diff --git a/apps/call_timer/CallTimer.cpp b/apps/call_timer/CallTimer.cpp
new file mode 100644
index 00000000..3087a5be
--- /dev/null
+++ b/apps/call_timer/CallTimer.cpp
@@ -0,0 +1,269 @@
+/*
+ * $Id: $
+ *
+ * Copyright (C) 2008 iptego GmbH
+ * Based on the concept of auth_b2b, Copyright (C) 2008 iptego GmbH
+ * Based on the concept of mycc, Copyright (C) 2007 Sipwise GmbH
+ * Based on the concept of sw_prepaid_sip, Copyright (C) 2002-2003 Fhg Fokus
+ *
+ * This file is part of sems, a free SIP media server.
+ *
+ * sems is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * For a license to use the sems software under conditions
+ * other than those described here, or to purchase support for this
+ * software, please contact iptel.org by e-mail at the following addresses:
+ *    info@iptel.org
+ *
+ * sems is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include "CallTimer.h"
+
+#include "log.h"
+#include "AmUtils.h"
+#include "AmAudio.h"
+#include "AmPlugIn.h"
+#include "AmMediaProcessor.h"
+#include "AmConfigReader.h"
+#include "AmSessionContainer.h"
+
+#define TIMERID_CALL_TIMER 1
+
+#define DEFAULT_CALL_TIMER 1200  // 2 h default call timer
+
+unsigned int CallTimerFactory::DefaultCallTimer; 
+bool         CallTimerFactory::UseAppParam = true;
+
+EXPORT_SESSION_FACTORY(CallTimerFactory,MOD_NAME);
+
+CallTimerFactory::CallTimerFactory(const string& _app_name)
+: AmSessionFactory(_app_name), 
+  user_timer_fact(NULL)
+{
+}
+
+CallTimerFactory::~CallTimerFactory() {
+}
+
+
+
+int CallTimerFactory::onLoad()
+{
+  AmConfigReader cfg;
+  if(cfg.loadFile(AmConfig::ModConfigPath + string(MOD_NAME ".conf"))) {
+    DBG("using default timer of %d seconds\n", DEFAULT_CALL_TIMER);
+    DefaultCallTimer = DEFAULT_CALL_TIMER;
+  } else {
+    DefaultCallTimer  = cfg.getParameterInt("default_call_time", DEFAULT_CALL_TIMER);
+    UseAppParam = (cfg.getParameter("use_app_param") == "yes");
+  }
+
+  user_timer_fact = AmPlugIn::instance()->getFactory4Di("user_timer");
+  if(!user_timer_fact) {
+    ERROR("could not load user_timer from session_timer plug-in\n");
+    return -1;
+  }
+
+  return 0;
+}
+
+
+AmSession* CallTimerFactory::onInvite(const AmSipRequest& req)
+{
+  DBG(" *** creating new call timer session ***\n");
+  AmDynInvoke* user_timer = user_timer_fact->getInstance();
+  if(!user_timer) {
+    ERROR("could not get a user timer reference\n");
+     throw AmSession::Exception(500,"could not get a user timer reference");
+  }
+
+  string app_param = getHeader(req.hdrs, PARAM_HDR);
+
+  unsigned int call_time = CallTimerFactory::DefaultCallTimer;
+
+  if (CallTimerFactory::UseAppParam) {
+    if (!app_param.length()) {
+      INFO("call_time: no call timer parameters found. "
+	   "Using default value of %d seconds\n", 
+	   CallTimerFactory::DefaultCallTimer);
+    } else {
+      string call_time_s = get_header_keyvalue(app_param,"t", "Timer");
+      
+      if (str2i(call_time_s, call_time)) {
+	WARN("Error decoding call time value '%s'. Using default time of %d\n",
+	     call_time_s.c_str(), call_time);
+      } 
+    }
+  }
+
+  DBG("using call timer %d seconds\n", call_time);
+
+  return new CallTimerDialog(user_timer, call_time);
+}
+
+
+CallTimerDialog::CallTimerDialog(AmDynInvoke* user_timer,
+				 unsigned int call_time)
+: m_state(BB_Init),
+  call_time(call_time),
+  m_user_timer(user_timer),
+  AmB2BCallerSession()
+
+{
+  set_sip_relay_only(false);
+}
+
+
+CallTimerDialog::~CallTimerDialog()
+{
+}
+
+void CallTimerDialog::onInvite(const AmSipRequest& req)
+{
+
+  if (dlg.getStatus() == AmSipDialog::Connected) {
+    DBG("not acting on re-Invite\n");
+    return;
+  }
+    
+  setReceiving(false);
+  AmMediaProcessor::instance()->removeSession(this);
+
+  m_state = BB_Dialing;
+
+  if(dlg.reply(req, 100, "Trying") != 0) {
+    throw AmSession::Exception(500,"Failed to reply 100");
