diff --git a/core/dev/radio.h b/core/dev/radio.h
index 4bd828266..5b9144286 100644
--- a/core/dev/radio.h
+++ b/core/dev/radio.h
@@ -42,7 +42,7 @@
  *
  * This file is part of the Contiki operating system.
  *
- * $Id: radio.h,v 1.1 2006/06/17 22:41:17 adamdunkels Exp $
+ * $Id: radio.h,v 1.2 2007/05/15 07:51:57 adamdunkels Exp $
  */
 
 /**
@@ -55,6 +55,26 @@
 #ifndef __RADIO_H__
 #define __RADIO_H__
 
+/**
+ * The structure of a device driver for a radio in Contiki.
+ */
+struct radio_driver {
+  /** Send a packet  */
+  int (* send)(const u8_t *buf, u16_t len);
+
+  /** Read a received packet. */
+  u16_t (* read)(u8_t *buf, u16_t bufsize);
+
+  /** Set a function to be called when a packet has been received. */
+  void (* set_receive_function)(void (*f)(const struct radio_driver *d));
+
+  /** Turn the radio on. */
+  int (* on)(void);
+
+  /** Turn the radio off. */
+  int (* off)(void);
+};
+
 
 /**
  * \brief      Turn radio on.