diff --git a/pjon_python/base_client.py b/pjon_python/base_client.py
index 664471c..a19edbb 100644
--- a/pjon_python/base_client.py
+++ b/pjon_python/base_client.py
@@ -1,3 +1,4 @@
+import sys
 import time
 import serial
 import logging
@@ -48,7 +49,15 @@ def __init__(self, bus_addr=1, com_port=None, baud=115200, write_timeout=0.005,
             if com_port not in available_com_ports:
                 raise EnvironmentError("specified COM port is one of available ports: %s" % available_com_ports)
 
-            self._serial = serial.Serial(com_port, baud, write_timeout=write_timeout, timeout=timeout)
+            if sys.platform.startswith('win'):
+                self._serial = serial.Serial(com_port, baud, write_timeout=write_timeout, timeout=timeout)
+            elif sys.platform.startswith('linux') or sys.platform.startswith('cygwin'):
+                self._serial = serial.Serial(com_port, baud, writeTimeout=write_timeout, timeout=timeout)
+            elif sys.platform.startswith('darwin'):
+                self._serial = serial.Serial(com_port, baud, writeTimeout=write_timeout, timeout=timeout)
+            else:
+                raise EnvironmentError('Unsupported platform')
+
         else:
             if transport is None:
                 self._serial = fakeserial.Serial(com_port, baud, write_timeout=write_timeout, timeout=timeout,
diff --git a/setup.py b/setup.py
index 2525324..e9931c2 100644
--- a/setup.py
+++ b/setup.py
@@ -6,13 +6,13 @@
 setup(
   name='pjon_python',
   packages=['pjon_python', 'pjon_python.protocol', 'pjon_python.strategies', 'pjon_python.utils'],
-  version='4.2.5',
+  version='4.2.6',
   description='Python implementation of the PJON communication protocol.',
   long_description=read_md('./README.rst'),
   author='Zbigniew Zasieczny',
   author_email='z.zasieczny@gmail.com',
   url='https://github.com/Girgitt/PJON-python',
-  download_url='https://github.com/Girgitt/PJON-python/tarball/4.2.5',
+  download_url='https://github.com/Girgitt/PJON-python/tarball/4.2.6',
   keywords=['PJON', 'multimaster', 'serial', 'RS485', 'arduino'],
   classifiers=[],
 )
\ No newline at end of file