diff --git a/src/ca/baseNMIU.cpp b/src/ca/baseNMIU.cpp
index 0c6ad4248..b55bab15e 100644
--- a/src/ca/baseNMIU.cpp
+++ b/src/ca/baseNMIU.cpp
@@ -25,14 +25,5 @@ baseNMIU::~baseNMIU ()
 {
 }
 
-class netSubscription * baseNMIU::isSubscription ()
-{
-    return 0;
-}
 
-void baseNMIU::show ( unsigned /* level */ ) const
-{
-    ::printf ( "CA IO primitive at %p\n", 
-        static_cast <const void *> ( this ) );
-}
 
diff --git a/src/ca/netIO.h b/src/ca/netIO.h
index 4be60afcd..f195f4fae 100644
--- a/src/ca/netIO.h
+++ b/src/ca/netIO.h
@@ -42,8 +42,8 @@ public:
         arrayElementCount count ) = 0;
     virtual void completion ( unsigned type, 
         arrayElementCount count, const void *pData ) = 0;
-    virtual class netSubscription * isSubscription ();
-    virtual void show ( unsigned level ) const;
+    virtual class netSubscription * isSubscription () = 0;
+    virtual void show ( unsigned level ) const = 0;
     ca_uint32_t getID () const;
     nciu & channel () const;
 protected:
@@ -79,7 +79,7 @@ public:
         arrayElementCount count );
 private:
     const arrayElementCount count;
-    cacStateNotify &notify;
+    cacStateNotify & notify;
     const unsigned type;
     const unsigned mask;
     netSubscription ( nciu &chan, unsigned type, arrayElementCount count, 
@@ -123,6 +123,7 @@ private:
         tsFreeList < class netReadNotifyIO, 1024, epicsMutexNOOP > & );
 #   endif
     ~netReadNotifyIO ();
+    class netSubscription * isSubscription ();
     netReadNotifyIO ( const netReadNotifyIO & );
     netReadNotifyIO & operator = ( const netReadNotifyIO & );
 };
@@ -151,6 +152,7 @@ private:
     void operator delete ( void *,
         tsFreeList < class netWriteNotifyIO, 1024, epicsMutexNOOP > & );
 #   endif
+    class netSubscription * isSubscription ();
     netWriteNotifyIO ( const netWriteNotifyIO & );
     netWriteNotifyIO & operator = ( const netWriteNotifyIO & );
     ~netWriteNotifyIO ();
diff --git a/src/ca/netReadNotifyIO.cpp b/src/ca/netReadNotifyIO.cpp
index db0b1045e..d24cf2e44 100644
--- a/src/ca/netReadNotifyIO.cpp
+++ b/src/ca/netReadNotifyIO.cpp
@@ -31,9 +31,6 @@ void netReadNotifyIO::show ( unsigned level ) const
 {
     ::printf ( "read notify IO at %p\n", 
         static_cast < const void * > ( this ) );
-    if ( level > 0u ) {
-        this->baseNMIU::show ( level - 1u );
-    }
 }
 
 void netReadNotifyIO::destroy ( cacRecycle & recycle )
@@ -64,3 +61,9 @@ void netReadNotifyIO::completion ( unsigned type,
     this->notify.completion ( type, count, pData );
 }
 
+class netSubscription * netReadNotifyIO::isSubscription ()
+{
+    return 0;
+}
+
+
diff --git a/src/ca/netSubscription.cpp b/src/ca/netSubscription.cpp
index 989e6a3eb..f2470d940 100644
--- a/src/ca/netSubscription.cpp
+++ b/src/ca/netSubscription.cpp
@@ -55,9 +55,6 @@ void netSubscription::show ( unsigned level ) const
         static_cast < const void * > ( this ), 
         dbf_type_to_text ( static_cast < int > ( this->type ) ), 
         this->count, this->mask );
-    if ( level > 0u ) {
-        this->baseNMIU::show ( level - 1u );
-    }
 }
 
 void netSubscription::completion ()
diff --git a/src/ca/netWriteNotifyIO.cpp b/src/ca/netWriteNotifyIO.cpp
index 6eeca0f07..c2f51fe7f 100644
--- a/src/ca/netWriteNotifyIO.cpp
+++ b/src/ca/netWriteNotifyIO.cpp
@@ -31,9 +31,6 @@ void netWriteNotifyIO::show ( unsigned level ) const
 {
     ::printf ( "read write notify IO at %p\n", 
         static_cast < const void * > ( this ) );
-    if ( level > 0u ) {
-        this->baseNMIU::show ( level - 1u );
-    }
 }
 
 void netWriteNotifyIO::destroy ( cacRecycle & recycle )
@@ -65,3 +62,8 @@ void netWriteNotifyIO::completion ( unsigned /* type */,
     this->chan.getClient().printf ( "Write response with data ?\n" );
 }
 
+class netSubscription * netWriteNotifyIO::isSubscription ()
+{
+    return 0;
+}
+