diff -r e8a9785e63c3 -r 6f3a973fc29e include/ecrt.h
--- a/include/ecrt.h	Mon Sep 22 15:26:54 2008 +0000
+++ b/include/ecrt.h	Mon Sep 22 15:27:50 2008 +0000
@@ -923,9 +923,21 @@
  * VoE handler methods.
  ****************************************************************************/
 
+/** Sets the VoE header containing vendor ID and vendor type.
+ *
+ * A VoE message shall contain a 4-byte vendor ID, followed by a 2-byte vendor
+ * type at as header. These numbers can be set with this function.
+ */
+void ecrt_voe_handler_header(
+        ec_voe_handler_t *voe, /**< VoE handler. */
+        uint32_t vendor_id, /**< Vendor ID. */
+        uint16_t vendor_type /**< Vendor-specific type. */
+        );
+
 /** Access to the VoE handler's data.
  *
- * This function returns a pointer to the handler's internal memory.
+ * This function returns a pointer to the VoE handler's internal memory, after
+ * the VoE header (see ecrt_voe_handler_header()).
  *
  * - After a read operation was successful, the memory contains the received
  *   data. The size of the received data can be determined via
@@ -942,6 +954,9 @@
 
 /** Returns the current data size.
  *
+ * The data size is the size of the VoE data without the header (see
+ * ecrt_voe_handler_header()).
+ *
  * When the VoE handler is created, the data size is set to the size of the
  * reserved memory. At a write operation, the data size is set to the number
  * of bytes to write. After a read operation the size is set to the size of
@@ -960,7 +975,7 @@
  */
 void ecrt_voe_handler_write(
         ec_voe_handler_t *voe, /**< VoE handler. */
-        size_t size /**< Number of bytes to write. */
+        size_t size /**< Number of bytes to write (without the VoE header). */
         );
 
 /** Start a VoE read operation.