diff --git a/bacnet-stack/datalink.c b/bacnet-stack/datalink.c
new file mode 100644
index 00000000..8ffd6534
--- /dev/null
+++ b/bacnet-stack/datalink.c
@@ -0,0 +1,50 @@
+/*####COPYRIGHTBEGIN####
+ -------------------------------------------
+ Copyright (C) 2007 Steve Karg
+
+ This program is free software; you can redistribute it and/or
+ modify it under the terms of the GNU General Public License
+ as published by the Free Software Foundation; either version 2
+ of the License, or (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program; if not, write to:
+ The Free Software Foundation, Inc.
+ 59 Temple Place - Suite 330
+ Boston, MA  02111-1307, USA.
+
+ As a special exception, if other files instantiate templates or
+ use macros or inline functions from this file, or you compile
+ this file and link it with other works to produce a work based
+ on this file, this file does not by itself cause the resulting
+ work to be covered by the GNU General Public License. However
+ the source code for this file must still be made available in
+ accordance with section (3) of the GNU General Public License.
+
+ This exception does not invalidate any other reasons why a work
+ based on this file might be covered by the GNU General Public
+ License.
+ -------------------------------------------
+####COPYRIGHTEND####*/
+#include "datalink.h"
+
+/* Function pointers - point to your datalink */
+bool (*datalink_init)(char *ifname);
+
+int (*datalink_send_pdu)(BACNET_ADDRESS * dest,
+    BACNET_NPDU_DATA * npdu_data, uint8_t * pdu, unsigned pdu_len);
+
+uint16_t (*datalink_receive)(BACNET_ADDRESS * src,
+    uint8_t * pdu, uint16_t max_pdu, unsigned timeout);
+
+void (*datalink_cleanup)(void);
+
+void (*datalink_get_broadcast_address)(BACNET_ADDRESS * dest);
+
+void (*datalink_get_my_address)(BACNET_ADDRESS * my_address);
+