diff --git a/dsmr_parser/protocol.py b/dsmr_parser/protocol.py
index 6342e9d..2ee9c32 100644
--- a/dsmr_parser/protocol.py
+++ b/dsmr_parser/protocol.py
@@ -9,8 +9,7 @@ from serial_asyncio import create_serial_connection
 from . import telegram_specifications
 from .exceptions import ParseError
 from .parsers import TelegramParserV2_2, TelegramParserV4
-from .serial import (SERIAL_SETTINGS_V2_2, SERIAL_SETTINGS_V4,
-                     is_end_of_telegram, is_start_of_telegram, TelegramBuffer)
+from .serial import (SERIAL_SETTINGS_V2_2, SERIAL_SETTINGS_V4,TelegramBuffer)
 
 
 def create_dsmr_protocol(dsmr_version, telegram_callback, loop=None):
@@ -81,7 +80,9 @@ class DSMRProtocol(asyncio.Protocol):
         data = data.decode('ascii')
         self.log.debug('received data: %s', data)
         self.telegram_buffer.put(data)
-        map(self.handle_telegram, self.telegram_buffer.get_all())
+
+        for telegram in self.telegram_buffer.get_all():
+            self.handle_telegram(telegram)
 
     def connection_lost(self, exc):
         """Stop when connection is lost."""
diff --git a/dsmr_parser/serial.py b/dsmr_parser/serial.py
index 5ed809e..54128b3 100644
--- a/dsmr_parser/serial.py
+++ b/dsmr_parser/serial.py
@@ -32,22 +32,6 @@ SERIAL_SETTINGS_V4 = {
 }
 
 
-def is_start_of_telegram(line):
-    """
-    :param bytes line: series of bytes representing a line.
-        Example: b'/KFM5KAIFA-METER\r\n'
-    """
-    return line.startswith('/')
-
-
-def is_end_of_telegram(line):
-    """
-    :param bytes line: series of bytes representing a line.
-        Example: b'!7B05\r\n'
-    """
-    return line.startswith('!')
-
-
 class SerialReader(object):
     PORT_KEY = 'port'
 
@@ -123,8 +107,8 @@ class AsyncSerialReader(SerialReader):
 
 class TelegramBuffer(object):
     """
-    Used as a buffer for a stream or telegram data. Returns telegram from buffer
-    when complete.
+    Used as a buffer for a stream of telegram data. Constructs full telegram
+    strings from the buffered data and returns it.
     """
 
     def __init__(self):
@@ -132,7 +116,7 @@ class TelegramBuffer(object):
 
     def get_all(self):
         """
-        Remove complete telegrams from buffer and yield them
+        Remove complete telegrams from buffer and yield them.
         :rtype generator:
         """
         for telegram in self._find_telegrams():
@@ -160,7 +144,7 @@ class TelegramBuffer(object):
 
     def _find_telegrams(self):
         """
-        Find complete telegrams from buffer from  start ('/') till ending
+        Find complete telegrams in buffer from  start ('/') till ending
         checksum ('!AB12\r\n').
         :rtype: list
         """
diff --git a/test/test_parse_v2_2.py b/test/test_parse_v2_2.py
index eaaa7ee..26c6d49 100644
--- a/test/test_parse_v2_2.py
+++ b/test/test_parse_v2_2.py
@@ -1,6 +1,6 @@
 import unittest
 
-from .example_telegrams import TELEGRAM_V2_2
+from test.example_telegrams import TELEGRAM_V2_2
 from dsmr_parser.parsers import TelegramParserV2_2
 from dsmr_parser import telegram_specifications
 from dsmr_parser import obis_references as obis
diff --git a/test/test_parse_v4_2.py b/test/test_parse_v4_2.py
index a7904fc..1048f87 100644
--- a/test/test_parse_v4_2.py
+++ b/test/test_parse_v4_2.py
@@ -4,7 +4,7 @@ import unittest
 
 import pytz
 
-from .example_telegrams import TELEGRAM_V4_2
+from test.example_telegrams import TELEGRAM_V4_2
 from dsmr_parser import obis_references as obis
 from dsmr_parser import telegram_specifications
 from dsmr_parser.exceptions import InvalidChecksumError, ParseError