diff --git a/api/serializers.py b/api/serializers.py
index e7b23f32..af92e0d0 100644
--- a/api/serializers.py
+++ b/api/serializers.py
@@ -811,7 +811,8 @@ class SwitchPortSerializer(serializers.ModelSerializer):
         model = topologie.Switch
         fields = ('short_name', 'model', 'switchbay', 'ports', 'ipv4', 'ipv6',
                   'interfaces_subnet', 'interfaces6_subnet', 'automatic_provision', 'rest_enabled',
-                  'web_management_enabled', 'get_radius_key_value', 'get_management_cred_value')
+                  'web_management_enabled', 'get_radius_key_value', 'get_management_cred_value',
+                  'list_modules')
 
 # LOCAL EMAILS
 
diff --git a/topologie/models.py b/topologie/models.py
index b2c75f24..fd054c43 100644
--- a/topologie/models.py
+++ b/topologie/models.py
@@ -372,7 +372,7 @@ class Switch(AclMixin, Machine):
     def list_modules(self):
         """Return modules of that switch, list of dict (rank, reference)"""
         modules = []
-        if self.model.is_modular:
+        if getattr(self.model, 'is_modular', None):
             if self.model.is_itself_module:
                 modules.append((1, self.model.reference))
             for module_of_self in self.moduleonswitch_set.all():