diff --git a/connection.cpp b/connection.cpp
index 8cc1a7f..9789e5a 100644
--- a/connection.cpp
+++ b/connection.cpp
@@ -29,9 +29,17 @@
 #include "connection.h"
 
 
+#define TMC_LAN_TIMEOUT   5000
+
+#define MAX_CMD_LEN     (255)
+#define MAX_RESP_LEN    (1024 * 1024 * 2)
+
+
 int tmc_connection_type;
 
-struct tmcdev *usb_tmcdev;
+struct tmcdev *tmc_device;
+
+QTcpSocket *sck;
 
 
 
@@ -39,9 +47,9 @@ struct tmcdev * tmc_open_usb(const char *device)
 {
   tmc_connection_type = 0;
 
-  usb_tmcdev = tmcdev_open(device);
+  tmc_device = tmcdev_open(device);
 
-  return usb_tmcdev;
+  return tmc_device;
 }
 
 
@@ -49,38 +57,292 @@ void tmc_close(void)
 {
   if(tmc_connection_type == 0)
   {
-    tmcdev_close(usb_tmcdev);
+    tmcdev_close(tmc_device);
 
-    usb_tmcdev = NULL;
+    tmc_device = NULL;
+  }
+  else
+  {
+    if(sck != NULL)
+    {
+      sck->abort();
+
+      delete sck;
+
+      sck = NULL;
+    }
+
+    if(tmc_device != NULL)
+    {
+      free(tmc_device->hdrbuf);
+
+      free(tmc_device);
+
+      tmc_device = NULL;
+    }
   }
 }
 
 
-int tmc_write(const char *msg)
+int tmc_write(const char *cmd)
 {
+  int qry=0;
+
+  char buf[MAX_CMD_LEN + 16],
+       str[256];
+
   if(tmc_connection_type == 0)
   {
-    return tmcdev_write(usb_tmcdev, msg);
+    return tmcdev_write(tmc_device, cmd);
+  }
+  else
+  {
+    if(sck == NULL)
+    {
+      return -1;
+    }
+
+    if(strlen(cmd) > MAX_CMD_LEN)
+    {
+      printf("tmc_lan error: command too long\n");
+
+      return -1;
+    }
+
+    if(strlen(cmd) < 2)
+    {
+      printf("tmc_lan error: command too short\n");
+
+      return -1;
+    }
+
+    if(cmd[strlen(cmd) - 1] == '?')
+    {
+      qry = 1;
+    }
+
+    strncpy(buf, cmd, MAX_CMD_LEN);
+
+    buf[MAX_CMD_LEN] = 0;
+
+    strcat(buf, "\n");
+
+    if(!(!strncmp(buf, ":TRIG:STAT?", 11) ||
+        !strncmp(buf, ":TRIG:SWE?", 10) ||
+        !strncmp(buf, ":WAV:DATA?", 10) ||
+        !strncmp(buf, ":WAV:MODE NORM", 14) ||
+        !strncmp(buf, ":WAV:FORM BYTE", 14) ||
+        !strncmp(buf, ":WAV:SOUR CHAN", 14) ||
+        !strncmp(buf, ":TRIG:SWE?", 10) ||
+        !strncmp(buf, ":ACQ:SRAT?", 10) ||
+        !strncmp(buf, ":ACQ:MDEP?", 10) ||
+        !strncmp(buf, ":MEAS:COUN:VAL?", 15)))
+    {
+      printf("tmc_lan write: %s", buf);
+    }
+
+    sck->write(buf);
+
+    if(sck->waitForBytesWritten(TMC_LAN_TIMEOUT) == false)
+    {
+      return -1;
+    }
+
+    if(!qry)
+    {
+      for(int i=0; i<20; i++)
+      {
+        usleep(50000);
+
+        sck->write("*OPC?\n");
+
+        if(sck->waitForBytesWritten(TMC_LAN_TIMEOUT) == false)
+        {
+          return -1;
+        }
+
+        if(sck->waitForReadyRead(TMC_LAN_TIMEOUT) == false)
+        {
+          return -1;
+        }
+
+        if(sck->read(str, 128) == 2)
+        {
+          if(str[0] == '1')
+          {
+            break;
+          }
+        }
+      }
+    }
+
+    return strlen(cmd);
   }
 
