diff --git a/lib/model/sdp/connection.py b/lib/model/sdp/connection.py
index d1a3ee5c8d..55f9c3f115 100644
--- a/lib/model/sdp/connection.py
+++ b/lib/model/sdp/connection.py
@@ -732,9 +732,10 @@ def _open(self):
 
             if self._is_connected:
                 self._connection_attempts = 0
+                self._setup_listener()
+                # only call on_connect callback after listener is set up
                 if self._params[PLUGIN_ATTR_CB_ON_CONNECT]:
                     self._params[PLUGIN_ATTR_CB_ON_CONNECT](self)
-                self._setup_listener()
                 return True
             else:
                 self.logger.debug(f'sleeping {self._params[PLUGIN_ATTR_CONN_CYCLE]} seconds before next connection attempt')
diff --git a/lib/model/smartdeviceplugin.py b/lib/model/smartdeviceplugin.py
index 20f145a59b..81f89f7080 100644
--- a/lib/model/smartdeviceplugin.py
+++ b/lib/model/smartdeviceplugin.py
@@ -208,7 +208,7 @@ def __init__(self, sh, logger=None, **kwargs):
         # possibly initialize additional (overwrite _set_device_defaults)
         self._set_device_defaults()
 
-        # save modified value for passing to SDPCommands
+        # save modified value for ing to SDPCommands
         self._parameters['custom_patterns'] = self._custom_patterns
 
         # set/update plugin configuration
@@ -338,13 +338,6 @@ def resume(self, by=None):
             if self._suspend_item is not None:
                 self._suspend_item(False, self.get_fullname())
             self.connect()
-            if self._connection.connected():
-                if self._resume_initial_read:
-                    # make sure to read again on resume (if configured)
-                    self._initial_value_read_done = False
-                    self.read_initial_values()
-                if not SDP_standalone:
-                    self._create_cyclic_scheduler()
 
             # call user-defined resume actions
             self.on_resume()
@@ -787,8 +780,8 @@ def send_command(self, command, value=None, return_result=False, **kwargs):
         elif isinstance(reply_pattern, list):
             return_list = []
             for r in reply_pattern:
-                 if '(' not in r and '{' not in r:
-                     return_list.append(r)
+                if '(' not in r and '{' not in r:
+                    return_list.append(r)
             reply_pattern = return_list if return_list else value
             resend_info = {'command': resend_command, 'returnvalue': reply_pattern, 'read_cmd': read_cmd}
         # if reply pattern does not expect a specific value, use value as expected reply
@@ -1039,7 +1032,13 @@ def _send(self, data_dict, **kwargs):
 
     def on_connect(self, by=None):
         """ callback if connection is made. """
-        pass
+        if self._connection.connected():
+            if self._resume_initial_read:
+                # make sure to read again on resume (if configured)
+                self._initial_value_read_done = False
+                self.read_initial_values()
+            if not SDP_standalone:
+                self._create_cyclic_scheduler()
 
     def on_disconnect(self, by=None):
         """ callback if connection is broken. """
@@ -1221,7 +1220,7 @@ def _read_cyclic_values(self):
                 self._cyclic_update_active = False
 
                 # reconnect
-                if not self._parameters.get(PLUGIN_ATTR_CONN_AUTO_RECONN, False):
+                if self._parameters.get(PLUGIN_ATTR_CONN_AUTO_RECONN, False):
                     time.sleep(1)
                     self.connect()
             else:
@@ -1674,7 +1673,9 @@ def create_item(self, node, node_name, parent, path, indent, gpath, gpathlist, c
                             rg_list = [rg_list]
                         for entry in rg_list:
                             grps.append(entry.get('name'))
-                    item[ITEM_ATTR_GROUP + '@instance'] = grps
+                    # only create read_groups if they actually exist
+                    if grps:
+                        item[ITEM_ATTR_GROUP + '@instance'] = grps
 
                 # item attributes
                 if ia_node: