diff --git a/library/NS_Types.ttcn b/library/NS_Types.ttcn
index 6432d6c..63ed24d 100644
--- a/library/NS_Types.ttcn
+++ b/library/NS_Types.ttcn
@@ -56,7 +56,7 @@
 		NS_CAUSE_BVCI_UNKNOWN_AT_NSE			('00000101'B),
 		NS_CAUSE_SEMANTICALLY_INCORRECT_PDU		('00001000'B),
 		NS_CAUSE_PDU_NOT_COMPATIBLE_WITH_PROTOCOL_STATE	('00001010'B),
-		NS_CAUSE_PROTOCOL_ERROR_UNSPEIFIED		('00001011'B),
+		NS_CAUSE_PROTOCOL_ERROR_UNSPECIFIED		('00001011'B),
 		NS_CAUSE_INVALID_ESSENTIAL_IE			('00001100'B),
 		NS_CAUSE_MISSING_ESSENTIAL_IE			('00001101'B),
 		NS_CAUSE_INVALID_NR_OF_IPv4_ENDPOINTS		('00001110'B),