diff --git a/src/xp/services/protocol/conbus_event_protocol.py b/src/xp/services/protocol/conbus_event_protocol.py
index 60d1859..630fc4c 100644
--- a/src/xp/services/protocol/conbus_event_protocol.py
+++ b/src/xp/services/protocol/conbus_event_protocol.py
@@ -378,7 +378,7 @@ def call_later(
         """
         return self._reactor.callLater(delay, callable_action, *args, **kw)
 
-    def buildProtocol(self, addr: IAddress) -> protocol.Protocol:
+    def buildProtocol(self, addr: Optional[IAddress]) -> protocol.Protocol:
         """
         Build protocol instance for connection.