diff --git a/apps/grgsm_trx b/apps/grgsm_trx
index 7886b12..670d919 100755
--- a/apps/grgsm_trx
+++ b/apps/grgsm_trx
@@ -43,7 +43,10 @@
 
 	# PHY specific
 	phy_sample_rate = 2000000
-	phy_gain = 30
+	phy_tx_antenna = "TX/RX"
+	phy_rx_antenna = "RX2"
+	phy_rx_gain = 30
+	phy_tx_gain = 10
 	phy_args = ""
 	phy_ppm = 0
 
@@ -57,7 +60,9 @@
 	def run(self):
 		# Init Radio interface
 		self.radio = radio_if(self.phy_args, self.phy_sample_rate,
-			self.phy_gain, self.phy_ppm, self.remote_addr, self.base_port)
+			self.phy_rx_gain, self.phy_tx_gain, self.phy_ppm,
+			self.phy_rx_antenna, self.phy_tx_antenna,
+			self.remote_addr, self.base_port)
 
 		# Power measurement emulation
 		# Noise: -120 .. -105
@@ -90,24 +95,28 @@
 
 		# TRX specific
 		s += " TRX interface specific\n" \
-			 "  -s --remote-addr  Set remote address (default 127.0.0.1)\n" \
+			 "  -i --remote-addr  Set remote address (default 127.0.0.1)\n" \
 			 "  -p --base-port    Set base port number (default 5700)\n\n"
 
 		# PHY specific
 		s += " Radio interface specific\n" \
 			 "  -a --device-args  Set device arguments\n" \
-			 "  -s --sample-rate  Set PHY sample rate (default 2000000)\n" \
-			 "  -g --gain         Set PHY gain (default 30)\n" \
-			 "     --ppm          Set PHY frequency correction (default 0)\n"
+			 "  -s --sample-rate  Set sample rate (default 2000000)\n" \
+			 "  -g --rx-gain      Set RX gain (default 30)\n" \
+			 "  -G --tx-gain      Set TX gain (default 10)\n" \
+			 "     --rx-antenna   Set RX antenna (default RX2)\n" \
+			 "     --tx-antenna   Set TX antenna (default TX/RX)\n" \
+			 "     --ppm          Set frequency correction (default 0)\n"
 
 		print(s)
 
 	def parse_argv(self):
 		try:
 			opts, args = getopt.getopt(sys.argv[1:],
-				"a:p:i:s:g:h",
+				"i:p:a:s:g:G:h",
 				["help", "remote-addr=", "base-port=", "device-args=",
-				"gain=", "sample-rate=", "ppm="])
+				"sample-rate=", "rx-gain=", "tx-gain=", "ppm=",
+				"rx-antenna", "tx-antenna"])
 		except getopt.GetoptError as err:
 			# Print(help and exit)
 			self.print_help()
@@ -132,10 +141,16 @@
 			# PHY specific
 			elif o in ("-a", "--device-args"):
 				self.phy_args = v
-			elif o in ("-g", "--gain"):
-				self.phy_gain = int(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)
 
diff --git a/python/trx/radio_if.py b/python/trx/radio_if.py
index a6cd23c..0164cde 100644
--- a/python/trx/radio_if.py
+++ b/python/trx/radio_if.py
@@ -45,18 +45,17 @@
 	trx_started = False
 	fc_set = False
 
-	def __init__(self, phy_args, phy_sample_rate, phy_gain, phy_ppm,
+	def __init__(self, phy_args, phy_sample_rate,
+			phy_rx_gain, phy_tx_gain, phy_ppm,
+			phy_rx_antenna, phy_tx_antenna,
 			trx_remote_addr, trx_base_port):
-		print("[i] Init Radio interface")
 
-		# TRX block specific variables
-		self.trx_remote_addr = trx_remote_addr
-		self.trx_base_port = trx_base_port
+		print("[i] Init Radio interface")
 
 		# PHY specific variables
 		self.samp_rate = phy_sample_rate
-		self.device_args = phy_args
-		self.gain = phy_gain
+		self.rx_gain = phy_rx_gain
+		self.tx_gain = phy_tx_gain
 		self.ppm = phy_ppm
 
 		gr.top_block.__init__(self, "GR-GSM TRX")
@@ -65,8 +64,7 @@
 		##################################################
 		# PHY Definition
 		##################################################
-		self.phy = osmosdr.source(
-			args = "numchan=%d %s" % (1, self.device_args))
+		self.phy = osmosdr.source(args = "numchan=%d %s" % (1, phy_args))
 
 		self.phy.set_bandwidth(250e3 + abs(self.shiftoff), 0)
 		self.phy.set_center_freq(shift_fc, 0)
@@ -75,10 +73,10 @@
 		self.phy.set_iq_balance_mode(2, 0)
 		self.phy.set_dc_offset_mode(2, 0)
 		self.phy.set_gain_mode(False, 0)
-		self.phy.set_gain(self.gain, 0)
+		self.phy.set_gain(self.rx_gain, 0)
 		self.phy.set_if_gain(20, 0)
 		self.phy.set_bb_gain(20, 0)
-		self.phy.set_antenna("", 0)
+		self.phy.set_antenna(phy_rx_antenna, 0)
 
 		##################################################
 		# GR-GSM Magic
@@ -99,7 +97,7 @@
 		self.gsm_ts_filter.set_policy(grgsm.FILTER_POLICY_DROP_ALL)
 
 		self.gsm_trx_burst_if = grgsm.trx_burst_if(
-			self.trx_remote_addr, str(self.trx_base_port))
+			trx_remote_addr, str(trx_base_port))
 
 		##################################################
 		# Connections