diff --git a/src/main/java/org/onosproject/olt/AccessDeviceService.java b/src/main/java/org/onosproject/olt/AccessDeviceService.java
index bd82f48..868f877 100644
--- a/src/main/java/org/onosproject/olt/AccessDeviceService.java
+++ b/src/main/java/org/onosproject/olt/AccessDeviceService.java
@@ -17,12 +17,16 @@
 package org.onosproject.olt;
 
 import org.onlab.packet.VlanId;
+import org.onosproject.event.ListenerService;
 import org.onosproject.net.ConnectPoint;
+import org.onosproject.olt.api.AccessDeviceEvent;
+import org.onosproject.olt.api.AccessDeviceListener;
 
 /**
  * Service for interacting with an access device (OLT).
  */
-public interface AccessDeviceService {
+public interface AccessDeviceService
+        extends ListenerService<AccessDeviceEvent, AccessDeviceListener> {
 
     /**
      * Provisions connectivity for a subscriber on an access device.
@@ -38,4 +42,5 @@
      * @param port subscriber's connection point
      */
     void removeSubscriber(ConnectPoint port);
+
 }