diff --git a/src/bacnet/bacenum.h b/src/bacnet/bacenum.h
index 56c72ade..7181c2ab 100644
--- a/src/bacnet/bacenum.h
+++ b/src/bacnet/bacenum.h
@@ -585,6 +585,7 @@ typedef enum {
 } BACNET_DEVICE_STATUS;
 
 typedef enum {
+    /* Enumerated values 0-255 are reserved for definition by ASHRAE. */
     /* Acceleration */
     UNITS_METERS_PER_SECOND_PER_SECOND = 166,
     /* Area */
@@ -863,7 +864,13 @@ typedef enum {
     UNITS_MOLE_PERCENT = 252,
     UNITS_PASCAL_SECONDS = 253,
     UNITS_MILLION_STANDARD_CUBIC_FEET_PER_MINUTE = 254,
-    /* 255 - NOT USED */
+    UNITS_RESERVED_RANGE_MAX = 255,
+    /* Enumerated values 256-47807 may be used by others
+       subject to the procedures and constraints described in Clause 23. */
+    UNITS_PROPRIETARY_RANGE_MIN = 256,
+    UNITS_PROPRIETARY_RANGE_MAX = 47807,
+    /* Enumerated values 47808-49999 are reserved for definition by ASHRAE. */
+    UNITS_RESERVED_RANGE_MIN2 = 47808,
     UNITS_STANDARD_CUBIC_FEET_PER_DAY = 47808,
     UNITS_MILLION_STANDARD_CUBIC_FEET_PER_DAY = 47809,
     UNITS_THOUSAND_CUBIC_FEET_PER_DAY = 47810,
@@ -872,15 +879,14 @@ typedef enum {
     /* 47813 - NOT USED */
     UNITS_MILLIREMS = 47814,
     UNITS_MILLIREMS_PER_HOUR = 47815,
-    /* Enumerated values 0-255 and 47808-49999 are reserved for
-       definition by ASHRAE. */
-    /* Enumerated values 256-47807 and 50000-65535 may be used by others
+    UNITS_RESERVED_RANGE_MAX2 = 49999,
+    UNITS_PROPRIETARY_RANGE_MIN2 = 50000,
+    /* Enumerated values 50000-65535 may be used by others
        subject to the procedures and constraints described in Clause 23. */
     /* do the proprietary range inside of enum so that
        compilers will allocate adequate sized datatype for enum
        which is used to store decoding */
-    UNITS_PROPRIETARY_RANGE_MIN = 256,
-    UNITS_PROPRIETARY_RANGE_MAX = 65535
+    UNITS_PROPRIETARY_RANGE_MAX2 = 65535
 } BACNET_ENGINEERING_UNITS;
 
 typedef enum {
diff --git a/src/bacnet/bactext.c b/src/bacnet/bactext.c
index 27c2ba66..f060da81 100644
--- a/src/bacnet/bactext.c
+++ b/src/bacnet/bactext.c
@@ -933,8 +933,19 @@ INDTEXT_DATA bacnet_engineering_unit_names[] = {
 
 const char *bactext_engineering_unit_name(unsigned index)
 {
-    return indtext_by_index_split_default(bacnet_engineering_unit_names, index,
-        256, ASHRAE_Reserved_String, Vendor_Proprietary_String);
+    if (index <= UNITS_RESERVED_RANGE_MAX) {
+        return indtext_by_index_default(bacnet_engineering_unit_names,
+            index, ASHRAE_Reserved_String);
+    } else if (index <= UNITS_PROPRIETARY_RANGE_MAX) {
+        return Vendor_Proprietary_String;
+    } else if (index <= UNITS_RESERVED_RANGE_MAX2) {
+        return indtext_by_index_default(bacnet_engineering_unit_names,
+            index, ASHRAE_Reserved_String);
+    } else if (index <= UNITS_PROPRIETARY_RANGE_MAX2) {
+        return Vendor_Proprietary_String;
+    }
+
+    return ASHRAE_Reserved_String;
 }
 
 bool bactext_engineering_unit_index(