diff --git a/python/devsup/_nullapi.py b/python/devsup/_nullapi.py
index 7699ad9..49ef52e 100644
--- a/python/devsup/_nullapi.py
+++ b/python/devsup/_nullapi.py
@@ -17,6 +17,9 @@ class Record(object):
     def name(self):
         """Record name
         """
+    def isPyRecord(self):
+        """Is this record using Python Device.
+        """
     def info(self, key):
         """info(key)
         info(key, default)
@@ -30,7 +33,7 @@ class Record(object):
         for this record
         """
 
-    def scan(self, sync=False):
+    def scan(self, sync=False, reason=None, force=0):
         """scan(sync=False)
         
         Scan this record.  If sync is False then a
@@ -38,10 +41,17 @@ class Record(object):
         is scannined immidately on the current thread.
         """
 
+    def asyncStart(self):
+        pass
+    def asyncFinish(self, reason=None):
+        pass
+
 def Field(object):
     """Handle for field operations
     
     f = Field("rec:name.HOPR")
+    
+    Field objects implement the buffer protocol.
     """
     def __init__(self, fld):
         pass
@@ -67,3 +77,7 @@ def Field(object):
         
         Must be an Int, Float or str
         """
+
+    def getarray(self):
+        """Return a numpy ndarray refering to this field for in-place operations.
+        """
diff --git a/python/devsup/interfaces.py b/python/devsup/interfaces.py
new file mode 100644
index 0000000..5be1b0a
--- /dev/null
+++ b/python/devsup/interfaces.py
@@ -0,0 +1,18 @@
+
+from zope.interface import Interface
+
+class DeviceSupport(Interface):
+    def detach(record):
+        """Disconnect from the record.
+
+        This is the last method called.
+        """
+
+    def allowScan(record):
+        """Return True to allow SCAN='I/O Intr'
+        or False to prevent this.
+        """
+
+    def process(record, reason):
+        """Callback for record processing action.
+        """