diff --git a/pyiec61850/iec61850.i b/pyiec61850/iec61850.i
index 65e0906f..d4a91afb 100644
--- a/pyiec61850/iec61850.i
+++ b/pyiec61850/iec61850.i
@@ -41,6 +41,11 @@ DataAttribute* toDataAttribute(ModelNode * MN)
 %include "iec61850_dynamic_model.h"
 %include "iec61850_cdc.h"
 %include "linked_list.h"
+
+/* User-defined data types, also used: */
+typedef uint64_t msSinceEpoch;
+typedef uint64_t nsSinceEpoch;
+
 ModelNode* toModelNode(LogicalNode *);
 ModelNode* toModelNode(DataObject *);
 DataAttribute* toDataAttribute(DataObject *);