diff --git a/SmvViewerWindow.xaml.cs b/SmvViewerWindow.xaml.cs
index 5778b613b..6113a54f8 100644
--- a/SmvViewerWindow.xaml.cs
+++ b/SmvViewerWindow.xaml.cs
@@ -32,7 +32,7 @@ public partial class SmvViewerWindow : Window, INotifyPropertyChanged
     private CancellationTokenSource? _captureCancellation;
     private SmvSnapshotResult? _snapshot;
     private string _statusText = string.Empty;
-    private string _captureStatusText = "Select an adapter and stream, then capture a bounded two-cycle snapshot.";
+    private string _captureStatusText = "Select an Ethernet adapter, then capture the first received SV stream or select a configured stream.";
     private string _snapshotBadgeText = "No snapshot";
     private string _snapshotSummaryText = "No Sampled Values snapshot has been captured yet.";
     private string _snapshotEvidenceText = "The snapshot will report stream identity, payload shape, sample-counter continuity and a static raw waveform.";
@@ -52,10 +52,11 @@ public SmvViewerWindow(Iec61850MonitorDevice device)
         foreach (var row in BuildRows(device))
             Streams.Add(row);
 
-        SelectedStream = Streams.FirstOrDefault();
-        StatusText = Streams.Count == 0
-            ? "No Sampled Value control block is configured in the opened SCL model or discovered from this IED."
-            : $"{Streams.Count:N0} Sampled Value stream definition(s) are available. Snapshot capture is passive and does not write to the IED.";
+        SelectedStream = Streams[0];
+        var configured = Streams.Count - 1;
+        StatusText = configured == 0
+            ? "Ready for passive SV capture on Ethernet. Select the correct Npcap adapter and Capture to discover the first stream."
+            : $"Capture any received SV stream or choose one of {configured:N0} configured stream(s). No network frame is transmitted.";
         DataContext = this;
     }
 
@@ -127,9 +128,11 @@ public SmvStreamRow? SelectedStream
     }
 
     public string SelectedStreamDetail => SelectedStream == null
-        ? "Select one stream before starting the bounded capture."
-        : $"{SelectedStream.Source} • {SelectedStream.ControlReference} • DataSet {SelectedStream.DataSetReference} • " +
-          $"APPID {SelectedStream.AppId} • {SelectedStream.MemberCount} member(s).";
+        ? "Select an SV stream or the auto-discovery option."
+        : SelectedStream.Source == "Live Ethernet (auto)"
+            ? "Automatically capture the first decodable SV stream arriving on the selected Ethernet adapter. No SCL, APPID, MAC or svID filter is required."
+            : $"{SelectedStream.Source} • {SelectedStream.ControlReference} • DataSet {SelectedStream.DataSetReference} • " +
+              $"APPID {SelectedStream.AppId} • {SelectedStream.MemberCount} member(s).";
 
     private void Window_Loaded(object sender, RoutedEventArgs e)
     {
@@ -556,6 +559,25 @@ private void Raise([CallerMemberName] string? propertyName = null)
 
