diff --git a/secop/poller.py b/secop/poller.py
index 4102b76..0a61f42 100644
--- a/secop/poller.py
+++ b/secop/poller.py
@@ -113,7 +113,8 @@ class Poller(PollerBase):
     def __init__(self, name):
         '''create a poller'''
         self.queues = {polltype: [] for polltype in self.DEFAULT_FACTORS}
-        self._stopped = Event()
+        self._event = Event()
+        self._stopped = False
         self.maxwait = 3600
         self.name = name
 
@@ -142,6 +143,11 @@ class Poller(PollerBase):
             if not hasattr(module, 'pollinterval'):
                 raise ProgrammingError("module %s must have a pollinterval"
                                        % module.name)
+            if pname == 'is_connected':
+                if hasattr(module, 'registerReconnectCallback'):
+                    module.registerReconnectCallback(self.name, self.trigger_all)
+                else:
+                    module.log.warning("%r has 'is_connected' but no 'registerReconnectCallback'" % module)
             if polltype == AUTO: # covers also pobj.poll == True
                 if pname in ('value', 'status'):
                     polltype = DYNAMIC
@@ -184,7 +190,10 @@ class Poller(PollerBase):
             else:
                 interval = module.pollinterval * factor
                 mininterval = interval
-            due = max(lastdue + interval, pobj.timestamp + interval * 0.5)
+            if due == 0:
+                due = now # do not look at timestamp after trigger_all
+            else:
+                due = max(lastdue + interval, pobj.timestamp + interval * 0.5)
             if now >= due:
                 module.pollOneParam(pname)
                 done = True
@@ -194,6 +203,13 @@ class Poller(PollerBase):
             heapreplace(queue, (due, lastdue, pollitem))
         return 0
 
+    def trigger_all(self):
+        for _, queue in sorted(self.queues.items()):
+            for idx, (_, lastdue, pollitem) in enumerate(queue):
+                queue[idx] = (0, lastdue, pollitem)
+        self._event.set()
+        return True
+
     def run(self, started_callback):
         '''start poll loop
 
@@ -222,7 +238,7 @@ class Poller(PollerBase):
             heapify(queue)
         started_callback() # signal end of startup
         nregular = len(self.queues[REGULAR])
-        while not self._stopped.is_set():
+        while not self._stopped:
             due = float('inf')
             for _ in range(nregular):
                 due = min(self.poll_next(DYNAMIC), self.poll_next(REGULAR))
@@ -231,10 +247,12 @@ class Poller(PollerBase):
             due = min(due, self.poll_next(DYNAMIC), self.poll_next(SLOW))
             delay = due - time.time()
             if delay > 0:
-                self._stopped.wait(delay)
+                self._event.wait(delay)
+                self._event.clear()
 
     def stop(self):
-        self._stopped.set()
+        self._event.set()
+        self._stopped = True
 
     def __bool__(self):
         '''is there any poll item?'''
diff --git a/secop/stringio.py b/secop/stringio.py
index 73ab5a2..4ac9860 100644
--- a/secop/stringio.py
+++ b/secop/stringio.py
@@ -73,12 +73,14 @@ class StringIO(Communicator):
                 argument=ArrayOf(StringType()), result= ArrayOf(StringType()))
     }
 
+    _reconnectCallbacks = None
+
     def earlyInit(self):
         self._stream = None
         self._lock = threading.RLock()
         self._end_of_line = self.end_of_line.encode(self.encoding)
         self._connect_error = None
-        self._last_error = 'not connected'
+        self._last_error = None
 
     def createConnection(self):
         """create connection
@@ -111,7 +113,7 @@ class StringIO(Communicator):
         if timeout is None or timeout < 0:
             raise ValueError('illegal timeout %r' % timeout)
         if not self.is_connected:
-            raise CommunicationSilentError(self._last_error)
+            raise CommunicationSilentError(self._last_error or 'not connected')
         self._stream.settimeout(timeout)
         try:
             reply = self._stream.recv(4096)
@@ -164,6 +166,7 @@ class StringIO(Communicator):
             if self._last_error:
                 self.log.info('connected')
                 self._last_error = 'connected'
+                self.callCallbacks()
                 return Done
         except Exception as e:
             if str(e) == self._last_error:
@@ -192,6 +195,26 @@ class StringIO(Communicator):
                     raise CommunicationFailedError('bad response: %s does not match %s' %
                         (reply, regexp))
 
+    def registerReconnectCallback(self, name, func):
+        """register reconnect callback
+
+        if the callback fails or returns False, it is cleared
+        """
+        if self._reconnectCallbacks is None:
+            self._reconnectCallbacks = {name: func}
+        else:
+            self._reconnectCallbacks[name] = func
+
+    def callCallbacks(self):
+        for key, cb in list(self._reconnectCallbacks.items()):
+            try:
+                removeme = not cb()
+            except Exception as e:
+                self.log.error('callback: %s' % e)
+                removeme = True
+            if removeme:
+                self._reconnectCallbacks.pop(key)
+
     def do_communicate(self, command):
         '''send a command and receive a reply
 
diff --git a/test/test_poller.py b/test/test_poller.py
index 7b985b3..e23a0b7 100644
--- a/test/test_poller.py
+++ b/test/test_poller.py
@@ -73,7 +73,10 @@ class Event:
         artime.sleep(max(0,timeout))
 
     def set(self):
-        self.flag=True
+        self.flag = True
+
+    def clear(self):
+        self.flag = False
 
     def is_set(self):
         return self.flag
@@ -198,7 +201,7 @@ def test_Poller(modules):
         assert len(pollTable) == 1
         poller = pollTable[(Poller, 'common_iodev')]
         artime.stop = poller.stop
-        poller._stopped = Event() # patch Event.wait
+        poller._event = Event() # patch Event.wait
 
         assert (sum(count.values()) > 0) == bool(poller)
 
@@ -233,6 +236,7 @@ def test_Poller(modules):
             for module in modules:
                 for pobj in module.parameters.values():
                     if pobj.poll:
+                        assert pobj.cnt > 0
                         assert pobj.maxspan <= maxspan[pobj.polltype] * 1.1
                         assert (pobj.cnt + 1) * pobj.interval >= total * 0.99
                         assert abs(pobj.span - pobj.interval) < 0.01