diff --git a/rpOsci.py b/rpOsci.py
index e1f27a5ae570a51c722c3d04563ae84c4e13f0d4..20e7cd3fbed23e184e150f4edfa40a903c3a63ae 100755
--- a/rpOsci.py
+++ b/rpOsci.py
@@ -85,6 +85,9 @@ class rpControl(QMainWindow, Ui_MCPHA):
     def __init__(self):
         super(rpControl, self).__init__()
         # !gq additions
+        # get command line arguments
+        self.parse_args()
+        # set physical units (for axis labels)
         self.get_physical_units()
         # !gq end
         self.setupUi(self)
@@ -96,13 +99,9 @@ class rpControl(QMainWindow, Ui_MCPHA):
         self.timers = self.status[:4].view(np.uint64)
         # create tabs
         self.log = LogDisplay()
-#        self.hst1 = HstDisplay(self, self.log, 0)
-#        self.hst2 = HstDisplay(self, self.log, 1)
         self.osc = OscDisplay(self, self.log)
         self.gen = GenDisplay(self, self.log)
         self.tabWidget.addTab(self.log, "Messages")
-#        self.tabWidget.addTab(self.hst1, "Spectrum histogram 1")
-#        self.tabWidget.addTab(self.hst2, "Spectrum histogram 2")
         self.tabWidget.addTab(self.osc, "Oscilloscope")
         self.tabWidget.addTab(self.gen, "Pulse generator")
         # configure controls
@@ -133,18 +132,19 @@ class rpControl(QMainWindow, Ui_MCPHA):
         self.readTimer = QTimer(self)   # for readout 
         self.readTimer.timeout.connect(self.read_osci)
 
-        # get command line arguments
-        # !gq additions
-        self.parse_args()
-        # set argument options
+       # !gq additions
+        # transfer command-line arguments to gui
         self.osc.levelValue.setValue(self.trigger_level)
+        self.osc.autoButton.setChecked(self.trigger_mode)
+        self.osc.ch2Button.setChecked(self.trigger_source)
+        self.osc.fallingButton.setChecked(self.trigger_slope)
         # automatically connect
         if self.ip_address is not None:
             self.addrValue.setText(self.ip_address)
             self.start()
         else:    
             self.addrValue.setStyleSheet("color: darkorange")
-        # !gq end
+      # !gq end
 
         
     # !gq get command line arguments
@@ -156,12 +156,23 @@ class rpControl(QMainWindow, Ui_MCPHA):
             help='trigger level in ADC counts')
         parser.add_argument('-i', '--interval', type=int, default=100,
             help='interval for readout (in ms)')
-
+        parser.add_argument('-s', '--sample_size', type=int, default=100000,
+            help='size of waveform sample')
+        parser.add_argument('-p', '--pretrigger_fraction', type=float, default=0.05,
+            help='pretrigger fraction')
         args = parser.parse_args()
-        self.trigger_level = args.trigger_level
+        # all relevant parameters are here
         self.ip_address = args.connect_ip
+        self.sample_size = args.sample_size
+        self.pretrigger_fraction = args.pretrigger_fraction
         self.readInterval = args.interval
-        
+        # 
+        self.trigger_level = args.trigger_level
+        # other parameters
+        self.trigger_mode = 0   # normal, 1 = auto
+        self.trigger_source = 0 # channel 1, 1 = channel 2
+        self.trigger_slope = 0  # rising, 1 = falling 
+                
     def get_physical_units(self):
         """get physical units corresponding to ADC units and channel numbers
         """
@@ -235,7 +246,7 @@ class rpControl(QMainWindow, Ui_MCPHA):
         # check status
         self.read_status()
         if not self.read_data(self.status):
-            print("failed to read status")
+            self.log.print("failed to read status")
             return
         if self.osc_waiting and not self.status[8] & 1:
             self.command(20, 0, 0)
@@ -244,7 +255,7 @@ class rpControl(QMainWindow, Ui_MCPHA):
                 self.reset_osc()
                 self.start_osc()
             else:
-                print("failed to read oscilloscope data")
+                self.log.print("failed to read oscilloscope data")
                 return
 
     def reset_osc(self):        
@@ -327,8 +338,8 @@ class OscDisplay(QWidget, Ui_OscDisplay):
         # initialize variables
         self.rpControl = rpControl
         self.log = log
-        self.pre = 5000
-        self.tot = 100000
+        self.tot = self.rpControl.sample_size
+        self.pre = self.rpControl.pretrigger_fraction * self.tot
         self.buffer = np.zeros(self.tot * 2, np.int16)
         # create figure
         self.figure = Figure()
@@ -423,18 +434,25 @@ class OscDisplay(QWidget, Ui_OscDisplay):
     def start(self):
         if self.rpControl.idle:
             return
-        self.rpControl.set_trg_mode(self.autoButton.isChecked())
-        self.rpControl.set_trg_source(self.ch2Button.isChecked())
-        self.rpControl.set_trg_slope(self.fallingButton.isChecked())
-        self.rpControl.set_trg_level(self.levelValue.value())
+        # extract parameters from gui
+        self.trg_mode = int(self.autoButton.isChecked())
+        self.trg_source = int(self.ch2Button.isChecked())
+        self.trg_slope = int(self.fallingButton.isChecked())
+        self.trg_level = self.levelValue.value()
+
+        self.rpControl.set_trg_mode(self.trg_mode)
+        self.rpControl.set_trg_source(self.trg_source)
+        self.rpControl.set_trg_slope(self.trg_slope)
+        self.rpControl.set_trg_level(self.trg_level)
         self.rpControl.set_osc_pre(self.pre)
         self.rpControl.set_osc_tot(self.tot)
         self.rpControl.reset_osc()
         self.rpControl.start_osc()
+        self.log.print("oscilloscope started")
+        # toggle startButton: turn to 'Stop'
         self.startButton.setText("Stop")
         self.startButton.clicked.disconnect()
         self.startButton.clicked.connect(self.stop)
-        self.log.print("oscilloscope started")
 
     def stop(self):
         self.rpControl.stop_osc()