diff --git a/ps_simulator.rb b/ps_simulator.rb
index 11b102b..a2cc4d8 100755
--- a/ps_simulator.rb
+++ b/ps_simulator.rb
@@ -4,6 +4,9 @@
 require 'serialport'
 require './telegram'
 
+# print debug info
+DEBUG = true
+# connect to PC
 pc_serial = SerialPort.open("/dev/ttyUSB0",{ baud: 57600, databits: 8, parity: SerialPort::ODD, stop_bit: 1, flow_control: SerialPort::NONE})
 
 # ensure serial settings (weird bug)
@@ -16,14 +19,31 @@ while true
     data = activity.readpartial(16+1+5)
     line = data.unpack("C*").collect { |b| sprintf("%02X ",b) }.join
     if activity==pc_serial then
-      puts "> "+line
+      puts "> "+line if DEBUG
       begin
-        telegram = Telegram.parse(data)
-        if telegram then
-          puts "> "+telegram.to_s[2..-1]
+        telegram_in = Telegram.parse(data)
+        if telegram_in then
+          puts "> "+telegram_in.to_s[2..-1]
         else
 		  raise "could not parse message"
 		end
+        telegram_out = case telegram_in.object
+          when 0 # device type
+			# Telegram.new(telegram_in.object,[0x50,0x53,0x20,0x32,0x30,0x38,0x34,0x2D,0x30,0x33,0x42,0x00])
+            Telegram.new(telegram_in.object,"simulator".bytes.to_a+[0x00],false)
+          when 1, 6, 9 # article no., serial no., software version
+            Telegram.new(telegram_in.object,"42".bytes.to_a+[0x00],false)
+          when 2,3,4 # nominal voltage, current, power
+            Telegram.new(telegram_in.object,[42.0].pack("g").bytes.to_a,false)
+          when 19 # device class
+            Telegram.new(telegram_in.object,[0x00,0x10],false)
+          else # error: object not defined
+            Telegram.new(0xff,[0x07],false)
+        end
+        if telegram_out then
+          puts "< "+telegram_out.to_s[2..-1] # display message
+          pc_serial.write(telegram_out.pack) # send message
+        end
       rescue Exception => e
         puts e.to_s
       end