--- a/master/globals.h	Thu Nov 06 08:54:14 2014 +0100
+++ b/master/globals.h	Thu Nov 06 08:55:35 2014 +0100
@@ -142,6 +142,9 @@
 } ec_slave_state_t;
 
 /** Supported mailbox protocols.
+ *
+ * Not to mix up with the mailbox type field in the mailbox header defined in
+ * master/mailbox.h.
  */
 enum {
     EC_MBOX_AOE = 0x01, /**< ADS over EtherCAT */

--- a/master/mailbox.h	Thu Nov 06 08:54:14 2014 +0100
+++ b/master/mailbox.h	Thu Nov 06 08:55:35 2014 +0100
@@ -46,8 +46,10 @@
 #define EC_MBOX_HEADER_SIZE 6
 
 /** Mailbox types.
+ *
+ * These are used in the 'Type' field of the mailbox header.
  */
-enum ec_mbox_types {
+enum {
     EC_MBOX_TYPE_EOE = 0x02,
     EC_MBOX_TYPE_COE = 0x03,
     EC_MBOX_TYPE_FOE = 0x04,