diff --git a/freedcs/api/models.py b/freedcs/api/models.py
index 6e22b08..650907f 100644
--- a/freedcs/api/models.py
+++ b/freedcs/api/models.py
@@ -3,8 +3,16 @@ from django.core.exceptions import ValidationError
 
 
 def device_validation(value):
-    published_devices = WhiteList.objects.filter(serial=value,
-                                                 is_published=True)
+    if value.startswith('ZZ'):  # simulated devices
+        published_devices = WhiteList.objects.filter(
+            serial='ZZ%',
+            is_published=True
+        )
+    else:
+        published_devices = WhiteList.objects.filter(
+            serial=value,
+            is_published=True
+        )
     if not published_devices:
         raise ValidationError("Device is not published")
 
diff --git a/freedcs/api/serializers.py b/freedcs/api/serializers.py
index cce3fbe..80d4434 100644
--- a/freedcs/api/serializers.py
+++ b/freedcs/api/serializers.py
@@ -1,14 +1,21 @@
 from rest_framework import serializers
-from api.models import Device, WhiteList
+from api.models import Device, device_validation
 
 
 class DeviceSerializer(serializers.ModelSerializer):
+    serial = serializers.CharField(
+        max_length=128,
+        validators=[device_validation],
+    )  # disable unique validation
+
     class Meta:
         model = Device
-        fields = ('serial', 'creation_time', 'updated_time',)
+        fields = '__all__'
+        read_only_fields = ('creation_time', 'updated_time')
 
-
-# class WhiteListSerializer(serializers.ModelSerializer):
-#     class Meta:
-#         model = Device
-#         fields = ('serial', 'creation_time', 'updated_time',)
+    def create(self, validated_data):
+        device, created = Device.objects.update_or_create(
+            serial=validated_data['serial'],
+            defaults={'serial': validated_data['serial']},
+        )
+        return device