diff --git a/pom.xml b/pom.xml
index 24ca168..7d88195 100644
--- a/pom.xml
+++ b/pom.xml
@@ -4,7 +4,7 @@
 	<modelVersion>4.0.0</modelVersion>
 	<groupId>de.srsoftware</groupId>
 	<artifactId>web4rail</artifactId>
-	<version>0.5.0</version>
+	<version>0.5.1</version>
 	<name>Web4Rail</name>
 	<description>Java Model Railway Control</description>
 	<url>https://github.com/StephanRichter/Web4Rail</url>
diff --git a/src/main/java/de/srsoftware/web4rail/ControlUnit.java b/src/main/java/de/srsoftware/web4rail/ControlUnit.java
index face799..c02ca6d 100644
--- a/src/main/java/de/srsoftware/web4rail/ControlUnit.java
+++ b/src/main/java/de/srsoftware/web4rail/ControlUnit.java
@@ -4,16 +4,47 @@ import java.io.IOException;
 import java.net.Socket;
 import java.nio.charset.StandardCharsets;
 import java.util.LinkedList;
+import java.util.Scanner;
 
-public class ControlUnit extends Thread{
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class ControlUnit extends Thread{	
+	private static final Logger LOG = LoggerFactory.getLogger(ControlUnit.class);
 	private static final String DEFAULT_HOST = "localhost";
 	private static final int DEFAULT_PORT = 4303;
+	private static final int OK_PROTO = 201;
+	private static final int OK_MODE = 202;
+	
+	private class Reply{
+		private long secs;
+		private int milis;
+		private int code;
+		private String message;
+		
+		public Reply(Scanner scanner) {
+			String word = scanner.next();
+			secs = Long.parseLong(word.substring(0, word.length()-4));
+			milis = Integer.parseInt(word.substring(word.length()-3));
+			code = scanner.nextInt();
+			message = scanner.nextLine().trim();
+			LOG.debug("recv {}.{} {} {}.",secs,milis,code,message);
+		}
+
+		@Override
+		public String toString() {
+			return "Reply("+secs+"."+milis+" / "+code+" / "+message+")";
+		}
+	}
+	
+	
 	
 	private String host = DEFAULT_HOST;
 	private int port = DEFAULT_PORT;
 	private boolean stopped = true;
 	private LinkedList<String> queue = new LinkedList<String>();
 	private Socket socket;
+	private Scanner scanner;
 
 	/**
 	 * @return stops the loop at the next interval
@@ -24,8 +55,12 @@ public class ControlUnit extends Thread{
 	}
 
 	
-	public static void main(String[] args) {
-		new ControlUnit().setEndpoint("127.0.0.1", DEFAULT_PORT).restart();
+	public static void main(String[] args) throws InterruptedException {
+		ControlUnit cu = new ControlUnit().setEndpoint("Modellbahn", DEFAULT_PORT).restart();
+		Thread.sleep(1000);
+		cu.queue("SET 0 GL 1 0 10");
+		Thread.sleep(1000);
+		cu.end();
 	}
 	
 	public void queue(String command) {
@@ -67,7 +102,8 @@ public class ControlUnit extends Thread{
 	 */
 	private void send(String command) throws IOException {
 		if (command == null) return;
-		socket.getOutputStream().write(command.getBytes(StandardCharsets.UTF_8));
+		writeln(command);
+		Reply reply = new Reply(scanner);
 	}
 	
 	public ControlUnit setEndpoint(String newHost, int newPort){
@@ -80,9 +116,40 @@ public class ControlUnit extends Thread{
 	public synchronized void start() {
 		try {
 			socket = new Socket(host, port);
+			scanner = new Scanner(socket.getInputStream());
+			handshake();			
+			stopped = false;
 		} catch (IOException e) {
 			throw new IllegalStateException(e);
 		}
 		super.start();
 	}
+
+
+	private void handshake() throws IOException {
+		String proto = null;
+		if (scanner.hasNext()) {
+			String line = scanner.nextLine();
+			LOG.debug("recv: "+line);
+			for (String part : line.split(";")) {
+				part = part.trim();
+				if (part.startsWith("SRCP ")) proto = part.substring(5); 
+			}
+			if (proto == null) throw new IOException("Handshake failed: "+line);
+			if (!proto.startsWith("0.8.")) throw new IOException("Unsupported protocol: "+proto);
+			writeln("SET PROTOCOL SRCP "+proto);			
+		} else throw new IOException("Handshake expected.");
+		
+		Reply reply = new Reply(scanner);
+		if (reply.code != OK_PROTO) throw new IOException("Handshake failed: "+reply);
+		
+		writeln("SET CONNECTIONMODE SRCP COMMAND");
+		reply = new Reply(scanner);
+		if (reply.code != OK_MODE) throw new IOException("Handshake failed: "+reply);
+	}
+
+	private void writeln(String data) throws IOException {
+		socket.getOutputStream().write((data+"\n").getBytes(StandardCharsets.US_ASCII));
+		LOG.debug("sent {}.",data);
+	}
 }