diff --git a/src/HikvisionAttendanceManager.App/DbToDeviceView.xaml.cs b/src/HikvisionAttendanceManager.App/DbToDeviceView.xaml.cs
deleted file mode 100644
index f69474c..0000000
--- a/src/HikvisionAttendanceManager.App/DbToDeviceView.xaml.cs
+++ /dev/null
@@ -1,136 +0,0 @@
-using System.Collections.ObjectModel;
-using System.Windows;
-using System.Windows.Controls;
-using HikvisionAttendanceManager.App.Models;
-using HikvisionAttendanceManager.App.Services;
-
-namespace HikvisionAttendanceManager.App;
-
-public partial class DbToDeviceView : UserControl
-{
-    private readonly DeviceService _devices = new();
-    private readonly AttendanceMachineUserRepository _machineUsers = new();
-    private readonly AttendanceMachineFaceTemplateRepository _faceTemplates = new();
-    private readonly TemplateSyncService _service;
-    private readonly ObservableCollection<SelectableMachineUser> _rows = [];
-    private bool _initialized;
-
-    public DbToDeviceView()
-    {
-        InitializeComponent();
-        _service = new TemplateSyncService(new HikvisionIsapiClient(), _machineUsers, _faceTemplates, new OperationHistoryService());
-        UsersGrid.ItemsSource = _rows;
-        UpdateUsersEmptyState();
-    }
-
-    public async Task InitializeAsync()
-    {
-        if (_initialized) return;
-        _initialized = true;
-        await RefreshAsync();
-    }
-
-    public async Task RefreshAsync()
-    {
-        var originalContent = RefreshButton.Content;
-        try
-        {
-            RefreshButton.IsEnabled = false;
-            RefreshButton.Content = "Refreshing...";
-            SourceCombo.SelectedItem = null;
-            TargetCombo.SelectedItem = null;
-            _rows.Clear();
-            UpdateUsersEmptyState();
-            ProgressCard.Visibility = Visibility.Collapsed;
-            ProgressBar.Value = 0;
-            ProgressText.Text = "";
-            CounterText.Text = "";
-            UsersGrid.Items.Refresh();
-            var devices = await _devices.LoadUnifiedAsync();
-            SourceCombo.ItemsSource = devices;
-            TargetCombo.ItemsSource = devices;
-        }
-        finally
-        {
-            RefreshButton.IsEnabled = true;
-            RefreshButton.Content = originalContent;
-        }
-    }
-
-    private async void Refresh_Click(object sender, RoutedEventArgs e) => await RefreshAsync();
-
-    private void SourceChanged(object sender, SelectionChangedEventArgs e)
-    {
-        _rows.Clear();
-        UpdateUsersEmptyState();
-    }
-
-    private async void LoadUsers_Click(object sender, RoutedEventArgs e)
-    {
-        if (SourceCombo.SelectedItem is not Device source) { MessageBox.Show("Select a source machine."); return; }
-        _rows.Clear();
-        var users = await _machineUsers.GetActiveByMachineAsync(source.MachineId, CancellationToken.None);
-        foreach (var user in users)
-        {
-            var template = await _faceTemplates.TryGetActiveAsync(user.SerialNumber, CancellationToken.None);
-            var hasFace = template?.Template is { Length: > 0 } && HikvisionIsapiClient.IsUploadableFaceTemplate(template.Template);
-            _rows.Add(new SelectableMachineUser(user.SerialNumber, user.EmployeeName, hasFace));
-        }
-
-        UpdateUsersEmptyState();
-    }
-
-    private void SelectAll_Click(object sender, RoutedEventArgs e)
-    {
-        foreach (var row in _rows) row.IsSelected = true;
-        UsersGrid.Items.Refresh();
-    }
-
-    private void ClearSelection_Click(object sender, RoutedEventArgs e)
-    {
-        foreach (var row in _rows) row.IsSelected = false;
-        UsersGrid.Items.Refresh();
-    }
-
-    private void UpdateUsersEmptyState()
-    {
-        UsersEmptyState.Visibility = _rows.Count == 0 ? Visibility.Visible : Visibility.Collapsed;
-    }
-
-    private async void Transfer_Click(object sender, RoutedEventArgs e)
-    {
-        if (SourceCombo.SelectedItem is not Device source || TargetCombo.SelectedItem is not Device target)
-        {
-            MessageBox.Show("Select source and target machines.");
-            return;
-        }
-        if (string.Equals(source.MachineId, target.MachineId, StringComparison.OrdinalIgnoreCase) &&
-            string.Equals(source.IpAddress, target.IpAddress, StringComparison.OrdinalIgnoreCase))
-        {
-            MessageBox.Show("Source and target must be different devices.");
-            return;
-        }
-
-        var selected = _rows.Where(r => r.IsSelected).Select(r => r.SerialNumber).ToList();
-        if (selected.Count == 0) { MessageBox.Show("Select at least one user."); return; }