+  }
+
+  invite_req = req;
+  size_t pos1, pos2, hdr_start;
+
+  // remove P-App-Name, P-App-Param header
+  if (findHeader(invite_req.hdrs,PARAM_HDR, pos1, pos2, 
+		 hdr_start)) {
+    while (invite_req.hdrs[pos2]=='\r' ||invite_req.hdrs[pos2]=='\n') 
+      pos2++;
+
+    hdr_start -= 11; //"P-App-Param"
+    invite_req.hdrs.erase(hdr_start, pos2-hdr_start);
+  }
+
+  if (findHeader(invite_req.hdrs,"P-App-Name", pos1, pos2, 
+		 hdr_start)) {
+    while (invite_req.hdrs[pos2]=='\r' ||invite_req.hdrs[pos2]=='\n') 
+      pos2++;
+    hdr_start -= 10; //"P-App-Name"
+    invite_req.hdrs.erase(hdr_start, pos2-hdr_start);
+  }
+
+  dlg.updateStatus(invite_req);
+  recvd_req.insert(std::make_pair(invite_req.cseq,invite_req));
+  
+  set_sip_relay_only(true);
+  connectCallee(invite_req.to, invite_req.r_uri, true);
+}
+
+void CallTimerDialog::process(AmEvent* ev)
+{
+  AmPluginEvent* plugin_event = dynamic_cast<AmPluginEvent*>(ev);
+  if(plugin_event && plugin_event->name == "timer_timeout") {
+    int timer_id = plugin_event->data.get(0).asInt();
+    if (timer_id == TIMERID_CALL_TIMER) {
+      DBG("timer timeout.\n");
+      terminateOtherLeg();
+      dlg.bye();
+      terminateLeg();
+      ev->processed = true;
+      return;
+    }
+  }
+  
+  AmB2BCallerSession::process(ev);
+}
+
+
+bool CallTimerDialog::onOtherReply(const AmSipReply& reply)
+{
+  bool ret = false;
+
+  if (m_state == BB_Dialing) {
+    if (reply.code < 200) {
+      DBG("Callee is trying... code %d\n", reply.code);
+    }
+    else if(reply.code < 300) {
+      if(getCalleeStatus()  == Connected) {
+        m_state = BB_Connected;
+        setInOut(NULL, NULL);
+	// startAccounting();
+	// set the call timer
+	AmArg di_args,ret;
+	di_args.push(TIMERID_CALL_TIMER);
+	di_args.push((int)call_time);  // in seconds
+	di_args.push(dlg.local_tag.c_str());
+        m_user_timer->invoke("setTimer", di_args, ret);
+      }
+    }
+    else if(reply.code == 487 && dlg.getStatus() == AmSipDialog::Pending) {
+      DBG("Stopping leg A on 487 from B with 487\n");
+      dlg.reply(invite_req, 487, "Request terminated");
+      setStopped();
+      ret = true;
+    }
+    else if (reply.code >= 300 && dlg.getStatus() == AmSipDialog::Connected) {
+      DBG("Callee final error in connected state with code %d\n",reply.code);
+      terminateLeg();
+    }
+    else if (reply.code >= 300 && m_state == BB_Dialing) {
+      DBG("Callee final error with code %d\n",reply.code);
+      AmB2BCallerSession::onOtherReply(reply);
+      // reset into non-b2b mode to get possible INVITE again
+      sip_relay_only = false;
+    } else {
+      DBG("Callee final error with code %d\n",reply.code);
+      AmB2BCallerSession::onOtherReply(reply);
+    }
+  }
+  return ret;
+}
+
+
+void CallTimerDialog::onOtherBye(const AmSipRequest& req)
+{
+//   stopAccounting();
+  AmB2BCallerSession::onOtherBye(req);
+}
+
+
+void CallTimerDialog::onBye(const AmSipRequest& req)
+{
+  if (m_state == BB_Connected) {
+//     stopAccounting();
+  }
+  terminateOtherLeg();
+  setStopped();
+}
+
+
+void CallTimerDialog::onCancel()
+{
+  if(dlg.getStatus() == AmSipDialog::Pending) {
+    DBG("Wait for leg B to terminate");
+  }
+  else {
+    DBG("Canceling leg A on CANCEL since dialog is not pending");
+    dlg.reply(invite_req, 487, "Request terminated");
+    setStopped();
+  }
+}
+
diff --git a/apps/call_timer/CallTimer.h b/apps/call_timer/CallTimer.h
new file mode 100644
index 00000000..358afdd8
--- /dev/null
+++ b/apps/call_timer/CallTimer.h
@@ -0,0 +1,85 @@
+/*
+ * $Id: $
+ *
+ * Copyright (C) 2008 iptego GmbH
+ * Based on the concept of auth_b2b, Copyright (C) 2008 iptego GmbH
+ * Based on the concept of sw_prepaid_sip, Copyright (C) 2007 Sipwise GmbH
+ * Based on the concept of mycc, Copyright (C) 2002-2003 Fhg Fokus
+ *
+ * This file is part of sems, a free SIP media server.