   return -1;
 }
 
 
+/*
+ * TMC Blockheader ::= #NXXXXXX: is used to describe
+ * the length of the data stream, wherein, # is the start denoter of
+ * the data stream; N is less than or equal to 9; the N figures
+ * followed N represents the length of the data stream in bytes.
+ * For example, #9001152054. Wherein, N is 9 and 001152054
+ * represents that the data stream contains 1152054 bytes
+ * effective data.
+ * Reading from the file descriptor blocks,
+ * there is a timeout of 5000 milli-Sec.
+ */
 int tmc_read(void)
 {
+  int size, size2, len;
+
+  char blockhdr[32];
+
   if(tmc_connection_type == 0)
   {
-    return tmcdev_read(usb_tmcdev);
+    return tmcdev_read(tmc_device);
+  }
+  else
+  {
+    if(sck == NULL)
+    {
+      return -1;
+    }
+
+    tmc_device->hdrbuf[0] = 0;
+
+    tmc_device->sz = 0;
+
+    size = 0;
+
+    while(1)
+    {
+      if(sck->waitForReadyRead(TMC_LAN_TIMEOUT) == false)
+      {
+        return -1;
+      }
+
+      size += sck->read(tmc_device->hdrbuf + size, MAX_RESP_LEN - size);
+
+      if(tmc_device->hdrbuf[size - 1] == '\n')
+      {
+        break;
+      }
+    }
+
+    if((size < 2) || (size > MAX_RESP_LEN))
+    {
+      tmc_device->hdrbuf[0] = 0;
+
+      tmc_device->buf[0] = 0;
+
+      return -1;
+    }
+
+    if(size >= 0)
+    {
+      tmc_device->hdrbuf[size] = 0;
+    }
+
+    if(size == 0)
+    {
+      return 0;
+    }
+
+    if(tmc_device->hdrbuf[0] != '#')
+    {
+      if(tmc_device->hdrbuf[size - 1] == '\n')
+      {
+        tmc_device->hdrbuf[--size] = 0;
+      }
+
+      tmc_device->buf = tmc_device->hdrbuf;
+
+      tmc_device->sz = size;
+
+      return tmc_device->sz;
+    }
+
+    strncpy(blockhdr, tmc_device->hdrbuf, 16);
+
+    len = blockhdr[1] - '0';
+
+    if((len < 1) || (len > 9))
+    {
+      blockhdr[31] = 0;
+
+      return -1;
+    }
+
+    blockhdr[len + 2] = 0;
+
+    size2 = atoi(blockhdr + 2);
+
+    size--;  // remove the last character
+
+    if(size < size2)
+    {
+      blockhdr[31] = 0;
+
+      return -1;
+    }
+
+    tmc_device->buf = tmc_device->hdrbuf + len + 2;
+
+    tmc_device->sz = size2;
+
+    return tmc_device->sz;
   }
 
   return -1;
 }
 
 
+struct tmcdev * tmc_open_lan(const char *address)
+{
+  tmc_connection_type = 1;
+
+  sck = new QTcpSocket;
+
+  sck->connectToHost(address, 5555);
+
+  if(sck->waitForConnected(TMC_LAN_TIMEOUT) == false)
+  {
+    sck->abort();
+    delete sck;
+    sck = NULL;
+    return NULL;
+  }
+
+  tmc_device = (struct tmcdev *)calloc(1, sizeof(struct tmcdev));
+  if(tmc_device == NULL)
+  {
+    sck->abort();
+    delete sck;
+    sck = NULL;
+    return NULL;
+  }
+
+  tmc_device->hdrbuf = (char *)calloc(1, MAX_RESP_LEN + 1024);
+  if(tmc_device->hdrbuf == NULL)
+  {
+    free(tmc_device);
+    sck->abort();
+    delete sck;
+    sck = NULL;
+    return NULL;
+  }
+
+  tmc_device->buf = tmc_device->hdrbuf;
+
+  return tmc_device;
+}
+
+
 
 
 
 
 
-
diff --git a/connection.h b/connection.h
index 657bfd3..9fb5f4b 100644
--- a/connection.h
+++ b/connection.h
@@ -29,16 +29,31 @@
 #ifndef DSR_CONNECTION_H
 #define DSR_CONNECTION_H
 
+#include <QtGlobal>
+#include <QApplication>
+#include <QObject>
+#include <QTcpSocket>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <locale.h>
+#include <time.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
 
 #include "global.h"
 #include "tmc_dev.h"
 #include "utils.h"
 
 
-struct tmcdev * tmc_open_usb(const char *device);
+
+struct tmcdev * tmc_open_usb(const char *);
 void tmc_close(void);
 int tmc_write(const char *);
 int tmc_read(void);
+struct tmcdev * tmc_open_lan(const char *);
 
 
 
diff --git a/dsremote.pro b/dsremote.pro
index 6ee0f23..567d52c 100644
--- a/dsremote.pro
+++ b/dsremote.pro
@@ -11,6 +11,7 @@ CONFIG += static
 CONFIG += largefile
 
 QT += widgets
+QT += network
 
 QMAKE_CXXFLAGS += -Wextra -Wshadow -Wformat-nonliteral -Wformat-security -Wtype-limits -Wfatal-errors
 
diff --git a/global.h b/global.h
index bad7b14..2a9906d 100644
--- a/global.h
+++ b/global.h
@@ -31,7 +31,7 @@
 