-
-        ProgressCard.Visibility = Visibility.Visible;
-        var progress = new Progress<UserSyncProgress>(p =>
-        {
-            ProgressBar.Maximum = Math.Max(1, p.Total);
-            ProgressBar.Value = p.Completed;
-            ProgressText.Text = $"{p.Completed}/{p.Total} · {p.CurrentEmployee} · {p.CurrentOperation}";
-            CounterText.Text = $"Users: {p.Created} · Faces: {p.FacesUploaded} · Skipped: {p.Skipped} · Failed: {p.Failed}";
-        });
-        try
-        {
-            var entry = await _service.DbToDeviceAsync(source, target, selected, progress, CancellationToken.None);
-            ProgressText.Text = $"Completed — {entry.Status}";
-            CounterText.Text = entry.Context;
-        }
-        catch (Exception ex)
-        {
-            MessageBox.Show(ex.Message, "DB → Device", MessageBoxButton.OK, MessageBoxImage.Error);
-        }
-    }
-}
diff --git a/src/HikvisionAttendanceManager.App/DbToDeviceView.xaml b/src/HikvisionAttendanceManager.App/DeviceToDeviceView.xaml
similarity index 65%
rename from src/HikvisionAttendanceManager.App/DbToDeviceView.xaml
rename to src/HikvisionAttendanceManager.App/DeviceToDeviceView.xaml
index 2b8d6ca..33d8496 100644
--- a/src/HikvisionAttendanceManager.App/DbToDeviceView.xaml
+++ b/src/HikvisionAttendanceManager.App/DeviceToDeviceView.xaml
@@ -1,4 +1,4 @@
-<UserControl x:Class="HikvisionAttendanceManager.App.DbToDeviceView"
+<UserControl x:Class="HikvisionAttendanceManager.App.DeviceToDeviceView"
              xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
              xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
     <UserControl.Resources>
@@ -171,8 +171,8 @@
         <StackPanel Margin="0,2,0,0">
             <DockPanel LastChildFill="False">
                 <StackPanel DockPanel.Dock="Left">
-                    <TextBlock Text="DB -> Device" Style="{StaticResource PageTitle}"/>
-                    <TextBlock Text="Transfer users registered to a source machine in DB onto a different target Hikvision device (JPEG face templates only)." Style="{StaticResource PageSubtitle}"/>
+                    <TextBlock Text="Device → Device" Style="{StaticResource PageTitle}"/>
+                    <TextBlock Text="Transfer users from one Hikvision device to another." Style="{StaticResource PageSubtitle}"/>
                 </StackPanel>
                 <Button x:Name="RefreshButton" Content="↻ Refresh" Style="{StaticResource HeaderRefreshButton}" DockPanel.Dock="Right" VerticalAlignment="Top" Click="Refresh_Click"/>
             </DockPanel>
@@ -187,20 +187,43 @@
                             <ColumnDefinition Width="*"/>
                         </Grid.ColumnDefinitions>
                         <StackPanel Grid.Column="0">
-                            <TextBlock Text="Source Machine (DB)" Style="{StaticResource FieldLabel}"/>
+                            <TextBlock Text="Source Machine" Style="{StaticResource FieldLabel}"/>
                             <ComboBox x:Name="SourceCombo" Style="{StaticResource ModernComboBox}" SelectionChanged="SourceChanged"/>
+                            <StackPanel Orientation="Horizontal" Margin="0,10,0,0">
+                                <Ellipse x:Name="SourceStatusDot" Width="8" Height="8" Fill="#9CA3AF" VerticalAlignment="Center"/>
+                                <TextBlock x:Name="SourceStatusText" Margin="8,0,0,0" FontSize="12" Foreground="#64748B" Text="Select a device"/>
+                            </StackPanel>
                         </StackPanel>
                         <StackPanel Grid.Column="2">
                             <TextBlock Text="Target Machine" Style="{StaticResource FieldLabel}"/>
-                            <ComboBox x:Name="TargetCombo" Style="{StaticResource ModernComboBox}"/>
+                            <ComboBox x:Name="TargetCombo" Style="{StaticResource ModernComboBox}" SelectionChanged="TargetChanged"/>
+                            <StackPanel Orientation="Horizontal" Margin="0,10,0,0">
+                                <Ellipse x:Name="TargetStatusDot" Width="8" Height="8" Fill="#9CA3AF" VerticalAlignment="Center"/>
+                                <TextBlock x:Name="TargetStatusText" Margin="8,0,0,0" FontSize="12" Foreground="#64748B" Text="Select a device"/>
+                            </StackPanel>
                         </StackPanel>
                     </Grid>
 
-                    <StackPanel Orientation="Horizontal" Margin="0,24,0,0">
-                        <Button Style="{StaticResource OutlineButton}" Click="LoadUsers_Click">
