diff --git a/IPython/kernel/zmq/displayhook.py b/IPython/kernel/zmq/displayhook.py
index ecedbe7..ef1c643 100644
--- a/IPython/kernel/zmq/displayhook.py
+++ b/IPython/kernel/zmq/displayhook.py
@@ -10,7 +10,7 @@ from session import extract_header, Session
 class ZMQDisplayHook(object):
     """A simple displayhook that publishes the object's repr over a ZeroMQ
     socket."""
-    topic=None
+    topic=b'pyout'
 
     def __init__(self, session, pub_socket):
         self.session = session
diff --git a/IPython/kernel/zmq/iostream.py b/IPython/kernel/zmq/iostream.py
index c549a58..8d66b8f 100644
--- a/IPython/kernel/zmq/iostream.py
+++ b/IPython/kernel/zmq/iostream.py
@@ -44,6 +44,7 @@ class OutStream(object):
         self.session = session
         self.pub_socket = pub_socket
         self.name = name
+        self.topic = b'stream.' + py3compat.cast_bytes(name)
         self.parent_header = {}
         self._new_buffer()
         self._buffer_lock = threading.Lock()
diff --git a/IPython/kernel/zmq/zmqshell.py b/IPython/kernel/zmq/zmqshell.py
index 422c0c8..00a13e0 100644
--- a/IPython/kernel/zmq/zmqshell.py
+++ b/IPython/kernel/zmq/zmqshell.py
@@ -61,7 +61,7 @@ class ZMQDisplayPublisher(DisplayPublisher):
     session = Instance(Session)
     pub_socket = Instance(SocketABC)
     parent_header = Dict({})
-    topic = CBytes(b'displaypub')
+    topic = CBytes(b'display_data')
 
     def set_parent(self, parent):
         """Set the parent for outbound messages."""