diff --git a/src/main/java/org/traccar/helper/BufferUtil.java b/src/main/java/org/traccar/helper/BufferUtil.java
index b453c437f..94d7f5fde 100644
--- a/src/main/java/org/traccar/helper/BufferUtil.java
+++ b/src/main/java/org/traccar/helper/BufferUtil.java
@@ -87,4 +87,13 @@ public final class BufferUtil {
         return buf.readCharSequence(length, StandardCharsets.US_ASCII).toString();
     }
 
+    public static String readDecimalDigits(ByteBuf buf, int byteCount) {
+        StringBuilder builder = new StringBuilder(byteCount * 2);
+        for (int i = 0; i < byteCount; i++) {
+            int b = buf.readUnsignedByte();
+            builder.append(b / 10).append(b % 10);
+        }
+        return builder.toString();
+    }
+
 }
diff --git a/src/main/java/org/traccar/protocol/M2mProtocolDecoder.java b/src/main/java/org/traccar/protocol/M2mProtocolDecoder.java
index 7eca93a59..1968c91aa 100644
--- a/src/main/java/org/traccar/protocol/M2mProtocolDecoder.java
+++ b/src/main/java/org/traccar/protocol/M2mProtocolDecoder.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2013 - 2018 Anton Tananaev (anton@traccar.org)
+ * Copyright 2013 - 2026 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.
@@ -20,6 +20,7 @@ import io.netty.channel.Channel;
 import org.traccar.BaseProtocolDecoder;
 import org.traccar.session.DeviceSession;
 import org.traccar.Protocol;
+import org.traccar.helper.BufferUtil;
 import org.traccar.helper.DateBuilder;
 import org.traccar.model.Position;
 
@@ -51,16 +52,9 @@ public class M2mProtocolDecoder extends BaseProtocolDecoder {
 
             firstPacket = false;
 
-            StringBuilder imei = new StringBuilder();
-            for (int i = 0; i < 8; i++) {
-                int b = buf.readByte();
-                if (i != 0) {
-                    imei.append(b / 10);
-                }
-                imei.append(b % 10);
-            }
+            String imei = BufferUtil.readDecimalDigits(buf, 8).substring(1);
 
-            getDeviceSession(channel, remoteAddress, imei.toString());
+            getDeviceSession(channel, remoteAddress, imei);
 
         } else {
 
diff --git a/src/test/java/org/traccar/helper/BufferUtilTest.java b/src/test/java/org/traccar/helper/BufferUtilTest.java
index 707e419ec..d893c1cb2 100644
--- a/src/test/java/org/traccar/helper/BufferUtilTest.java
+++ b/src/test/java/org/traccar/helper/BufferUtilTest.java
@@ -38,4 +38,10 @@ public class BufferUtilTest {
         assertEquals(3, BufferUtil.indexOf("de", buf, 2, 6));
     }
 
+    @Test
+    public void testReadDecimalDigits() {
+        ByteBuf buf = Unpooled.wrappedBuffer(DataConverter.parseHex("0b1621"));
+        assertEquals("112233", BufferUtil.readDecimalDigits(buf, 3));
+    }
+
 }