+                    <Border x:Name="SourceInfoBanner" Visibility="Collapsed" Margin="0,18,0,0" Padding="14,10" CornerRadius="6" BorderThickness="1">
+                        <TextBlock x:Name="SourceInfoText" TextWrapping="Wrap" FontSize="12"/>
+                    </Border>
+
+                    <TextBlock x:Name="SameDeviceWarning" Visibility="Collapsed" Margin="0,14,0,0" FontSize="12" Foreground="#DC2626"
+                               Text="Source and target devices must be different."/>
+
+                    <TextBlock x:Name="TargetOfflineWarning" Visibility="Collapsed" Margin="0,10,0,0" FontSize="12" Foreground="#DC2626"
+                               Text="Target device is not connected. Connect the target device before transferring users."/>
+                </StackPanel>
+            </Border>
+
+            <Border Style="{StaticResource ModernCard}" Margin="0,0,0,16">
+                <StackPanel>
+                    <TextBlock Text="USERS" Style="{StaticResource SectionLabel}"/>
+                    <StackPanel Orientation="Horizontal" Margin="0,18,0,0">
+                        <Button x:Name="LoadUsersButton" Style="{StaticResource OutlineButton}" Click="LoadUsers_Click">
                             <StackPanel Orientation="Horizontal">
                                 <Path Width="15" Height="15" Stretch="Uniform" Stroke="#2563EB" StrokeThickness="1.7" StrokeStartLineCap="Round" StrokeEndLineCap="Round" StrokeLineJoin="Round" Fill="Transparent" Margin="0,0,8,0" Data="M 3 4 C 3 2.9 11 2.9 11 4 V 12 C 11 13.1 3 13.1 3 12 Z M 3 4 C 3 5.1 11 5.1 11 4 M 3 8 C 3 9.1 11 9.1 11 8"/>
-                                <TextBlock Text="Load Users from Source DB"/>
+                                <TextBlock Text="Load Users"/>
                             </StackPanel>
                         </Button>
                         <Button Style="{StaticResource NeutralButton}" Margin="16,0,0,0" Click="SelectAll_Click">
@@ -216,63 +239,65 @@
                             </StackPanel>
                         </Button>
                     </StackPanel>
+
+                    <TextBlock x:Name="LoadStatusText" Margin="0,14,0,0" FontSize="12" Foreground="#475569" TextWrapping="Wrap"/>
+                    <TextBlock x:Name="SelectionCountText" Margin="0,8,0,14" FontSize="12" Foreground="#1F2A44" FontWeight="SemiBold" Text="0 user(s) loaded • 0 selected"/>
+
+                    <Grid>
+                        <DataGrid x:Name="UsersGrid"
+                                  AutoGenerateColumns="False"
+                                  CanUserAddRows="False"
+                                  IsReadOnly="False"
+                                  HeadersVisibility="Column"
+                                  RowHeight="42"
+                                  MinHeight="220"
+                                  MaxHeight="280"
+                                  BorderBrush="#DDE5F0"
+                                  BorderThickness="1"
+                                  GridLinesVisibility="Horizontal"
+                                  HorizontalGridLinesBrush="#EEF2F7"
+                                  Background="White"
+                                  RowBackground="White"
+                                  AlternatingRowBackground="White"
+                                  ColumnHeaderStyle="{StaticResource UsersGridHeaderStyle}"
+                                  CellStyle="{StaticResource UsersGridCellStyle}">
+                            <DataGrid.Columns>
+                                <DataGridTemplateColumn Width="90" MinWidth="80" IsReadOnly="False">
+                                    <DataGridTemplateColumn.Header>
+                                        <StackPanel Orientation="Horizontal">
+                                            <CheckBox Click="SelectAll_Click" VerticalAlignment="Center" Margin="0,0,8,0"/>
+                                            <TextBlock Text="Select"/>
+                                        </StackPanel>
+                                    </DataGridTemplateColumn.Header>
+                                    <DataGridTemplateColumn.CellTemplate>
+                                        <DataTemplate>
+                                            <Grid HorizontalAlignment="Stretch">
+                                                <CheckBox IsChecked="{Binding IsSelected, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" HorizontalAlignment="Center" VerticalAlignment="Center"/>
+                                            </Grid>
+                                        </DataTemplate>
