diff --git a/pyad2usb/ad2usb.py b/pyad2usb/ad2usb.py
index acdcd24..0d334d7 100644
--- a/pyad2usb/ad2usb.py
+++ b/pyad2usb/ad2usb.py
@@ -191,6 +191,7 @@ class AD2USB(object):
     on_zone_restore = event.Event('Called when the device detects that a fault is restored.')
     on_low_battery = event.Event('Called when the device detects a low battery.')
     on_panic = event.Event('Called when the device detects a panic.')
+    on_relay_changed = event.Event('Called when a relay is opened or closed on an expander board.')
 
     # Mid-level Events
     on_message = event.Event('Called when a message has been received from the device.')
@@ -235,6 +236,7 @@ class AD2USB(object):
         self._fire_status = (False, 0)
         self._battery_status = (False, 0)
         self._panic_status = None
+        self._relay_status = dict()
 
         self.address = 18
         self.configbits = 0xFF00
@@ -387,13 +389,18 @@ class AD2USB(object):
 
             if header == '!EXP' or header == '!REL':
                 msg = messages.ExpanderMessage(data)
+
                 self._update_internal_states(msg)
+
             elif header == '!RFX':
                 msg = self._handle_rfx(data)
+
             elif header == '!LRR':
                 msg = self._handle_lrr(data)
+
             elif data.startswith('!Ready'):
                 self.on_boot()
+
             elif data.startswith('!CONFIG'):
                 self._handle_config(data)
 
@@ -510,6 +517,12 @@ class AD2USB(object):
                     self._fire_status = (message.fire_alarm, time.time())
                     self.on_fire(self._fire_status)
 
+        elif isinstance(message, messages.ExpanderMessage):
+            if message.type == messages.ExpanderMessage.RELAY:
+                self._relay_status[(message.address, message.channel)] = message.value
+
+                self.on_relay_changed(message)
+
         self._update_zone_tracker(message)
 
     def _update_zone_tracker(self, message):
diff --git a/pyad2usb/messages.py b/pyad2usb/messages.py
index 5ea834e..c8c6dd7 100644
--- a/pyad2usb/messages.py
+++ b/pyad2usb/messages.py
@@ -138,9 +138,9 @@ class ExpanderMessage(object):
         address, channel, value = values.split(',')
 
         self.raw = data
-        self.address = address
-        self.channel = channel
-        self.value = value
+        self.address = int(address)
+        self.channel = int(channel)
+        self.value = int(value)
 
         if header == '!EXP':
             self.type = ExpanderMessage.ZONE
@@ -173,7 +173,7 @@ class RFMessage(object):
         """
         String conversion operator.
         """
-        return 'rf > {0}: {1}'.format(self.serial_number, self.value)
+        return 'rf > {0}: {1:x}'.format(self.serial_number, self.value)
 
     def _parse_message(self, data):
         """
diff --git a/pyad2usb/zonetracking.py b/pyad2usb/zonetracking.py
index 6ab3303..ce0a1e4 100644
--- a/pyad2usb/zonetracking.py
+++ b/pyad2usb/zonetracking.py
@@ -82,13 +82,14 @@ class Zonetracker(object):
                 zone = self._expander_to_zone(int(message.address), int(message.channel))
 
                 status = Zone.CLEAR
-                if int(message.value) == 1:
+                if message.value == 1:
                     status = Zone.FAULT
-                elif int(message.value) == 2:
+                elif message.value == 2:
                     status = Zone.CHECK
 
                 try:
                     self._update_zone(zone, status=status)
+
                 except IndexError:
                     self._add_zone(zone, status=status)
 
@@ -114,7 +115,6 @@ class Zonetracker(object):
                 # of whether or not the 3-digit mode is enabled... so we have to pull it out of the
                 # alpha message.
                 if zone == 191:
-                    # TODO: parse message text.
                     zone_regex = re.compile('^CHECK (\d+).*$')
 
                     m = zone_regex.match(message.text)
@@ -127,6 +127,7 @@ class Zonetracker(object):
                 if zone in self._zones_faulted:
                     self._update_zone(zone)
                     self._clear_zones(zone)
+
                 else:
                     status = Zone.FAULT
                     if message.check_zone:
diff --git a/test.py b/test.py
index eaf1488..43df484 100755
--- a/test.py
+++ b/test.py
@@ -106,6 +106,9 @@ def handle_panic(sender, args):
 def handle_rfx(sender, args):
     print 'RFX', args
 
+def handle_relay(sender, args):
+    print 'RELAY', args
+
 def upload_usb():
     dev = pyad2usb.ad2usb.devices.USBDevice()
 
@@ -254,6 +257,7 @@ def test_socket():
     a2u.on_zone_fault += handle_fault
     a2u.on_zone_restore += handle_restore
     a2u.on_rfx_message += handle_rfx
+    a2u.on_relay_changed += handle_relay
     #
     #a2u.on_fire += handle_fire
     #a2u.on_low_battery += handle_battery