diff --git a/TODO b/TODO
index 52c1217..8ce4dc4 100644
--- a/TODO
+++ b/TODO
@@ -32,6 +32,8 @@ General:
   need to re-send the 401/403?
 * Compare with MGCPCommands and share code... in SIPRequest
 * Via we should indicate the received address and port...
+* Verify that status code is valid. It used to be done inside the
+  grammar but that is not the right place.
 
 
 * 3xx, 4xx, 5xx, 6xx are final. We should not allow any other messages.
diff --git a/grammar/SIPGrammar.st b/grammar/SIPGrammar.st
index fe5d40d..ed1a5a6 100644
--- a/grammar/SIPGrammar.st
+++ b/grammar/SIPGrammar.st
@@ -23,7 +23,8 @@ PP.PPCompositeParser subclass: SIPGrammar [
       message_body SIPVersion StatusCode ReasonPhrase 
       extension_header header_name header_value 
       Request RequestLine Method extension_method
-      RequestURI quoted_string token
+      RequestURI quoted_string token commonUriParser paramchar
+      header
     |
     "http://sofia-sip.org/repos/sofia-sip/libsofia-sip-ua/sip/GRAMMAR"
     <category: 'OsmoSIP-Grammar'>
@@ -69,14 +70,17 @@ PP.PPCompositeParser subclass: SIPGrammar [
 
     SIPURI [
         <category: 'request'>
-        ^ 'sip:' asParser , self userinfo optional,
-          self hostport, self uri_parameters, self headers optional. 
+        ^ 'sip:' asParser , commonUriParser
+    ]
+
+    commonUriParser [
+        ^self userinfo optional, self hostport, self uri_parameters,
+        self headers optional.
     ]
 
     SIPSURI [
         <category: 'request'>
-        ^ 'sips:' asParser , self userinfo optional,
-          self hostport, self uri_parameters, self headers optional. 
+        ^ 'sips:' asParser , commonUriParser
     ]
 
     hostport [
@@ -113,17 +117,17 @@ PP.PPCompositeParser subclass: SIPGrammar [
 
     pname [
         <category: 'generic'>
-        ^ self paramchar plus flatten
+        ^paramchar
     ]
 
     pvalue [
         <category: 'generic'>
-        ^ self paramchar plus flatten
+        ^paramchar
     ]
 
     paramchar [
         <category: 'generic'>
-        ^ self param_unreserved / self unreserved / self escaped
+        ^ (self param_unreserved / self unreserved / self escaped) plus flatten
     ]
 
     param_unreserved [
@@ -134,12 +138,12 @@ PP.PPCompositeParser subclass: SIPGrammar [
 
     headers [
         <category: 'generic'>
-        ^ $? asParser, self header, ($& asParser, self header) star
+        ^ $? asParser, header, ($& asParser, header) star
     ]
 
     header [
         <category: 'generic'>
-        ^ self hname, $= asParser, self hvalue
+        ^self hname, $= asParser, self hvalue
     ]
 
     hname [
@@ -247,61 +251,7 @@ PP.PPCompositeParser subclass: SIPGrammar [
     StatusCode [
         <category: 'response'>
         "Combined into one..."
-        ^ '100' asParser / "Trying"
-          '101' asParser / "Early Dialog.. of Linphone"
-          '180' asParser / "Ringing"
-          '181' asParser / "Call Is Being Forwarded"
-          '182' asParser / "Queued"
-          '183' asParser / "Session Progress"
-
-          '200' asParser / "OK"
-
-          '300' asParser / "Multiple Choices"
-          '301' asParser / "Moved Permanently"
-          '302' asParser / "Moved Temporarily"
-          '380' asParser / "Alternative Service"
-
-          '400' asParser / "Bad Request"
-          '401' asParser / "Unauthorized"
-          '402' asParser / "Payment Required"
-          '403' asParser / "Forbidden"
-          '404' asParser / "Not Found"
-          '405' asParser / "Method Not Allowed"
-          '406' asParser / "Not Acceptable"
-          '407' asParser / "Proxy Authentication Required"
-          '408' asParser / "Request Timeout"
-          '410' asParser / "Gone"
-          '413' asParser / "Request Entity Too Large"
-          '414' asParser / "Request-URI Too Large"
-          '415' asParser / "Unsupported Media Type"
-          '416' asParser / "Unsupported URI Scheme"
-          '420' asParser / "Bad Extension"
-          '421' asParser / "Extension Required"
-          '423' asParser / "Interval Too Brief"
-          '480' asParser / "Temporarily not available"
-          '481' asParser / "Call Leg/Transaction Does Not Exist"
-          '482' asParser / "Loop Detected"
-          '483' asParser / "Too Many Hops"
-          '484' asParser / "Address Incomplete"
-          '485' asParser / "Ambiguous"
-          '486' asParser / "Busy Here"
-          '487' asParser / "Request Terminated"
-          '488' asParser / "Not Acceptable Here"
-          '491' asParser / "Request Pending"
-          '493' asParser / "Undecipherable"
-
-          '500' asParser / "Internal Server Error"
-          '501' asParser / "Not Implemented"
-          '502' asParser / "Bad Gateway"
-          '503' asParser / "Service Unavailable"
-          '504' asParser / "Server Time-out"
-          '505' asParser / "SIP Version not supported"
-          '513' asParser / "Message Too Large"
-
-          '600' asParser / "Busy Everywhere"
-          '603' asParser /"Decline"
-          '604' asParser /"Does not exist anywhere"
-          '606' asParser "Not Acceptable"
+        ^ (#digit asParser min: 3 max: 3) flatten
     ]
 
     ReasonPhrase [