+                                    </DataGridTemplateColumn.CellTemplate>
+                                </DataGridTemplateColumn>
+                                <DataGridTextColumn Header="Employee / Serial" Binding="{Binding SerialNumber}" Width="140" MinWidth="110" ElementStyle="{StaticResource UsersTextCell}" IsReadOnly="True"/>
+                                <DataGridTextColumn Header="Name" Binding="{Binding EmployeeName}" Width="*" MinWidth="200" ElementStyle="{StaticResource UsersTextCell}" IsReadOnly="True"/>
+                                <DataGridTextColumn Header="Source" Binding="{Binding SourceDisplay}" Width="90" MinWidth="70" ElementStyle="{StaticResource UsersTextCell}" IsReadOnly="True"/>
+                                <DataGridTextColumn Header="Face" Binding="{Binding FaceDisplay}" Width="70" MinWidth="60" ElementStyle="{StaticResource UsersTextCell}" IsReadOnly="True"/>
+                            </DataGrid.Columns>
+                        </DataGrid>
+
+                        <StackPanel x:Name="UsersEmptyState" HorizontalAlignment="Center" VerticalAlignment="Center" IsHitTestVisible="False">
+                            <Border Width="68" Height="68" CornerRadius="7" Background="#EEF4FB" HorizontalAlignment="Center">
+                                <Grid>
+                                    <Path Width="35" Height="35" Stretch="Uniform" Stroke="#A7BCE0" StrokeThickness="1.9" StrokeStartLineCap="Round" StrokeEndLineCap="Round" Fill="Transparent" HorizontalAlignment="Center" VerticalAlignment="Center" Data="M 11 13 A 5 5 0 1 1 11 3 A 5 5 0 0 1 11 13 M 3 24 C 4.2 17 17.8 17 19 24 M 1 29 H 20 M 1 34 H 13 M 17 33 H 19"/>
+                                </Grid>
+                            </Border>
+                            <TextBlock Text="No users loaded." Margin="0,16,0,0" Foreground="#10203D" FontSize="13" FontWeight="SemiBold" HorizontalAlignment="Center"/>
+                            <TextBlock Text="Select a source machine, then click &quot;Load Users&quot;." Margin="0,8,0,0" Foreground="#718096" FontSize="12" HorizontalAlignment="Center"/>
+                        </StackPanel>
+                    </Grid>
                 </StackPanel>
             </Border>
 
-            <Border Style="{StaticResource ModernCard}" Padding="16" Margin="0,0,0,16">
-                <Grid>
-                    <DataGrid x:Name="UsersGrid"
-                              AutoGenerateColumns="False"
-                              CanUserAddRows="False"
-                              IsReadOnly="False"
-                              HeadersVisibility="Column"
-                              RowHeight="42"
-                              MinHeight="220"
-                              MaxHeight="280"
-                              BorderBrush="#DDE5F0"
-                              BorderThickness="1"
-                              GridLinesVisibility="Horizontal"
-                              HorizontalGridLinesBrush="#EEF2F7"
-                              Background="White"
-                              RowBackground="White"
-                              AlternatingRowBackground="White"
-                              ColumnHeaderStyle="{StaticResource UsersGridHeaderStyle}"
-                              CellStyle="{StaticResource UsersGridCellStyle}">
-                        <DataGrid.Columns>
-                            <DataGridTemplateColumn Width="110" MinWidth="95" IsReadOnly="False">
-                                <DataGridTemplateColumn.Header>
-                                    <StackPanel Orientation="Horizontal">
-                                        <CheckBox Click="SelectAll_Click" VerticalAlignment="Center" Margin="0,0,8,0"/>
-                                        <TextBlock Text="Select"/>
-                                    </StackPanel>
-                                </DataGridTemplateColumn.Header>
-                                <DataGridTemplateColumn.CellTemplate>
-                                    <DataTemplate>
-                                        <Grid HorizontalAlignment="Stretch">
-                                            <CheckBox IsChecked="{Binding IsSelected, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" HorizontalAlignment="Center" VerticalAlignment="Center"/>
-                                        </Grid>
-                                    </DataTemplate>
-                                </DataGridTemplateColumn.CellTemplate>
-                            </DataGridTemplateColumn>