 
 #define PROGRAM_NAME          "DSRemote"
-#define PROGRAM_VERSION       "0.11_1506271103"
+#define PROGRAM_VERSION       "0.20_1506271641"
 
 #define MAX_PATHLEN            4096
 
diff --git a/interface.cpp b/interface.cpp
index 1d108ce..dc0f5c2 100644
--- a/interface.cpp
+++ b/interface.cpp
@@ -987,6 +987,12 @@ void UI_Mainwindow::vertScaleDialChanged(int new_pos)
 
   tmc_write(str);
 
+  tmc_write(":TRIG:EDG:LEV?");
+
+  tmc_read();
+
+  devparms.triggeredgelevel[chn] = atof(device->buf);
+
   old_pos = new_pos;
 
   waveForm->update();
diff --git a/mainwindow.cpp b/mainwindow.cpp
index caa2bea..5d0c2a1 100644
--- a/mainwindow.cpp
+++ b/mainwindow.cpp
@@ -44,9 +44,9 @@ void UI_Mainwindow::open_connection()
 {
   int n;
 
-  char str[1024],
-       dev_str[128] = {""},
-       resp_str[1024],
+  char str[1024] = {""},
+       dev_str[256] = {""},
+       resp_str[1024] = {""},
        *ptr;
 
   QSettings settings;
@@ -74,7 +74,7 @@ void UI_Mainwindow::open_connection()
 
   if(devparms.connectiontype == 0)  // USB
   {
-    strcpy(dev_str, settings.value("connection/device").toString().toLocal8Bit().data());
+    strcpy(dev_str, settings.value("connection/device").toString().toLatin1().data());
 
     if(!strcmp(dev_str, ""))
     {
@@ -93,6 +93,20 @@ void UI_Mainwindow::open_connection()
 
   if(devparms.connectiontype == 1)  // LAN
   {
+    strcpy(dev_str, settings.value("connection/ip").toString().toLatin1().data());
+
+    if(!strcmp(dev_str, ""))
+    {
+      sprintf(str, "No IP address set");
+      goto OUT_ERROR;
+    }
+
+    device = tmc_open_lan(dev_str);
+    if(device == NULL)
+    {
+      sprintf(str, "Can not open connection to %s", dev_str);
+      goto OUT_ERROR;
+    }
   }
 
   if(tmc_write("*IDN?") != 5)
@@ -2383,6 +2397,12 @@ void UI_Mainwindow::chan_scale_plus()
 
   tmc_write(str);
 
+  tmc_write(":TRIG:EDG:LEV?");
+
+  tmc_read();
+
+  devparms.triggeredgelevel[chn] = atof(device->buf);
+
   waveForm->update();
 }
 
@@ -2447,6 +2467,12 @@ void UI_Mainwindow::chan_scale_minus()
 
   tmc_write(str);
 
+  tmc_write(":TRIG:EDG:LEV?");
+
+  tmc_read();
+
+  devparms.triggeredgelevel[chn] = atof(device->buf);
+
   waveForm->update();
 }
 
diff --git a/mainwindow.h b/mainwindow.h
index bddb0fa..9da53d4 100644
--- a/mainwindow.h
+++ b/mainwindow.h
@@ -32,6 +32,7 @@
 
 #include <QtGlobal>
 #include <QApplication>
+#include <QObject>
 #include <QtGui>
 #include <QWidget>
 #include <QMainWindow>
diff --git a/settings_dialog.cpp b/settings_dialog.cpp
index 495b1ae..d331590 100644
--- a/settings_dialog.cpp
+++ b/settings_dialog.cpp
@@ -103,7 +103,19 @@ UI_settings_window::UI_settings_window(QWidget *parnt)
 
   comboBox1->setCurrentIndex(dev_str[11] - '0');
 
-  QObject::connect(applyButton,    SIGNAL(clicked()),     this, SLOT(applyButtonClicked()));
+  if(mainwindow->devparms.connected)
+  {
+    usbRadioButton->setEnabled(false);
+    lanRadioButton->setEnabled(false);
+    ipLineEdit->setEnabled(false);
+    comboBox1->setEnabled(false);
+    applyButton->setEnabled(false);
+  }
+  else
+  {
+    QObject::connect(applyButton,    SIGNAL(clicked()),     this, SLOT(applyButtonClicked()));
+  }
+
   QObject::connect(cancelButton,   SIGNAL(clicked()),     this, SLOT(close()));
 
   exec();
diff --git a/tmc_dev.c b/tmc_dev.c
index 002e8e5..800dcee 100644
--- a/tmc_dev.c
+++ b/tmc_dev.c
@@ -54,7 +54,7 @@ struct tmcdev * tmcdev_open(const char *device)
     return NULL;
   }
 
-  dev->hdrbuf = calloc(1, MAX_RESP_LEN + 1024);
+  dev->hdrbuf = (char *)calloc(1, MAX_RESP_LEN + 1024);
   if(dev->hdrbuf == NULL)
   {
     free(dev);