diff --git a/dsmr_parser/clients/protocol.py b/dsmr_parser/clients/protocol.py
index e5e6a66..9b4536e 100644
--- a/dsmr_parser/clients/protocol.py
+++ b/dsmr_parser/clients/protocol.py
@@ -91,7 +91,7 @@ class DSMRProtocol(asyncio.Protocol):
         self.transport = transport
         self.log.debug('connected')
         self._active = False
-        if self._keep_alive_interval:
+        if self.loop and self._keep_alive_interval:
             self.loop.call_later(self._keep_alive_interval, self.keep_alive)
 
     def data_received(self, data):
@@ -108,10 +108,12 @@ class DSMRProtocol(asyncio.Protocol):
         if self._active:
             self.log.debug('keep-alive checked')
             self._active = False
-            self.loop.call_later(self._keep_alive_interval, self.keep_alive)
+            if self.loop:
+                self.loop.call_later(self._keep_alive_interval, self.keep_alive)
         else:
             self.log.warning('keep-alive check failed')
-            self.transport.close()
+            if self.transport:
+                self.transport.close()
 
     def connection_lost(self, exc):
         """Stop when connection is lost."""
diff --git a/test/test_protocol.py b/test/test_protocol.py
index 2fb14e0..c298d5c 100644
--- a/test/test_protocol.py
+++ b/test/test_protocol.py
@@ -5,7 +5,7 @@ import unittest
 from dsmr_parser import obis_references as obis
 from dsmr_parser import telegram_specifications
 from dsmr_parser.parsers import TelegramParser
-from dsmr_parser.clients.protocol import DSMRProtocol
+from dsmr_parser.clients.protocol import create_dsmr_protocol
 
 
 TELEGRAM_V2_2 = (
@@ -35,9 +35,10 @@ TELEGRAM_V2_2 = (
 class ProtocolTest(unittest.TestCase):
 
     def setUp(self):
-        telegram_parser = TelegramParser(telegram_specifications.V2_2)
-        self.protocol = DSMRProtocol(None, telegram_parser,
-                                     telegram_callback=Mock())
+        new_protocol, _ = create_dsmr_protocol('2.2',
+                                               telegram_callback=Mock(),
+                                               keep_alive_interval=1)
+        self.protocol = new_protocol()
 
     def test_complete_packet(self):
         """Protocol should assemble incoming lines into complete packet."""
@@ -52,3 +53,23 @@ class ProtocolTest(unittest.TestCase):
 
         assert float(telegram[obis.GAS_METER_READING].value) == 1.001
         assert telegram[obis.GAS_METER_READING].unit == 'm3'
+
+    def test_receive_packet(self):
+        """Protocol packet reception."""
+
+        mock_transport = Mock()
+        self.protocol.connection_made(mock_transport)
+        assert not self.protocol._active
+
+        self.protocol.data_received(TELEGRAM_V2_2.encode('ascii'))
+        assert self.protocol._active
+
+        # 1st call of keep_alive resets 'active' flag
+        self.protocol.keep_alive()
+        assert not self.protocol._active
+
+        # 2nd call of keep_alive should close the transport
+        self.protocol.keep_alive()
+        assert mock_transport.close.called_once()
+
+        self.protocol.connection_lost(None)