-                            <DataGridTextColumn Header="Serial" Binding="{Binding SerialNumber}" Width="140" MinWidth="110" ElementStyle="{StaticResource UsersTextCell}" IsReadOnly="True"/>
-                            <DataGridTextColumn Header="Name" Binding="{Binding EmployeeName}" Width="*" MinWidth="260" ElementStyle="{StaticResource UsersTextCell}" IsReadOnly="True"/>
-                            <DataGridCheckBoxColumn Header="Face in DB" Binding="{Binding HasFaceTemplate, Mode=OneWay}" Width="120" MinWidth="100" IsReadOnly="True"/>
-                        </DataGrid.Columns>
-                    </DataGrid>
-
-                    <StackPanel x:Name="UsersEmptyState" HorizontalAlignment="Center" VerticalAlignment="Center" IsHitTestVisible="False">
-                        <Border Width="68" Height="68" CornerRadius="7" Background="#EEF4FB" HorizontalAlignment="Center">
-                            <Grid>
-                                <Path Width="35" Height="35" Stretch="Uniform" Stroke="#A7BCE0" StrokeThickness="1.9" StrokeStartLineCap="Round" StrokeEndLineCap="Round" Fill="Transparent" HorizontalAlignment="Center" VerticalAlignment="Center" Data="M 11 13 A 5 5 0 1 1 11 3 A 5 5 0 0 1 11 13 M 3 24 C 4.2 17 17.8 17 19 24 M 1 29 H 20 M 1 34 H 13 M 17 33 H 19"/>
-                            </Grid>
-                        </Border>
-                        <TextBlock Text="No users loaded." Margin="0,16,0,0" Foreground="#10203D" FontSize="13" FontWeight="SemiBold" HorizontalAlignment="Center"/>
-                        <TextBlock Text="Click &quot;Load Users from Source DB&quot; to fetch users." Margin="0,8,0,0" Foreground="#718096" FontSize="12" HorizontalAlignment="Center"/>
-                    </StackPanel>
-                </Grid>
-            </Border>
-
-            <Button Style="{StaticResource TransferButton}" Click="Transfer_Click">
+            <Button x:Name="TransferButton" Style="{StaticResource TransferButton}" IsEnabled="False" Click="Transfer_Click">
                 <StackPanel Orientation="Horizontal">
                     <Path Width="15" Height="15" Stretch="Uniform" Stroke="White" StrokeThickness="1.7" StrokeStartLineCap="Round" StrokeEndLineCap="Round" StrokeLineJoin="Round" Fill="Transparent" Margin="0,0,8,0" Data="M 8 13 V 4 M 4 8 L 8 4 L 12 8 M 3 13 V 16 H 13 V 13"/>
                     <TextBlock Text="Transfer Selected to Target"/>
diff --git a/src/HikvisionAttendanceManager.App/DeviceToDeviceView.xaml.cs b/src/HikvisionAttendanceManager.App/DeviceToDeviceView.xaml.cs
new file mode 100644
index 0000000..c02ef62
--- /dev/null
+++ b/src/HikvisionAttendanceManager.App/DeviceToDeviceView.xaml.cs
@@ -0,0 +1,405 @@
+using System.Collections.ObjectModel;
+using System.ComponentModel;
+using System.Windows;
+using System.Windows.Controls;
+using System.Windows.Media;
+using HikvisionAttendanceManager.App.Models;
+using HikvisionAttendanceManager.App.Services;
+
+namespace HikvisionAttendanceManager.App;
+
+public partial class DeviceToDeviceView : UserControl
+{
+    private readonly DeviceService _devices = new();
+    private readonly DeviceConnectionService _connections = new();
+    private readonly AttendanceMachineUserRepository _machineUsers = new();
+    private readonly AttendanceMachineFaceTemplateRepository _faceTemplates = new();
+    private readonly HikvisionIsapiClient _hikvision = new();
+    private readonly TemplateSyncService _service;
+    private readonly ObservableCollection<SelectableMachineUser> _rows = [];
+    private CancellationTokenSource? _sourceStatusCts;
+    private CancellationTokenSource? _targetStatusCts;
+    private bool? _sourceConnected;
+    private bool? _targetConnected;
+    private bool _initialized;
+
+    public DeviceToDeviceView()
+    {
+        InitializeComponent();
+        _service = new TemplateSyncService(_hikvision, _machineUsers, _faceTemplates, new OperationHistoryService());
+        UsersGrid.ItemsSource = _rows;
+        UpdateUsersEmptyState();
+        UpdateSelectionCount();
+        UpdateActionState();
+    }
+
+    public async Task InitializeAsync()
+    {
+        if (_initialized) return;
+        _initialized = true;
+        await RefreshAsync();
+    }
+
+    public async Task RefreshAsync()
+    {
+        var originalContent = RefreshButton.Content;
+        try
+        {
+            RefreshButton.IsEnabled = false;
+            RefreshButton.Content = "Refreshing...";
+            _sourceStatusCts?.Cancel();
+            _targetStatusCts?.Cancel();
+            SourceCombo.SelectedItem = null;
+            TargetCombo.SelectedItem = null;
+            ClearUserList();
+            ProgressCard.Visibility = Visibility.Collapsed;