+ *
+ * sems is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * For a license to use the sems software under conditions
+ * other than those described here, or to purchase support for this
+ * software, please contact iptel.org by e-mail at the following addresses:
+ *    info@iptel.org
+ *
+ * sems is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifndef _AUTH_B2B_H
+#define _AUTH_B2B_H
+
+#include "AmB2BSession.h"
+
+using std::string;
+
+class CallTimerFactory: public AmSessionFactory
+{
+ public:
+  AmDynInvokeFactory* user_timer_fact; 
+
+  static unsigned int DefaultCallTimer; 
+  static bool UseAppParam;
+
+  CallTimerFactory(const string& _app_name);
+  ~CallTimerFactory();
+
+  int onLoad();
+  AmSession* onInvite(const AmSipRequest& req);
+};
+
+class CallTimerDialog : public AmB2BCallerSession
+{
+  enum {
+    BB_Init = 0,
+    BB_Dialing,
+    BB_Connected,
+    BB_Teardown
+  } CallerState;
+
+  int m_state;
+  
+  AmDynInvoke* m_user_timer;
+
+  unsigned int call_time;
+
+ public:
+
+  CallTimerDialog(AmDynInvoke* user_timer, 
+		  unsigned int call_time);
+  ~CallTimerDialog();
+  
+  void process(AmEvent* ev);
+  void onBye(const AmSipRequest& req);
+  void onInvite(const AmSipRequest& req);
+  void onCancel();
+  
+
+ protected:
+  
+  bool onOtherReply(const AmSipReply& reply);
+  void onOtherBye(const AmSipRequest& req);
+};
+#endif                           
diff --git a/apps/call_timer/Makefile b/apps/call_timer/Makefile
new file mode 100644
index 00000000..c2380e70
--- /dev/null
+++ b/apps/call_timer/Makefile
@@ -0,0 +1,7 @@
+plug_in_name = call_timer
+
+module_ldflags =
+module_cflags  = -DMOD_NAME=\"$(plug_in_name)\"
+
+COREPATH ?= ../../core
+include $(COREPATH)/plug-in/Makefile.app_module
diff --git a/apps/call_timer/etc/call_timer.conf b/apps/call_timer/etc/call_timer.conf
new file mode 100644
index 00000000..ff4da06b
--- /dev/null
+++ b/apps/call_timer/etc/call_timer.conf
@@ -0,0 +1,13 @@
+
+#
+# use_app_param=[yes|no]
+#
+# sets whether App-Param header is used for call time value
+# (or default_call_time below)
+#
+use_app_param=yes
+
+#
+# call timer value used if not in P-App-Param. in seconds
+#
+default_call_time=1200
\ No newline at end of file
diff --git a/doc/Readme.call_timer b/doc/Readme.call_timer
new file mode 100644
index 00000000..12d0ba76
--- /dev/null
+++ b/doc/Readme.call_timer
@@ -0,0 +1,23 @@
+call_timer application
+----------------------
+
+call_timer is a simple back-to-back user agent application 
+that ends the call after a call timer expired. 
+
+If use_app_param is configured to "yes", then the call timer value 
+is taken from App-Param "t" or "Timer" value. If it is set to "no" 
+or that is not present, the configured default value is used.
+
+The default value is configured with default_call_time config option. 
+If that is not present, 1200 seconds are used.
+
+Examples (ser script): 
+ remove_hf("P-App-Param");
+ append_hf("P-App-Param: t=120\r\n");
+ t_relay_to_udp("10.0.0.3","5070");
+
+ remove_hf("P-App-Param");
+ append_hf("P-App-Param: Timer=120\r\n");
+ t_relay_to_udp("10.0.0.3","5070");
+
+