--- a/master/slave.h	Tue Oct 17 07:30:01 2006 +0000
+++ b/master/slave.h	Tue Oct 17 14:10:29 2006 +0000
@@ -67,8 +67,8 @@
     /**< SAVEOP (mailbox communication and input update) */
     EC_SLAVE_STATE_OP = 0x08,
     /**< OP (mailbox communication and input/output update) */
-    EC_ACK = 0x10
-    /**< Acknoledge bit (no state) */
+    EC_SLAVE_STATE_ACK_ERR = 0x10
+    /**< Acknoledge/Error bit (no actual state) */
 }
 ec_slave_state_t;