+            ProgressBar.Value = 0;
+            ProgressText.Text = "";
+            CounterText.Text = "";
+            LoadStatusText.Text = "";
+            SourceInfoBanner.Visibility = Visibility.Collapsed;
+            SameDeviceWarning.Visibility = Visibility.Collapsed;
+            TargetOfflineWarning.Visibility = Visibility.Collapsed;
+            _sourceConnected = null;
+            _targetConnected = null;
+            SetConnectionStatus(SourceStatusDot, SourceStatusText, null);
+            SetConnectionStatus(TargetStatusDot, TargetStatusText, null);
+            var devices = await _devices.LoadUnifiedAsync();
+            SourceCombo.ItemsSource = devices;
+            TargetCombo.ItemsSource = devices;
+        }
+        finally
+        {
+            RefreshButton.IsEnabled = true;
+            RefreshButton.Content = originalContent;
+        }
+    }
+
+    private async void Refresh_Click(object sender, RoutedEventArgs e) => await RefreshAsync();
+
+    private async void SourceChanged(object sender, SelectionChangedEventArgs e)
+    {
+        ClearUserList();
+        LoadStatusText.Text = "";
+        SourceInfoBanner.Visibility = Visibility.Collapsed;
+        await CheckSourceConnectionAsync();
+        UpdateSourceInfoBanner();
+        UpdateActionState();
+    }
+
+    private async void TargetChanged(object sender, SelectionChangedEventArgs e)
+    {
+        await CheckTargetConnectionAsync();
+        UpdateActionState();
+    }
+
+    private async Task CheckSourceConnectionAsync()
+    {
+        _sourceStatusCts?.Cancel();
+        _sourceStatusCts = new CancellationTokenSource();
+        var token = _sourceStatusCts.Token;
+
+        if (SourceCombo.SelectedItem is not Device device)
+        {
+            _sourceConnected = null;
+            SetConnectionStatus(SourceStatusDot, SourceStatusText, null);
+            return;
+        }
+
+        SetConnectionStatus(SourceStatusDot, SourceStatusText, null, "Checking connection...");
+        try
+        {
+            var result = await _connections.TestConnectivityAsync(device, token).ConfigureAwait(true);
+            if (token.IsCancellationRequested) return;
+            _sourceConnected = result.IsConnected;
+            SetConnectionStatus(SourceStatusDot, SourceStatusText, result.IsConnected,
+                result.IsConnected ? "Connected" : "Not Connected");
+        }
+        catch (OperationCanceledException)
+        {
+        }
+        catch (Exception ex)
+        {
+            if (token.IsCancellationRequested) return;
+            _sourceConnected = false;
+            SetConnectionStatus(SourceStatusDot, SourceStatusText, false, "Not Connected");
+            AppLogger.Warning($"Device→Device source connection check failed: {ex.Message}");
+        }
+    }
+
+    private async Task CheckTargetConnectionAsync()
+    {
+        _targetStatusCts?.Cancel();
+        _targetStatusCts = new CancellationTokenSource();
+        var token = _targetStatusCts.Token;
+
+        if (TargetCombo.SelectedItem is not Device device)
+        {
+            _targetConnected = null;
+            SetConnectionStatus(TargetStatusDot, TargetStatusText, null);
+            TargetOfflineWarning.Visibility = Visibility.Collapsed;
+            return;
+        }
+
+        SetConnectionStatus(TargetStatusDot, TargetStatusText, null, "Checking connection...");
+        try
+        {
+            var result = await _connections.TestConnectivityAsync(device, token).ConfigureAwait(true);
+            if (token.IsCancellationRequested) return;
+            _targetConnected = result.IsConnected;
+            SetConnectionStatus(TargetStatusDot, TargetStatusText, result.IsConnected,
+                result.IsConnected ? "Connected" : "Not Connected");
+            TargetOfflineWarning.Visibility = result.IsConnected ? Visibility.Collapsed : Visibility.Visible;
+        }
+        catch (OperationCanceledException)
+        {
+        }
+        catch (Exception ex)
+        {
+            if (token.IsCancellationRequested) return;
+            _targetConnected = false;
+            SetConnectionStatus(TargetStatusDot, TargetStatusText, false, "Not Connected");
+            TargetOfflineWarning.Visibility = Visibility.Visible;
+            AppLogger.Warning($"Device→Device target connection check failed: {ex.Message}");
+        }
+    }
+
+    private void UpdateSourceInfoBanner()
+    {
+        if (SourceCombo.SelectedItem is null || _sourceConnected is null)
+        {
+            SourceInfoBanner.Visibility = Visibility.Collapsed;
