diff --git a/requirements.txt b/requirements.txt
new file mode 100644
index 0000000..a2ae8b7
--- /dev/null
+++ b/requirements.txt
@@ -0,0 +1,5 @@
+serial
+modbus_tk
+configparser
+pymodbus
+paho-mqtt
diff --git a/sdm630-mqtt.conf b/sdm630-mqtt.conf
index 548f728..2e058fe 100644
--- a/sdm630-mqtt.conf
+++ b/sdm630-mqtt.conf
@@ -5,8 +5,15 @@ keepalive=10
 topic_prefix=/sdm630
 
 [sdm630]
-host=localhost
-port=5002
 regfile=registers.csv
 num_meters=1
 id1=1
+connection_type=tcp
+
+[tcp]
+host=localhost
+port=5002
+
+[rs485]
+PORT=/dev/usbserial/sdm630
+BAUDRATE=9600
diff --git a/sdm630-mqtt.py b/sdm630-mqtt.py
old mode 100644
new mode 100755
index 19e25ea..e95cb74
--- a/sdm630-mqtt.py
+++ b/sdm630-mqtt.py
@@ -1,7 +1,7 @@
 #!/usr/bin/env python3
 # -*- coding: utf_8 -*-
 
-from sdm630 import SDM630
+from sdm630 import *
 
 import sys
 import serial
@@ -28,7 +28,7 @@ def publish(topic,value):
 config = ConfigParser.ConfigParser()
 confread = config.read(CONFIG_FILE)
 logging.info("Read config {}".format(confread))
-logging.info("Opening port {}".format(config.get("sdm630","port")))
+
 
 logging.info("Connecting to MQTT server...")
 mqclient = mqtt.Client()
@@ -45,12 +45,22 @@ def publish(topic,value):
 logging.info("Setup...")
 num_meters = config.getint("sdm630","num_meters")
 meters = []
+connection_type = config.get("sdm630", "connection_type")
+
 for i in range(num_meters):
-	meter = SDM630(config.get("sdm630","host"),
-		config.get("sdm630","port"),
-		config.getint("sdm630","id"+str(i+1)),
-		config.get("sdm630","regfile"))
-	meter.connect()
+	if connection_type == 'tcp':
+		logging.info("Opening port {}".format(config.get("tcp","port")))
+		meter = SDM630TCP(host=config.get("tcp","host"),
+			port=config.get("tcp","port"),
+			aid=config.getint("sdm630","id"+str(i+1)),
+			regfile=config.get("sdm630", "regfile"))
+	elif connection_type == 'rs485':
+		logging.info("Opening port {}".format(config.get("rs485","port")))
+		meter = SDM630RS485(config.get("rs485","PORT"),
+			config.getint("rs485","BAUDRATE"),
+			config.getint("sdm630","id"+str(i+1)),
+			regfile=config.get("sdm630", "regfile"))
+
 	meters.append(meter)
 
 logging.info("Entering endless loop")
diff --git a/sdm630.py b/sdm630.py
index 027a07a..1f206a6 100644
--- a/sdm630.py
+++ b/sdm630.py
@@ -1,28 +1,25 @@
 # -*- coding: utf_8 -*-
 
 from pymodbus.client.sync import ModbusTcpClient
+from pymodbus.client.sync import ModbusSerialClient
 from pymodbus.payload import BinaryPayloadDecoder
 from pymodbus.constants import Endian
+
 import serial
 import time
 import csv
 
 class SDM630(object):
-	def __init__(self,host,port,aid,regfile):
+	def __init__(self, regfile):
+		self.__fill_registers__(regfile)
+	
+	def __fill_registers__(self, regfile):
 		self.registers = {}
 		with open(regfile) as regs:
 			reader = csv.reader(regs,delimiter=';')
 			for line in reader:
 				self.registers[line[1]] = int(line[0],base=16)
-		self.aid = aid
-		self.host = host
-		self.port = port
-
-	def connect(self):
-		self.master = ModbusTcpClient(host=self.host,port=self.port)
-#		self.master.set_timeout(1.0)
-#		self.master.set_verbose(True)
-
+	
 		
 	def __getattr__(self,attr):
 		if attr == "voltx3":
@@ -46,3 +43,27 @@ def read_registers(self,addr,count):
 			return decoder.decode_32bit_float()
 		return tuple(decoder.decode_32bit_float() for _ in range(count))
 
+# connecting using tcp
+class SDM630TCP(SDM630):
+	def __init__(self,host,port,aid,regfile):
+		SDM630.__init__(self,regfile)
+
+		self.aid = aid
+		self.host = host
+		self.port = port
+		
+		self.master = ModbusTcpClient(host=self.host,port=self.port)
+
+
+# connecting using serial port
+class SDM630RS485(SDM630):
+	def __init__(self, port, baudrate, aid, regfile):
+		SDM630.__init__(self,regfile)
+
+		self.port = port
+		self.baudrate = baudrate
+		self.aid = aid
+
+		self.master = ModbusSerialClient("rtu", port=self.port, baudrate=self.baudrate, timeout=1)
+
+
diff --git a/test.py b/test.py
old mode 100644
new mode 100755
index 85fea6d..1106b06
--- a/test.py
+++ b/test.py
@@ -8,9 +8,11 @@
 
 from struct import *
 import serial
+import sys
 import modbus_tk
 import modbus_tk.defines as cst
 from modbus_tk import modbus_rtu
+import configparser
 
 def read_float(arrRegs):
     reg1 = arrRegs[1]
@@ -32,17 +34,31 @@ def bcdDigits(chars):
                 return
             yield val
 
-PORT = '/dev/usbserial/sdm630'
 SLAVE = 1
 
 def main():
     """main"""
     logger = modbus_tk.utils.create_logger("console")
 
+    CONFIG_FILE = 'sdm630-mqtt.conf'
+    if ((len(sys.argv) == 3) and sys.argv[1] == '-c'):
+        CONFIG_FILE = sys.argv[2]
+
+    config = configparser.ConfigParser()
+    config.read(CONFIG_FILE)
+    rs485 = config['rs485']
+    PORT=rs485.get('PORT')
+    BAUDRATE=rs485.getint('BAUDRATE', 9600)
+    BYTESIZE=rs485.getint('BYTESIZE', 8)
+    PARITY=rs485.get('PARITY', 'N')
+    STOPBITS=rs485.getint('STOPBITS', 1)
+    XONXOFF=rs485.getint('XONXOFF', 0)
+    DSRDTR=rs485.getboolean('DSRDTR', True)
+
     try:
         #Connect to the slave
         master = modbus_rtu.RtuMaster(
-            serial.Serial(port=PORT, baudrate=9600, bytesize=8, parity='N', stopbits=1, xonxoff=0, dsrdtr=True)
+            serial.Serial(port=PORT, baudrate=BAUDRATE, bytesize=BYTESIZE, parity=PARITY, stopbits=STOPBITS, xonxoff=XONXOFF, dsrdtr=DSRDTR)
         )
         master.set_timeout(1.0)
 #        master.set_verbose(True)