;
-	send();
       }
+
+      return rimebuf_totlen();
     }
   }
+  return 0;
 }
 /*---------------------------------------------------------------------------*/
 void
@@ -403,8 +435,27 @@ xmac_init(const struct radio_driver *d)
   rtimer_set(&rt, RTIMER_NOW() + OFF_TIME, 1,
 	     (void (*)(struct rtimer *, void *))powercycle, NULL);
 
-  rime_set_output(qsend);
   radio = d;
   radio->set_receive_function(input);
 }
 /*---------------------------------------------------------------------------*/
+static int
+on(void)
+{
+  return radio->on();
+}
+/*---------------------------------------------------------------------------*/
+static int
+off(void)
+{
+  return radio->off();
+}
+/*---------------------------------------------------------------------------*/
+const struct mac_driver xmac_driver =
+  {
+    qsend,
+    read,
+    set_receive_function,
+    on,
+    off
+  };
diff --git a/core/net/mac/xmac.h b/core/net/mac/xmac.h
index 3f6339987..a3b3197f5 100644
--- a/core/net/mac/xmac.h
+++ b/core/net/mac/xmac.h
@@ -28,7 +28,7 @@
  *
  * This file is part of the Contiki operating system.
  *
- * $Id: xmac.h,v 1.3 2007/05/22 20:55:24 adamdunkels Exp $
+ * $Id: xmac.h,v 1.4 2007/05/25 08:07:15 adamdunkels Exp $
  */
 
 /**
@@ -41,10 +41,11 @@
 #ifndef __XMAC_H__
 #define __XMAC_H__
 
-#include "contiki-net.h"
-
+#include "net/mac/mac.h"
 #include "dev/radio.h"
 
+extern const struct mac_driver xmac_driver;
+
 void xmac_init(const struct radio_driver *d);
 
 #endif /* __XMAC_H__ */
diff --git a/core/net/rime.h b/core/net/rime.h
index 6d2bcb152..8149aac1b 100644
--- a/core/net/rime.h
+++ b/core/net/rime.h
@@ -33,7 +33,7 @@
  *
  * This file is part of the Contiki operating system.
  *
- * $Id: rime.h,v 1.8 2007/05/22 20:53:24 adamdunkels Exp $
+ * $Id: rime.h,v 1.9 2007/05/25 08:06:44 adamdunkels Exp $
  */
 
 /**
@@ -54,13 +54,14 @@
 #include "net/rime/ruc.h"
 #include "net/rime/sibc.h"
 
+#include "net/mac/mac.h"
 /**
  * \brief      Initialize Rime
  *
  *             This function should be called from the system boot up
  *             code to initialize Rime.
  */
-void rime_init(void);
+void rime_init(const struct mac_driver *);
 
 /**
  * \brief      Send an incoming packet to Rime
diff --git a/core/net/rime/rime.c b/core/net/rime/rime.c
index 983b36206..16ca53353 100644
--- a/core/net/rime/rime.c
+++ b/core/net/rime/rime.c
@@ -33,7 +33,7 @@
  *
  * This file is part of the Contiki operating system.
  *
- * $Id: rime.c,v 1.9 2007/05/22 20:56:10 adamdunkels Exp $
+ * $Id: rime.c,v 1.10 2007/05/25 08:06:44 adamdunkels Exp $
  */
 
 /**
@@ -44,32 +44,31 @@
  */
 
 #include "net/rime.h"
+#include "net/mac/mac.h"
 
-static void (* output)(void);
-
+static const struct mac_driver *mac;
+/*---------------------------------------------------------------------------*/
+static void
+input(const struct mac_driver *r)
+{
+  int len;
+  len = mac->read();
+  if(len > 0) {
+    RIMESTATS_ADD(rx);
+    abc_input_packet();
+  }
+}
 /*---------------------------------------------------------------------------*/
 void
-rime_init(void)
+rime_init(const struct mac_driver *m)
 {
   ctimer_init();
   queuebuf_init();
   route_init();
   rimebuf_clear();
-  output = NULL;
   neighbor_init();
-}
-/*---------------------------------------------------------------------------*/
-void
-rime_input(void)
-{
-  RIMESTATS_ADD(rx);
-  abc_input_packet();
-}
-/*---------------------------------------------------------------------------*/
-void
-rime_set_output(void (*f)(void))
-{
-  output = f;
+  mac = m;
+  mac->set_receive_function(input);
 }
 /*---------------------------------------------------------------------------*/
 void
@@ -77,8 +76,8 @@ rime_output(void)
 {
   RIMESTATS_ADD(tx);
   rimebuf_compact();
-  if(output) {
-    output();
+  if(mac) {
+    mac->send();
   }
 }
 /*---------------------------------------------------------------------------*/