diff --git a/apps/grgsm_trx b/apps/grgsm_trx
index 6efed07..d57c979 100755
--- a/apps/grgsm_trx
+++ b/apps/grgsm_trx
@@ -4,6 +4,7 @@
 # GR-GSM based transceiver
 #
 # (C) 2016-2018 by Vadim Yanitskiy <axilirator@gmail.com>
+# (C) 2017-2018 by Piotr Krysik <ptrkrysik@gmail.com>
 #
 # All Rights Reserved
 #
@@ -22,9 +23,10 @@
 # 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 
 import signal
-import getopt
 import sys
 
+from argparse import ArgumentParser
+from argparse import ArgumentTypeError
 from gnuradio import eng_notation
 
 from grgsm.trx import ctrl_if_bb
@@ -33,31 +35,25 @@
 
 COPYRIGHT = \
 	"Copyright (C) 2016-2018 by Vadim Yanitskiy <axilirator@gmail.com>\n" \
-	"Copyright (C) 2017 by Piotr Krysik <ptrkrysik@gmail.com>\n" \
+	"Copyright (C) 2017-2018 by Piotr Krysik <ptrkrysik@gmail.com>\n" \
 	"License GPLv2+: GNU GPL version 2 or later " \
 	"<http://gnu.org/licenses/gpl.html>\n" \
 	"This is free software: you are free to change and redistribute it.\n" \
 	"There is NO WARRANTY, to the extent permitted by law.\n"
 
 class Application:
-	# Application variables
-	remote_addr = "127.0.0.1"
-	bind_addr = "0.0.0.0"
-	base_port = 6700
-
-	# PHY specific
-	phy_sample_rate = radio_if.SAMPLE_RATE
-	phy_freq_offset_hz = None
-	phy_tx_antenna = "TX/RX"
-	phy_rx_antenna = "RX2"
-	phy_rx_gain = 30
-	phy_tx_gain = 10
-	phy_args = ""
-	phy_ppm = 0
-
-	def __init__(self):
-		self.print_copyright()
-		self.parse_argv()
+	def __init__(self, argv):
+		self.remote_addr = argv.remote_addr
+		self.bind_addr = argv.bind_addr
+		self.base_port = argv.base_port
+		self.phy_args = argv.args
+		self.phy_sample_rate = argv.sample_rate
+		self.phy_rx_gain = argv.rx_gain
+		self.phy_tx_gain = argv.tx_gain
+		self.phy_rx_antenna = argv.rx_antenna
+		self.phy_tx_antenna = argv.tx_antenna
+		self.phy_freq_offset_hz = argv.freq_offset
+		self.phy_ppm = argv.ppm
 
 		# Set up signal handlers
 		signal.signal(signal.SIGINT, self.sig_handler)
@@ -95,97 +91,64 @@
 		print("[i] Shutting down...")
 		self.radio.shutdown()
 
