diff --git a/bacnet-stack/include/bacdef.h b/bacnet-stack/include/bacdef.h
index 246eda0f..4456fb44 100644
--- a/bacnet-stack/include/bacdef.h
+++ b/bacnet-stack/include/bacdef.h
@@ -37,7 +37,26 @@
 
 /* This stack implements this version of BACnet */
 #define BACNET_PROTOCOL_VERSION 1
-#define BACNET_PROTOCOL_REVISION 10
+/* Although this stack can implement a later revision,
+ * sometimes another revision is required */
+#ifndef BACNET_PROTOCOL_REVISION
+#define BACNET_PROTOCOL_REVISION 12
+#endif
+
+/* there are a few dependencies on the BACnet Protocol-Revision */
+#if (BACNET_PROTOCOL_REVISION == 9)
+    /* from 135-2008 version of the BACnet Standard */
+    #define MAX_ASHRAE_OBJECT_TYPE 38
+    #define MAX_BACNET_SERVICES_SUPPORTED 40
+#elif (BACNET_PROTOCOL_REVISION == 12)
+    /* from 135-2010 version of the BACnet Standard */
+    #define MAX_ASHRAE_OBJECT_TYPE 51
+    #define MAX_BACNET_SERVICES_SUPPORTED 40
+#else
+    #define MAX_ASHRAE_OBJECT_TYPE 51
+    #define MAX_BACNET_SERVICES_SUPPORTED 40
+#endif
+
 
 /* largest BACnet Instance Number */
 /* Also used as a device instance number wildcard address */
diff --git a/bacnet-stack/include/bacenum.h b/bacnet-stack/include/bacenum.h
index 84c8aedd..95b88ac8 100644
--- a/bacnet-stack/include/bacenum.h
+++ b/bacnet-stack/include/bacenum.h
@@ -936,8 +936,6 @@ typedef enum {
     OBJECT_POSITIVE_INTEGER_VALUE = 48,
     OBJECT_TIME_PATTERN_VALUE = 49,
     OBJECT_TIME_VALUE = 50,
-
-    MAX_ASHRAE_OBJECT_TYPE = 51,
     /* used for bit string loop */
     PROPRIETARY_BACNET_OBJECT_TYPE = 128,
     MAX_BACNET_OBJECT_TYPE = 1024
@@ -1122,11 +1120,10 @@ typedef enum {
     SERVICE_SUPPORTED_TIME_SYNCHRONIZATION = 32,
     SERVICE_SUPPORTED_UTC_TIME_SYNCHRONIZATION = 36,
     SERVICE_SUPPORTED_WHO_HAS = 33,
-    SERVICE_SUPPORTED_WHO_IS = 34,
+    SERVICE_SUPPORTED_WHO_IS = 34
     /* Other services to be added as they are defined. */
     /* All values in this production are reserved */
     /* for definition by ASHRAE. */
-    MAX_BACNET_SERVICES_SUPPORTED = 40
 } BACNET_SERVICES_SUPPORTED;
 
 typedef enum {