+            return;
+        }
+
+        SourceInfoBanner.Visibility = Visibility.Visible;
+        if (_sourceConnected == true)
+        {
+            SourceInfoBanner.Background = new SolidColorBrush(Color.FromRgb(236, 253, 245));
+            SourceInfoBanner.BorderBrush = new SolidColorBrush(Color.FromRgb(167, 243, 208));
+            SourceInfoText.Foreground = new SolidColorBrush(Color.FromRgb(4, 120, 87));
+            SourceInfoText.Text = "Source device connected. Users will be loaded directly from the device.";
+        }
+        else
+        {
+            SourceInfoBanner.Background = new SolidColorBrush(Color.FromRgb(255, 251, 235));
+            SourceInfoBanner.BorderBrush = new SolidColorBrush(Color.FromRgb(253, 230, 138));
+            SourceInfoText.Foreground = new SolidColorBrush(Color.FromRgb(180, 83, 9));
+            SourceInfoText.Text = "Source device is offline. Users will be loaded from the database for the selected source device.";
+        }
+    }
+
+    private async void LoadUsers_Click(object sender, RoutedEventArgs e)
+    {
+        if (SourceCombo.SelectedItem is not Device source)
+        {
+            MessageBox.Show("Select a source machine.", "Device → Device", MessageBoxButton.OK, MessageBoxImage.Information);
+            return;
+        }
+
+        if (_sourceConnected is null)
+            await CheckSourceConnectionAsync();
+
+        UpdateSourceInfoBanner();
+        _rows.Clear();
+        LoadStatusText.Text = "Loading users...";
+        LoadUsersButton.IsEnabled = false;
+
+        try
+        {
+            if (_sourceConnected == true)
+            {
+                var users = await _hikvision.GetUsersAsync(source, CancellationToken.None);
+                foreach (var user in users.OrderBy(u => u.EmployeeNo, StringComparer.OrdinalIgnoreCase))
+                    AddRow(user.EmployeeNo, user.Name, user.FaceCount > 0, "Device");
+
+                LoadStatusText.Text = $"Loaded {users.Count} user(s) from source Hikvision device.";
+            }
+            else
+            {
+                var users = await _machineUsers.GetActiveByMachineAsync(source.MachineId, CancellationToken.None);
+                foreach (var user in users.OrderBy(u => u.SerialNumber, StringComparer.OrdinalIgnoreCase))
+                {
+                    var template = await _faceTemplates.TryGetActiveAsync(user.SerialNumber, CancellationToken.None);
+                    var hasFace = template?.Template is { Length: > 0 } &&
+                                  HikvisionIsapiClient.IsUploadableFaceTemplate(template.Template);
+                    AddRow(user.SerialNumber, user.EmployeeName, hasFace, "DB");
+                }
+
+                LoadStatusText.Text = $"Source device offline — loaded {users.Count} user(s) from DB.";
+            }
+        }
+        catch (Exception ex)
+        {
+            LoadStatusText.Text = "Unable to load users: " + ex.Message;
+            MessageBox.Show(ex.Message, "Device → Device", MessageBoxButton.OK, MessageBoxImage.Error);
+        }
+        finally
+        {
+            LoadUsersButton.IsEnabled = true;
+            UpdateUsersEmptyState();
+            UpdateSelectionCount();
+        }
+    }
+
+    private void AddRow(string serialNumber, string employeeName, bool hasFace, string sourceDisplay)
+    {
+        var row = new SelectableMachineUser(serialNumber, employeeName, hasFace, sourceDisplay);
+        row.PropertyChanged += RowSelectionChanged;
+        _rows.Add(row);
+    }
+
+    private void RowSelectionChanged(object? sender, PropertyChangedEventArgs e)
+    {
+        if (e.PropertyName == nameof(SelectableMachineUser.IsSelected))
+        {
+            UpdateSelectionCount();
+            UpdateActionState();
+        }
+    }
+
+    private void ClearUserList()
+    {
+        foreach (var row in _rows)
+            row.PropertyChanged -= RowSelectionChanged;
+        _rows.Clear();
+        UpdateUsersEmptyState();
+        UpdateSelectionCount();
+    }
+
+    private void SelectAll_Click(object sender, RoutedEventArgs e)
+    {
+        foreach (var row in _rows) row.IsSelected = true;
+        UsersGrid.Items.Refresh();
+        UpdateSelectionCount();
+        UpdateActionState();
+    }
+
+    private void ClearSelection_Click(object sender, RoutedEventArgs e)
+    {
+        foreach (var row in _rows) row.IsSelected = false;
+        UsersGrid.Items.Refresh();
+        UpdateSelectionCount();
+        UpdateActionState();
+    }
+
+    private void UpdateUsersEmptyState()
+    {
