2 files changed, 15 insertions, 4 deletions
diff --git a/src/main/java/org/traccar/protocol/AstraProtocolDecoder.java b/src/main/java/org/traccar/protocol/AstraProtocolDecoder.java
index 366bf9e8b..a7bfd4625 100644
--- a/src/main/java/org/traccar/protocol/AstraProtocolDecoder.java
+++ b/src/main/java/org/traccar/protocol/AstraProtocolDecoder.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2016 - 2018 Anton Tananaev (anton@traccar.org)
+ * Copyright 2016 - 2024 Anton Tananaev (anton@traccar.org)
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -51,13 +51,21 @@ public class AstraProtocolDecoder extends BaseProtocolDecoder {
 
         ByteBuf buf = (ByteBuf) msg;
 
+        byte protocol = buf.readByte();
+        buf.readUnsignedShort(); // length
+
+        return switch (protocol) {
+            case 'K' -> decodeK(channel, remoteAddress, buf);
+            default -> null;
+        };
+    }
+
+    private Object decodeK(Channel channel, SocketAddress remoteAddress, ByteBuf buf) {
+
         if (channel != null) {
             channel.writeAndFlush(new NetworkMessage(Unpooled.wrappedBuffer(new byte[] {0x06}), remoteAddress));
         }
 
-        buf.readUnsignedByte(); // protocol
-        buf.readUnsignedShort(); // length
-
         String imei = String.format("%08d", buf.readUnsignedInt()) + String.format("%07d", buf.readUnsignedMedium());
         DeviceSession deviceSession = getDeviceSession(channel, remoteAddress, imei);
         if (deviceSession == null) {
diff --git a/src/test/java/org/traccar/protocol/AstraProtocolDecoderTest.java b/src/test/java/org/traccar/protocol/AstraProtocolDecoderTest.java
index 3dabcac5d..cf1978f4e 100644
--- a/src/test/java/org/traccar/protocol/AstraProtocolDecoderTest.java
+++ b/src/test/java/org/traccar/protocol/AstraProtocolDecoderTest.java
@@ -10,6 +10,9 @@ public class AstraProtocolDecoderTest extends ProtocolTest {
 
         var decoder = inject(new AstraProtocolDecoder(null));
 
+        verifyNull(decoder, binary(
+                "58003d018b0000000000bf514f00b70000006000093e60514f00b6032fec49ffdc7627000041020000000100010000000000090001010000008f00aba3"));
+
         verifyPositions(decoder, binary(
                 "4b00700529c0c265976b8202cba9ff00676d864554a9c30000000020073401006436000300030008000000000000a0000100001920c43d00009600428302cba9ff00676d864554aa3e000000002007240100643b000300020008000000000000b0000100001920c43d00009600420f0e"));