 public sealed class SmvStreamRow
 {
+    /// <summary>
+    /// Passive first-stream discovery. The capture request normalizes "-"
+    /// into unrestricted APPID, MAC, svID and timebase hints.
+    /// </summary>
+    public static SmvStreamRow AnyReceived() => new()
+    {
+        Source = "Live Ethernet (auto)",
+        ControlReference = "First received SV stream",
+        StreamId = "-",
+        DataSetReference = "-",
+        AppId = "-",
+        DestinationMac = "-",
+        Vlan = "-",
+        SampleRate = "-",
+        SampleMode = "-",
+        NumberOfAsdu = "-",
+        MemberCount = 0
+    };
+
     public string Source { get; init; } = string.Empty;
     public string LiveKey { get; init; } = string.Empty;
     public string ControlReference { get; init; } = string.Empty;
diff --git a/tests/ARSAS.Tests/ArstackM3hSvInteropTests.cs b/tests/ARSAS.Tests/ArstackM3hSvInteropTests.cs
new file mode 100644
index 000000000..48893dc9f
--- /dev/null
+++ b/tests/ARSAS.Tests/ArstackM3hSvInteropTests.cs
@@ -0,0 +1,80 @@
+using System.Buffers.Binary;
+using System.Text;
+using AR.Iec61850.SampledValues;
+using Xunit;
+
+namespace ARSAS.Tests;
+
+/// <summary>
+/// Checks that ARSAS's pinned native SV parser accepts the ARStack M3.H
+/// reference layout, including priority-tagged VLAN ID 0.
+/// This is a wire-decoder test, not evidence of physical Ethernet delivery.
+/// </summary>
+public sealed class ArstackM3hSvInteropTests
+{
+    [Theory]
+    [InlineData(true)]
+    [InlineData(false)]
+    public void SnapshotEngine_RecognizesM3h4I4VFrame(bool vlanPriorityTag)
+    {
+        var sampleData = new byte[64];
+        var analogValues = new[] { 2500, -1250, -1250, 0, 330000, -165000, -165000, 0 };
+        for (var i = 0; i < analogValues.Length; i++)
+            BinaryPrimitives.WriteInt32BigEndian(sampleData.AsSpan(i * 8, 4), analogValues[i]);
+
+        var asdu = Tlv(0x30,
+            Tlv(0x80, Encoding.ASCII.GetBytes("MU01_SV1")),
+            Tlv(0x82, U16(3999)),
+            Tlv(0x83, new byte[] { 0x00, 0x00, 0x00, 0x01 }),
+            Tlv(0x85, new byte[] { 0x02 }),
+            Tlv(0x87, sampleData),
+            Tlv(0x89, new byte[] { 0x02, 0x11, 0x22, 0xFF, 0xFE, 0x33, 0x44, 0x55 }));
+
+        var apdu = Tlv(0x60,
+            Tlv(0x80, new byte[] { 0x01 }),
+            Tlv(0xA2, asdu));
+        var payload = Join(U16(0x4000), U16((ushort)(8 + apdu.Length)),
+            U16(0), U16(0), apdu);
+        var ethernet = vlanPriorityTag
+            ? Join(DestinationMac, SourceMac, U16(0x8100), U16(0x8000), U16(0x88BA), payload)
+            : Join(DestinationMac, SourceMac, U16(0x88BA), payload);
+
+        Assert.True(SampledValuesFrameParser.TryParseEthernetFrame(ethernet, out var frame));
+        Assert.Equal((ushort)0x4000, frame.AppId);
+        Assert.Equal(vlanPriorityTag, frame.Vlan is not null);
+        if (vlanPriorityTag)
+            Assert.Equal((ushort)0, frame.Vlan?.VlanId);
+        var decoded = Assert.Single(frame.Pdu.Asdus);
+        Assert.Equal("MU01_SV1", decoded.SvId);
+        Assert.Equal((ushort)3999, decoded.SampleCount);
+        Assert.Equal(64, decoded.SamplePayload.Length);
+    }
+
+    private static readonly byte[] DestinationMac = { 0x01, 0x0C, 0xCD, 0x04, 0x00, 0x01 };
+    private static readonly byte[] SourceMac = { 0x02, 0x11, 0x22, 0x33, 0x44, 0x55 };
+
+    private static byte[] U16(ushort number) => new[] { (byte)(number >> 8), (byte)number };
+
+    private static byte[] Tlv(byte tag, params byte[][] parts)
+    {
+        var content = Join(parts);
+        if (content.Length < 128)
+            return Join(new byte[] { tag, (byte)content.Length }, content);
+        if (content.Length < 256)
+            return Join(new byte[] { tag, 0x81, (byte)content.Length }, content);
+        return Join(new byte[] { tag, 0x82, (byte)(content.Length >> 8), (byte)content.Length }, content);
+    }
+
+    private static byte[] Join(params byte[][] arrays)
+    {
+        var size = arrays.Sum(a => a.Length);
+        var result = new byte[size];
+        var index = 0;
+        foreach (var array in arrays)
+        {
+            array.CopyTo(result, index);
+            index += array.Length;
+        }
+        return result;
+    }
+}
diff --git a/tests/ARSAS.Tests/SmvFirstReceivedStreamTests.cs b/tests/ARSAS.Tests/SmvFirstReceivedStreamTests.cs
new file mode 100644
index 000000000..2afa619f4
--- /dev/null
+++ b/tests/ARSAS.Tests/SmvFirstReceivedStreamTests.cs
@@ -0,0 +1,20 @@
+using ArIED61850Tester;
+
+namespace ARSAS.Tests;
+
+public sealed class SmvFirstReceivedStreamTests
+{
+    [Fact]
+    public void NewOperatorCanReceiveAnySvWithoutMatchingSclIdentity()
+    {
+        var row = SmvStreamRow.AnyReceived();
+
+        Assert.Equal("Live Ethernet (auto)", row.Source);
+        Assert.Equal("-", row.AppId);
+        Assert.Equal("-", row.StreamId);
+        Assert.Equal("-", row.DestinationMac);
+        Assert.Equal("-", row.SampleRate);
+        Assert.Equal("-", row.SampleMode);
+        Assert.Equal(0, row.MemberCount);
+    }
+}