+        UsersEmptyState.Visibility = _rows.Count == 0 ? Visibility.Visible : Visibility.Collapsed;
+    }
+
+    private void UpdateSelectionCount()
+    {
+        var selected = _rows.Count(r => r.IsSelected);
+        SelectionCountText.Text = $"{_rows.Count} user(s) loaded • {selected} selected";
+    }
+
+    private bool IsSameDeviceSelected()
+    {
+        if (SourceCombo.SelectedItem is not Device source || TargetCombo.SelectedItem is not Device target)
+            return false;
+
+        return string.Equals(source.MachineId, target.MachineId, StringComparison.OrdinalIgnoreCase) &&
+               string.Equals(source.IpAddress, target.IpAddress, StringComparison.OrdinalIgnoreCase);
+    }
+
+    private void UpdateActionState()
+    {
+        var sameDevice = IsSameDeviceSelected();
+        SameDeviceWarning.Visibility = sameDevice ? Visibility.Visible : Visibility.Collapsed;
+
+        var canTransfer = !sameDevice &&
+                          _targetConnected == true &&
+                          _rows.Any(r => r.IsSelected) &&
+                          SourceCombo.SelectedItem is Device &&
+                          TargetCombo.SelectedItem is Device;
+
+        TransferButton.IsEnabled = canTransfer;
+    }
+
+    private async void Transfer_Click(object sender, RoutedEventArgs e)
+    {
+        if (SourceCombo.SelectedItem is not Device source || TargetCombo.SelectedItem is not Device target)
+        {
+            MessageBox.Show("Select source and target machines.", "Device → Device", MessageBoxButton.OK, MessageBoxImage.Information);
+            return;
+        }
+
+        if (IsSameDeviceSelected())
+        {
+            MessageBox.Show("Source and target devices must be different.", "Device → Device", MessageBoxButton.OK, MessageBoxImage.Warning);
+            return;
+        }
+
+        if (_targetConnected is null)
+            await CheckTargetConnectionAsync();
+
+        if (_targetConnected != true)
+        {
+            MessageBox.Show("Target device is not connected. Connect the target device before transferring users.",
+                "Device → Device", MessageBoxButton.OK, MessageBoxImage.Warning);
+            return;
+        }
+
+        if (_sourceConnected is null)
+            await CheckSourceConnectionAsync();
+
+        var selected = _rows.Where(r => r.IsSelected)
+            .Select(r => new DeviceTransferUser(r.SerialNumber, r.EmployeeName))
+            .ToList();
+        if (selected.Count == 0)
+        {
+            MessageBox.Show("Select at least one user.", "Device → Device", MessageBoxButton.OK, MessageBoxImage.Information);
+            return;
+        }
+
+        ProgressCard.Visibility = Visibility.Visible;
+        TransferButton.IsEnabled = false;
+        var progress = new Progress<UserSyncProgress>(p =>
+        {
+            ProgressBar.Maximum = Math.Max(1, p.Total);
+            ProgressBar.Value = p.Completed;
+            ProgressText.Text = $"{p.Completed}/{p.Total} · {p.CurrentEmployee} · {p.CurrentOperation}";
+            CounterText.Text = $"Users: {p.Created} · Faces: {p.FacesUploaded} · Skipped: {p.Skipped} · Failed: {p.Failed}";
+        });
+
+        try
+        {
+            var entry = await _service.DeviceToDeviceAsync(source, target, selected, _sourceConnected == true, progress, CancellationToken.None);
+            ProgressText.Text = $"Completed — {entry.Status}";
+            CounterText.Text = entry.Context;
+        }
+        catch (Exception ex)
+        {
+            MessageBox.Show(ex.Message, "Device → Device", MessageBoxButton.OK, MessageBoxImage.Error);
+        }
+        finally
+        {
+            UpdateActionState();
+        }
+    }
+
+    private static void SetConnectionStatus(System.Windows.Shapes.Ellipse dot, TextBlock label, bool? connected, string? text = null)
+    {
+        if (connected is null)
+        {
+            dot.Fill = new SolidColorBrush(Color.FromRgb(156, 163, 175));
+            label.Text = text ?? "Select a device";
+            label.Foreground = new SolidColorBrush(Color.FromRgb(100, 116, 139));
+            return;
+        }
+
+        if (connected == true)
+        {
+            dot.Fill = new SolidColorBrush(Color.FromRgb(22, 163, 74));
+            label.Text = text ?? "Connected";
+            label.Foreground = new SolidColorBrush(Color.FromRgb(22, 163, 74));
+        }
+        else
+        {
+            dot.Fill = new SolidColorBrush(Color.FromRgb(220, 38, 38));
+            label.Text = text ?? "Not Connected";
+            label.Foreground = new SolidColorBrush(Color.FromRgb(220, 38, 38));
+        }
+    }
+}