diff --git a/isup/generator/create_structs.st b/isup/generator/create_structs.st
index 0ec91b4..0178d0c 100644
--- a/isup/generator/create_structs.st
+++ b/isup/generator/create_structs.st
@@ -188,6 +188,9 @@ Object subclass: StructCreator [
 ' % {aDef className}.
         ].
 
+        aDef className = 'ISUPMessageType'
+                ifTrue: [^self].
+
         type :=
 'MSGFixedField subclass: %1 [
     <category: ''OsmoNetwork-ISUP''>
diff --git a/isup/isup_generated.st b/isup/isup_generated.st
index 9e43b25..219b19b 100644
--- a/isup/isup_generated.st
+++ b/isup/isup_generated.st
@@ -421,16 +421,6 @@ MSGVariableField subclass: ISUPForwardGVNS [
     ISUPForwardGVNS class >> spec [ <category: 'field'> ^ '3.66' ]
 ]
 
-MSGFixedField subclass: ISUPMessageType [
-    <category: 'OsmoNetwork-ISUP'>
-    <comment: 'I am an auto generated ISUP fixed field.'>
-
-    ISUPMessageType class >> parameterName [ <category: 'field'> ^ 'Message type' ]
-    ISUPMessageType class >> parameterValue [ <category: 'field'> ^ ISUPConstants parMessageType ]
-    ISUPMessageType class >> octalLength [ <category: 'field'> ^ 1 ]
-    ISUPMessageType class >> spec [ <category: 'field'> ^ '2.1' ]
-]
-
 MSGVariableField subclass: ISUPTransitNetworkSelection [
     <category: 'OsmoNetwork-ISUP'>
     <comment: 'I am an auto generated ISUP variable.'>