diff --git a/tests/test_source_phone.py b/tests/test_source_phone.py
index 0bbc124..b855407 100644
--- a/tests/test_source_phone.py
+++ b/tests/test_source_phone.py
@@ -19,6 +19,7 @@ import json
 import pytest
 
 from django.core.urlresolvers import reverse
+from django.test import override_settings
 
 from welco.sources.phone import models
 
@@ -95,6 +96,43 @@ def test_call_start_stop(client):
         data=json.dumps(payload['data']), stop__isnull=False).count() == 2
 
 
+def test_one_call_per_callee(user, client):
+    assert models.PhoneCall.objects.count() == 0
+    payload = {'event': 'start', 'caller': '0033699999999', 'callee': '102'}
+    response = client.post(reverse('phone-call-event'), json.dumps(payload),
+                           content_type='application/json')
+    assert response.status_code == 200
+    assert models.PhoneCall.objects.filter(callee='102', stop__isnull=True).count() == 1  # active
+    assert models.PhoneCall.objects.filter(callee='102', stop__isnull=False).count() == 0 # inactive
+
+    # new caller, same callee: stops the last call, start a new one
+    payload['caller'] = '00337123456789'
+    response = client.post(reverse('phone-call-event'), json.dumps(payload),
+                           content_type='application/json')
+    assert response.status_code == 200
+    assert models.PhoneCall.objects.count() == 2
+    assert models.PhoneCall.objects.filter(
+        caller='00337123456789', callee='102', stop__isnull=True).count() == 1
+    assert models.PhoneCall.objects.filter(
+        caller='0033699999999', callee='102', stop__isnull=False).count() == 1
+
+    with override_settings(PHONE_ONE_CALL_PER_CALLEE=False):
+        # accept multiple call: start a new one, don't stop anything
+        payload['caller'] = '00221774261500'
+        response = client.post(reverse('phone-call-event'), json.dumps(payload),
+                               content_type='application/json')
+        assert response.status_code == 200
+        assert models.PhoneCall.objects.count() == 3
+        assert models.PhoneCall.objects.filter(callee='102', stop__isnull=True).count() == 2
+        assert models.PhoneCall.objects.filter(callee='102', stop__isnull=False).count() == 1
+        # same caller: stop his last call, add a new one
+        response = client.post(reverse('phone-call-event'), json.dumps(payload),
+                               content_type='application/json')
+        assert response.status_code == 200
+        assert models.PhoneCall.objects.count() == 4
+        assert models.PhoneCall.objects.filter(callee='102', stop__isnull=True).count() == 2
+        assert models.PhoneCall.objects.filter(callee='102', stop__isnull=False).count() == 2
+
 def test_current_calls(user, client):
     # create some calls
     for number in range(0, 10):
diff --git a/welco/settings.py b/welco/settings.py
index 033f32a..e0438cd 100644
--- a/welco/settings.py
+++ b/welco/settings.py
@@ -198,6 +198,9 @@ COUNTER_LINKS = [
     {'label': 'Wikipedia', 'url': 'https://fr.wikipedia.org'}
 ]
 
+# phone system
+PHONE_ONE_CALL_PER_CALLEE = True
+
 # enable/disable specific features
 # ex: FLAVOURS = ['alfortville']
 FLAVOURS = []
diff --git a/welco/sources/phone/views.py b/welco/sources/phone/views.py
index 955f8ef..0211bc4 100644
--- a/welco/sources/phone/views.py
+++ b/welco/sources/phone/views.py
@@ -18,6 +18,7 @@ import json
 import logging
 
 from django import template
+from django.conf import settings
 from django.contrib.contenttypes.models import ContentType
 from django.template import RequestContext
 from django.views.decorators.csrf import csrf_exempt
@@ -97,10 +98,16 @@ def call_event(request):
         return HttpResponseBadRequest(json.dumps({'err': 1, 'msg':
                                                   unicode(e)}),
                                       content_type='application/json')
-    # terminate all existing calls between these two endpoints
-    PhoneCall.objects.filter(caller=payload['caller'],
-                             callee=payload['callee'], stop__isnull=True) \
-        .update(stop=now())
+    # janitoring: stop active calls to the callee
+    if settings.PHONE_ONE_CALL_PER_CALLEE:
+        logger.info('stop all calls to %s', payload['callee'])
+        PhoneCall.objects.filter(callee=payload['callee'],
+                                 stop__isnull=True).update(stop=now())
+    else:
+        logger.info('stop call from %s to %s', payload['caller'], payload['callee'])
+        PhoneCall.objects.filter(caller=payload['caller'],
+                                 callee=payload['callee'],
+                                 stop__isnull=True).update(stop=now())
     if payload['event'] == 'start':
         # start a new call
         kwargs = {
@@ -111,8 +118,6 @@ def call_event(request):
             kwargs['data'] = json.dumps(payload['data'])
         PhoneCall.objects.create(**kwargs)
         logger.info('start call from %s to %s', payload['caller'], payload['callee'])
-    else:
-        logger.info('stop call from %s to %s', payload['caller'], payload['callee'])
     return HttpResponse(json.dumps({'err': 0}), content_type='application/json')