-	def print_copyright(self):
-		print(COPYRIGHT)
-
-	def print_help(self):
-		s  = " Usage: " + sys.argv[0] + " [options]\n\n" \
-			 " Some help...\n" \
-			 "  -h --help         this text\n\n"
-
-		# TRX specific
-		s += " TRX interface specific\n" \
-			 "  -i --remote-addr  Set remote address (default %s)\n" \
-			 "  -b --bind-addr    Set bind address (default %s)\n" \
-			 "  -p --base-port    Set base port number (default %d)\n\n"
-
-		# PHY specific
-		s += " Radio interface specific\n" \
-			 "  -a --device-args  Set device arguments\n" \
-			 "  -s --sample-rate  Set sample rate\n" \
-			 "  -g --rx-gain      Set RX gain (default %d)\n" \
-			 "  -G --tx-gain      Set TX gain (default %d)\n" \
-			 "     --rx-antenna   Set RX antenna (default %s)\n" \
-			 "     --tx-antenna   Set TX antenna (default %s)\n" \
-			 "     --freq-offset  Shift baseband freq. (e.g. -500M)\n" \
-			 "     --ppm          Set frequency correction (default %d)\n"
-
-		print(s % (
-			self.remote_addr,
-			self.bind_addr,
-			self.base_port,
-			self.phy_rx_gain,
-			self.phy_tx_gain,
-			self.phy_rx_antenna,
-			self.phy_tx_antenna,
-			self.phy_ppm))
-
-	def parse_argv(self):
-		try:
-			opts, args = getopt.getopt(sys.argv[1:],
-				"i:b:p:a:s:g:G:h",
-				["help", "remote-addr=", "bind-addr=", "base-port=",
-				"device-args=", "sample-rate=", "rx-gain=", "tx-gain=",
-				"ppm=", "rx-antenna=", "tx-antenna=", "freq-offset="])
-		except getopt.GetoptError as err:
-			# Print(help and exit)
-			self.print_help()
-			print("[!] " + str(err))
-			sys.exit(2)
-
-		for o, v in opts:
-			if o in ("-h", "--help"):
-				self.print_help()
-				sys.exit(2)
-
-			# TRX specific
-			elif o in ("-i", "--remote-addr"):
-				self.remote_addr = v
-			elif o in ("-b", "--bind-addr"):
-				self.bind_addr = v
-			elif o in ("-p", "--base-port"):
-				if int(v) >= 0 and int(v) <= 65535:
-					self.base_port = int(v)
-				else:
-					print("[!] The port number should be in range [0-65536]")
-					sys.exit(2)
-
-			# PHY specific
-			elif o in ("-a", "--device-args"):
-				self.phy_args = v
-			elif o in ("-s", "--sample-rate"):
-				self.phy_sample_rate = int(v)
-			elif o in ("-g", "--rx-gain"):
-				self.phy_rx_gain = int(v)
-			elif o in ("-G", "--tx-gain"):
-				self.phy_tx_gain = int(v)
-			elif o in ("--rx-antenna"):
-				self.phy_rx_antenna = v
-			elif o in ("--tx-antenna"):
-				self.phy_tx_antenna = v
-			elif o in ("--ppm"):
-				self.phy_ppm = int(v)
-			elif o in ("--freq-offset"):
-				# Convert /\d+(\.\d+)?(M|k)?/ to Hz
-				offset_hz = eng_notation.str_to_num(v)
-				self.phy_freq_offset_hz = offset_hz
-
 	def sig_handler(self, signum, frame):
 		print("Signal %d received" % signum)
 		if signum is signal.SIGINT:
 			self.shutdown()
 			sys.exit(0)
 
+def eng_float(value):
+	try:
+		return eng_notation.str_to_num(value)
+	except:
+		raise ArgumentTypeError("invalid engineering notation "
+			"value: {0}".format(value))
+
+def parse_argv():
+	parser = ArgumentParser(prog = "grgsm_trx")
+
+	# TRX interface specific
+	parser.add_argument("-i", "--remote-addr",
+		dest = "remote_addr", type = str, default = "127.0.0.1",
+		help = "Set remote address (default %(default)s)")
+	parser.add_argument("-b", "--bind-addr",
+		dest = "bind_addr", type = str, default = "0.0.0.0",
+		help = "Set bind address (default %(default)s)")
+	parser.add_argument("-p", "--base_port",
+		dest = "base_port", type = int, default = 6700,
+		help = "Set base port number (default %(default)s)")
+
+	# PHY specific
+	parser.add_argument("-a", "--args",
+		dest = "args", type = str, default = "",
+		help = "Set device arguments")
+	parser.add_argument("-s", "--sample-rate",
+		dest = "sample_rate", type = eng_float,
+		default = radio_if.SAMPLE_RATE,
+		help = "Set samp_rate (default %(default)s)")
+	parser.add_argument("-g", "--rx-gain",
+		dest = "rx_gain", type = float, default = 30,
+		help = "Set RX gain (default %(default)s)")
+	parser.add_argument("-G", "--tx-gain",
+		dest = "tx_gain", type = float, default = 10,
+		help = "Set TX gain (default %(default)s)")
+	parser.add_argument("--rx-antenna",
+		dest = "rx_antenna", type = str, default = "RX2",
+		help = "Set RX antenna (default %(default)s)")
+	parser.add_argument("--tx-antenna",
+		dest = "tx_antenna", type = str, default = "TX/RX",
+		help = "Set TX antenna (default %(default)s)")
+	parser.add_argument("--freq-offset",
+		dest = "freq_offset", type = eng_float, default = 0,
+		help = "Shift baseband freq. (e.g. -500M)")
+	parser.add_argument("--ppm",
+		dest = "ppm", type = float, default = 0,
+		help = "Set frequency correction (default %(default)s)")
+
+	return parser.parse_args()
+
 if __name__ == '__main__':
-	app = Application()
+	print(COPYRIGHT)
+	argv = parse_argv()
+	app = Application(argv)
 	app.run()